Perception Channels: visual ; tactile ; acoustic ; chemical
Perisoreus canadensis is locally common over its wide range, but there is little precise population data. The Breeding Bird Surveys (BBS) from 1966 to 1993 show a -0.6% decline over that period, but with a statistically insignificant sample. The short-term BBS data trend from 1984 to 1993 show a 51.8% increase during that time (P
The Gray Jay is not listed as Endangered or Threatened in the United States or Canada. No special management measures have been implemented for the species.
(Madge 1994, Price 1995)
US Migratory Bird Act: protected
US Federal List: no special status
CITES: no special status
State of Michigan List: no special status
IUCN Red List of Threatened Species: least concern
While many corvids can cause extensive crop damage, the Gray Jay, because of its habitat requirements, does not overlap with farms. It can, however, be an annoyance (some would say a great delight) to campers, as it will linger in campsites and attempt to pilfer food.
Perisoreus canadensis is valuable as an indicator of the health of boreal and sub-alpine systems. Although these areas are less altered than most biomes, acid precipitation and global climate change could have a noticeable effect on this species. Because they are specially adapted to harsh winter environments, Gray Jays may be negatively impacted by warming trends. Thus, the species could serve as an early-warning system for cascading effects of anthropogenic climate change.
Gray Jays are omnivorous, commonly eating arthropods, berries, carrion, eggs, nestling birds, and fungi. Gray Jays use a variety of foraging techniques including flycatching, foliage gleaning, ground gleaning, and even aerial pursuit of rodents. Nestlings are fed partially digested food.
One of the most interesting traits of the Gray Jay is its food storage ability. This Jay has unusually large salivary glands that produce copious sticky saliva. They use this saliva to impregnate and encase food, creating a bolus that will adhere to trees. Away from ground scavengers and protected from the wind and snow, these caches allow efficient food hoarding. Gray Jays have been observed making over 1,000 caches in a single 17-hour day. This behavior may be the major adaptation enabling Perisoreus canadensis to occupy the hostile boreal regions during the winter. Fittingly, the genus Perisoreus means "hoarder."
(Dow 1965, Ehrlich 1988, Strickland 1993, Terres 1995)
Breeding range: The Gray Jay is found from tree line in northern Canada and Alaska south through boreal and subalpine forests to northern California on the west coast, Arizona and New Mexico in the Rocky Mountains, northern Wisconsin in the midwest, and New York in the east.
Winter range: The non-breeding range is essentially the same as the breeding range, as the Gray Jay does not migrate except for (in late fall and winter) occasional altitudinal movements in the Rockies and rare latitudinal movements elsewhere, probably due to food shortages.
Perisoreus canadensis has never been recorded outside of North America.
(Sibley 2000, Strickland 1993, Ehrlich 1988)
Biogeographic Regions: nearctic (Native )
Gray Jays are associated with coniferous and coniferous-deciduous forests of the boreal and sub-alpine vegetative regions. They are most commonly found in spruce and fir woods (with occasional aspens or birch). Despite its association with humans, this jay does not live in towns or developments. It is exclusively a bird of remote forests. In fact, Gray Jays disappear as soon as a camp becomes a permanent settlement.
(Strickland 1993, Madge 1994, Goodwin 1986)
Average lifespan
Status: wild: 185 months.
Often described as resembling an oversized chickadee, P. canadensis is a fluffy, pale-gray, long-tailed, short-billed, crestless jay. Gray Jays, while sexually monomorphic, do show strong regional variation, with three distinguishable populations: Pacific, Rocky Mountain, and Taiga. All adult variations have black eyes, bills, legs, and feet and white auriculars (ear patches) and throats. Pacific birds show extensive dark on the head and brownish-tinged backs. Rocky Mountain birds south of Canada have a whiter head. Taiga birds resemble Pacific birds, but are grayer above and have a grayer (rather than whitish) belly. Juveniles from all populations are sooty overall and gray-billed with white malar stripes.
Perisoreus canadensis is 11.5 inches (29 cm) long and has a wingspan of 18 inches (45 cm). Normal adult weight is 2.5 ounces (70 grams).
Gray Jays have a clear, pleasant whistle of wheeeooo or wheee-ah. Calls also include a low, husky chuf-chuf-weef and a very rough, dry kreh kreh kreh kreh alarm call. Like Blue Jays, P. canadensis sometimes sound a screeching jaaay. Gray Jays are known to mimic sounds.
(Sibley 2000, Peterson 1990)
Other Physical Features: endothermic ; bilateral symmetry
Average mass: 70.3 g.
Perisoreus canadensis breeds in coniferous forests and sometimes in mixed coniferous-deciduous woodlands. The male chooses a nest site usually in a conifer (spruce or fir), at a height of 5 to 12 feet (1.5 - 3.6 m), sometimes as high as 30 feet (9.1 m). The male initiates building the nest - a thick cup of twigs, bark strips, grass, moss, lichen, and spider webs. The inside is lined with fine grasses, moss, hair, feathers, and fur. The female joins the building over a period of up to 3 weeks or more.
The breeding season begins in March, while snow is still on the ground and temperatures are well below freezing, and ends by mid-May. Curiously, second broods are not attempted in ostensibly favorable later months. Three to four eggs (29 X 21 mm) are laid (range 2-5) and incubated by the female alone. The eggs are pale greenish or gray-green and heavily speckled, spotted, or blotched with olive and paler gray. After a 16 to 18 day incubation period, the nestlings hatch slightly downy and altricial. The young are fed by both parents and fledge at 22 to 24 days.
Cowbird parasitism has not been observed.
(Baicich 1997, Veghte 1964)
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average time to hatching: 17 days.
Average eggs per season: 3.
Conifers, particularly spruce (Picea spp.), are the preferred cover for the gray jay. The territory size for a pair of gray jays in Algonquin Provincial Park and La Verendrye Provincial Park was 0.25 square mile [97].
Stand age: Although gray jays prefer mature coniferous forests [56,73,87,97,106,113,120], they can be found occupying all forest age classes [121,124].
Mature forest: During winter months, gray jays preferred late-seral (325 to >500 years old) Douglas-fir (Pseudotsuga menziesii) stands in the southern Gifford Pinchot National Forest, Washington [56].
Gray jays surveyed in young (40-70 years old), mature (100-196 years), and old-growth (204-450 years) Douglas-fir/hardwood stands in northwestern California and southwestern Oregon reached peak abundance in the old-growth stands [87].
Gray jays were most abundant in mature stands and least abundant in young stands of a quaking aspen (Populus tremuloides) mixed-wood forest in Alberta. The 3 age classes studied were: young (20-30 years old); mature (50-65 years old); and old stands (120+ years old) [99].
Of 5 seral stages studied in a forest dominated by Douglas-fir, western hemlock (Tsuga heterophylla), and red alder (Alnus rubra) in the Oregon Coast Ranges, gray jays were significantly (P<0.05) positively associated with late-seral forest structure and were most abundant in large saw timber plots (>20% cover, >21 inch (>53.2 cm) mean DBH) [73].
All age classes: Habitat generalists including the gray jay were common in all 3 age classes (40-59 years, 60-79 years, and 80+ years) of mature balsam fir forest in Newfoundland [121].
In ponderosa pine (Pinus ponderosa) habitat in the Black Hills, South Dakota, gray jays utilized the sapling-pole, mature, and old-growth stages, but their habitat preference changed between the summer breeding season and winter [75,96]. During summer, optimal habitat included mature and old-growth ponderosa pine [75]. During winter, gray jays preferred mature and sapling-pole ponderosa pine stands [96].
As habitat generalists, gray jays may not be susceptible to changes in forest age distribution in jack pine (Pinus banksiana) forests near the White River in north-central Ontario. Jack pine stands were even-aged and ranged from 3 to 100 years old. Gray jays were most abundant on 18- to 20- year-old stands, but were not confined to that age class [124].
During the winter gray jay populations were greatest in the youngest stands (14 years old) compared to 30-year-old and 60-year-old stands in a mixed-age quaking aspen forest at Medicine Lake, Alberta [132].
Stand composition/structure: Most of the research on gray jays has compared various silvicultural strategies or analyzed succession after harvesting. Gray jays exhibit a range of responses to habitat fragmentation. They can be positively [51,62] or negatively affected [36,37] and, in most cases, show mixed or no response [10,25,44,46,84].
Positively affected by fragmentation: The mean number of bird species was measured in old-growth, fragmented old-growth and selectively harvested western redcedar (Thuja plicata)-western hemlock forests on the Priest Lake Ranger District of the Idaho Panhandle National Forest. Gray jay populations were greatest in the fragmented old-growth forest, characterized as an older-aged forest with 1- to 8-year-old clearcuts embedded [51]:
Mean number (s x ) of gray jays along 24 counting points in each area Old growth Fragmented old growth Selectively harvested P 0.06 (0.03) 0.14 (0.09) 0.03 (0.02) 0.04The mean abundance of gray jay was greater on clearcut stands than unfragmented stands in a forest dominated by Engelmann spruce (Picea engelmannii) and subalpine fir (Abies lasiocarpa) in the Medicine Bow National Forest, Wyoming, but the differences were not statistically significant [62].
Negatively affected by fragmentation: Birds such as the gray jay, which forage in the foliage of trees, may decline following logging due to the reduction of total biomass foliage rather than decreased foliage height diversity or loss of tree volume. A decline in insect prey may also occur following logging [36,37].
Mixed responses to habitat fragmentation: During the winter in Oregon, gray jay abundance did not differ between commercially thinned and unthinned Douglas-fir stands in the Tillamook State Forest and the central Coast Ranges. Four thinned and four unthinned stands that were 40 to 55 years old and 161 to 1,260 acres (65-510 ha) in size were chosen in each of 2 locations. During the summer gray jays were more abundant (P<0.01) in unthinned versus thinned stands in the Tillamook State Forest; however, they were more abundant (P=0.10) in thinned versus unthinned stands in the central Oregon Coast Ranges. The abundance of gray jays varied positively with red alder cover and negatively with pole layer height.
Bird populations were compared in 6 lodgepole pine (Pinus contorta) communities in the Uinta Mountains of Utah. The 6 communities were mature forest; stagnated forest composed of dense lodgepole pine stands; a 1940 clearcut that left no residual trees; a stagnated stand that was bulldozed and then broadcast burned; wet meadows along streams; and dry meadows with a dense mixture of grasses and forbs under widely scattered lodgepole pine. Gray jays were present in most of the communities and appeared to be uninfluenced by logging [10]:
Density of gray jays (individuals/100 acres (40 ha)) Mature forest Stagnated forest 1940 clearcut forest Bulldozed & burned forest Wet meadow Dry meadow 6 <1 <1 4 ---- 7Breeding bird responses to 3 silvicultural alternatives were examined in a Douglas-fir forest on the McDonald-Dunn Forest, Oregon. The 3 treatments were: (1) small-patch group selection, in which ⅓rd of the wood volume was removed, representing low-severity disturbance; (2) 2-story treatment, in which ¾ths of the wood volume was removed, representing a moderate to high-severity disturbance; (3) modified clearcut treatment, in which 1.2 green trees/ha were retained, representing a high-severity disturbance; and (4) unharvested control for each treatment. One replicate was harvested each year for 3 years. The mean abundance of gray jays was highest in small-patch group selection cuts for each of the 3 years [25]:
Mean abundance of gray jays (no. of observations/5 ha (s x)) Year 1 Year 2 Year 3 Control 0.3 (0.3) 1.3 (1.3) 1.0 (0.6) Small-patch 1.8 (0.5) 1.6 (0.6) 1.1 (0.4) 2-story 1.7 (1.2) 0.5 (0.3) 0.2 (0.2) Modified clearcut 1.5 (0.6) 0.0 (0.0) 0.2 (0.2)Harrison and others [46] studied the effects of partial cutting on songbirds in mixed-wood forests near Peace River in northwestern Alberta. Dominant trees included quaking aspen, balsam poplar, and lodgepole pine. The mean abundance change for gray jay was not statistically significant.
Six seral stages within a sub-boreal spruce forest dominated by quaking aspen in valley bottoms and lowlands were surveyed to examine diversity of bird communities near Smithers, British Columbia. The seral stages were clearcut; shrub/herb; pole/sapling (<15 years); young quaking aspen (15- 49 years); mature quaking aspen (50+ years); and mature quaking aspen mixed with Engelmann spruce and lodgepole pine. Gray jays were present in the mixed quaking aspen stage and seen foraging in clearcuts, but were probably not nesting in the clearcut due to lack of suitable habitat [84].
The gray jay is a native resident from northern Alaska east to Newfoundland and Labrador and south to northern California, Idaho, Utah, east-central Arizona, north-central New Mexico, central Colorado, and southwestern South Dakota. It is also a native resident in northern Minnesota, northern Wisconsin, northern Michigan, northern New York, and northern New England. The gray jay may wander north of the breeding range. In winter it travels irregularly to northwestern Nebraska, central Minnesota, southeastern Wisconsin, central Michigan, southern Pennsylvania, central New York, Connecticut, and Massachusetts [3,4,113].
Perisoreus canadensis albescens is a resident from northeastern British Columbia and northwestern Alberta southeastward, east of the Rocky Mountains to South Dakota (Black Hills). It< is casual in northwestern Nebraska [3].
Perisoreus c. arcus is a resident in the Rainbow Mountains area, and headwaters of the Dean and Bella Coola Rivers of the central Coast Ranges, British Columbia [3].
Perisoreus c. barbouri is a resident on Anticosti Island, Quebec [3].
Perisoreus c. bicolor is a resident in southeastern British Columbia, southwestern Alberta, eastern Washington, northeastern Oregon, northern and central Idaho, and western Montana [3].
Perisoreus c. canadensis breeds from northern British Columbia east to Prince Edward Island, and south to northern Minnesota, northern Wisconsin, northern Michigan, northeastern New York, northern Vermont, northern New Hampshire, and Maine. It winters at lower altitudes within the breeding range and south to southern Ontario and Massachusetts, casually to central Minnesota, southeastern Wisconsin, northwestern Pennsylvania, and central New York. Perisoreus c. canadensis is accidental in northeastern Pennsylvania (Philadelphia) [3].
Perisoreus c. capitalis is a resident in the southern Rocky Mountains from eastern Idaho, central south-central Montana, and western and southern Wyoming south through eastern Utah, and western and central Colorado, to central eastern Arizona and north-central New Mexico [3].
Perisoreus c. griseus is a resident from southwestern British Columbia and Vancouver Island south through central Washington and central Oregon to the mountains of north-central and northeastern California [3].
Perisoreus c. nigracapillus is a resident in northern Quebec (Fort Chimo, Whale River, and George River), throughout Labrador, and in southeastern Quebec (Mingan and Blanc Sablon) [3].
Perisoreus c. obscurus is a resident in the coastal belt from Washington (Crescent Lake, Seattle, and Columbia River) through western Oregon to northwestern California (Humboldt County) [3].
Perisoreus c. pacificus is a resident in north-central Alaska (Kobuk River, Endicott Mountains, and Fort Yukon), northern Yukon (Arctic Circle at the International Boundary), and northwestern Mackenzie (Mackenzie Delta and lower Horton River) south in Alaska to latitude 60° N [3].
Perisoreus c. sanfordi is a resident in Newfoundland and Nova Scotia [3].
Gray jays are omnivorous [76,97,98,113]. Foods eaten include arthropods [113], small mammals [68], nestling birds [21,22,116,123] (see Predation), carrion [97,113], fungi [113], fruits such as chokecherry (Prunus virginiana) [97], and seeds [97]. Two gray jays were seen eating slime mold (Fuligo septica) near Kennedy Hot Springs in the Glacier Peak Wilderness, Washington. This was the 1st report of any bird consuming slime mold in the field [117].
Occasionally, gray jays eat live prey. Lescher and Lescher [68] witnessed a gray jay kill an unidentified, live small rodent in Wisconsin. Barnard [12] was the 1st to witness an in-flight gray jay capture of a magnolia warbler (Dendroica magnolia) for consumption.
Gray jays have been seen landing on moose (Alces alces) to remove and eat engorged winter deer ticks (Dermacentor albipictus) during April and May in Algonquin Provincial Park. Researchers also found a gray jay nest containing a brooding female, 3 hatchlings, and 3 warm, engorged winter deer ticks. Because the winter deer ticks were too large for the hatchlings to eat, it was hypothesized that the ticks may have served as "hot water bottles", keeping hatchlings warm when parents were away from the nest [1].
Gray jays are suspected but not proven to prey on nests of the threatened marbled murrelet (Brachyramphus marmoratus) in coastal areas of the Pacific Northwest [88].
Foraging behavior: Gray jays do not hammer food with their bill as do other jays, but wrench, twist, and tug food apart. Gray jays commonly carry large food items to nearby trees to eat or process for storage, possibly as defense against large scavengers [113]. They are "scatterhoarders", caching food items among scattered sites for later consumption [69,71,128].
Any food intended for storage is manipulated in the mouth and formed into a bolus (rounded mass) that is coated with sticky saliva, adhering to anything it touches. The bolus is stored in bark crevices, under tufts of lichen, or among conifer needles [97].
Risk and energy expenditure are factors in food selection for gray jays. Gray jays select food on the basis of profitability to maximize caloric intake. Increased handling, searching, or recognition times for a preferred food item lowers its profitability [71].
The gray jay takes advantage of man-made sources of food, hence the names "camp robber" and "whiskey Jack". According to Maccarone and Montevecchi [71], human observers do not inhibit gray jay's feeding behavior; however, Rutter [97] claims that "once having identified man with food it does not forget". He found that after a nesting female was accustomed to being fed by humans she could be enticed to leave the nest during incubation and brooding [97].
Predation: Gray jays commonly prey on nestling birds [22,29,88,123]. Nests are located visually by moving from perch to perch and scanning surroundings [113]. Gray jay predation on nestling birds is temporally homogenous throughout the passerine breeding season [105]. Avian nest predation by gray jays is not necessarily higher in fragmented versus unfragmented forest [21,29,116,123].
Boulet and others [21] examined bird nest predation in a commercially fragmented boreal black spruce forest intermixed with jack pine, balsam fir, quaking aspen, and paper birch near Lake Saint-Jean, Quebec. Gray jays directed their attacks on artificial arboreal nests more often than artificial ground nests. Depredation of nests was positively related to the presence of the lake and jack pine. Gray jays may have preferred preying on avian nests in jack pine versus black spruce habitat because jack pine forests were more open, and trees did not conceal nests as well. Gray jays may have favored foraging along lakeshores and moist patches due to the high density of insects. No relationship was found between the fragmented forest and predation [21].
The potential for egg predation by gray jays was greater in riparian forest strips than in clearcuts in a second-growth boreal balsam fir forest in Montmorency Forest, Quebec [29].
Stuart-Smith and Hayes [116] examined the influence of residual tree density on predation of artificial and natural songbird nests. The study took place in the White River and Lussier River Watershed, southeastern British Columbia, in a forest dominated by Douglas-fir, white spruce, and western larch. Twenty-four plots of similar age were chosen (16 logged, 8 burned by wildfire); they varied in residual tree density between 0 and 180 trees/ha. Residual trees apparently did not increase predation on nesting songbirds by the gray jay. However, a moderate increase in nest predation occurred in logged plots adjacent to or surrounded by mature conifer forest, which is the preferred habitat for gray jays [56,87,97,106,113,120]. Retaining residual trees would outweigh the possible increased risk of nest predation, except in areas where nesting birds are at very low numbers and potential risk by gray jays is high [116].
When predation rates on bird nests by the gray jay were compared in clearcut, green-tree retention stands, and mature western hemlock stands in the west-central Oregon Cascade Ranges, predation rates were highest in green-tree retention stands. This may have been due to increased availability of perch sites for avian predators such as the gray jay [123].
Caching: Gray jays cache thousands of food items every day during the summer for use the following winter [112,126,127,129]. Caching behavior is thought to have evolved for several reasons. It allows for permanent residence in boreal and subalpine forests [113], ensures a food source in areas with high elevations and cyclic availability of food resources, and favors the retention of young and a kin-selected social organization [92]. In southern portions of the gray jay's range, food is not cached during summer because of the chance of spoilage and the reduced need for winter stores [113]. Cached items can be anything from carrion to bread crumbs and are formed into a bolus before being cached [97]. Cached food is sometimes used to feed nestlings and fledglings [97].
Caching is inhibited by the presence of Steller's jays [23] and gray jays from adjacent territories [126,127], which follow resident gray jays to steal cached food [23]. Gray jays carry large food items to distant cache sites for storage more often than small food items. To prevent theft, they also tend to carry valuable food items further from the source when caching in the company of 1 or more gray jays [127]. Scatterhoarding discourages pilferage by competitors. Cache thievery increases with increased cache density [126].
When exploiting distant food sources found in clearings, gray jays temporarily concentrated their caches in an arboreal site along the edge of a black spruce forest in interior Alaska. This allowed a high rate of caching in the short term and reduced the jay's risk of predation. A subsequent recaching stage occurred, and food items were transferred to widely scattered sites to reduce theft [128].
Modifications in the food supply and habitat of gray jays may occur following fire, as well as changes in the abundance of competitors and predators [95]. According to Finch and others [33], the effects of fire on birds and their habitat vary with: 1) the severity and extent of the fire; 2) temporal scales; 3) life history characteristics of the bird species; and 4) whether or not salvage logging occurs following fire. Severe fires alter the forest structure more than low-severity fires, and a stand-replacing fire may result in the successional replacement of a bird species with a different bird species. Large, severe fires may greatly alter bird habitat in the short term but may be necessary for long-term maintenance of some forest types [58]. Fire may be beneficial to cavity-nesting, timber-drilling, grain-collecting, and fly-catching birds due to increased nesting habitat and food supplies [18,19,24,45,50,58,111,119]. Salvage logging may reduce the benefits of fire to birds that utilize snags for cavity nesting and foraging [58].
A meta-analysis of studies of bird responses to fire showed that gray jays and other bird species that share the same nest type, nest layer, and foraging guild do not show a distinct positive or negative response to fire. The analysis is shown below; the table does not distinguish between fire types (wildland, prescribed, stand-replacing, understory, various severities), vegetation types, or time since fire [98]:
Response to fire (% of studies) n positive negative none mixed Nest type: Open-cup nest 544 29 23 39 9 Nest layer: Canopy nest 423 31 18 42 9 Foraging guild: Omnivore 296 32 21 37 9Gray jays are usually present in postfire habitats after fires of varying severities but experience lower abundance in burned than unburned areas. Results of studies examining gray jay responses to wildfire, prescribed burning, logging versus burning, and salvage logging follow.
Wildfire: Changes in bird abundance and species composition following mixed-severity wildfires were studied in low-elevation ponderosa pine/Douglas-fir habitat and mid-elevation mixed-conifer and lodgepole pine habitats in the Bitterroot National Forest in west-central Montana. In July and August 2000, dry lightning storms ignited fires of 99 to 135,900 acres (40-55,000 ha) in size; the fires ranged from low-severity to severe. Transects had been established in 1994 and 1995 before the wildfires occurred, and 1 year following the fires, burned and unburned transects of differing fire severities were compared. The mean relative abundance (number of gray jays detected within 100 m/point à 100 ± standard error) for gray jays was lowest following fire [109,110]:
Mean relative abundance ± s x
Before fire
After fire
Unburned points (n=120) 9.8 ± 2.2 8.1 ± 2.1 Burned points (n=122) 12.4 ± 2.7 4.2 ± 1.5Gray jays were ubiquitous in various successional portions of lodgepole pine and Engelmann spruce-subalpine fir forests following wildfires in Grand Teton and Yellowstone National Parks, Wyoming; however, they were most abundant in severely burned areas 43 and 44 years following fire, which is typically when the canopy closes following severe wildfire. Ten areas were sampled in both Parks ranging from 1 to 304 years after fire and 40 to several hundred acres in size. In Grand Teton National Park, unburned, moderately burned, and severely burned areas were examined. In moderately burned areas, 40% or more of the tree understory was alive 1 year following the fire, and part of the grass-forb-shrub understory was unburned. In severely burned areas, all aboveground vegetation was killed by a severe crown fire. In Yellowstone National Park, all sampling areas were severely burned in 1667 and 1956 [119].
Gray jay densities were highest in unburned versus burned lodgepole pine and Engelmann spruce-subalpine fir forests in Yellowstone National Park, Wyoming. In 1974, the Trail Creek Wildfire burned 581 acres (235 ha) of 250-year-old lodgepole pine forest with an understory of Engelmann spruce and subalpine fir. In 1976, the Divide Wildfire burned 1,601 acres (648 ha) of 350+ year-old Engelmann spruce-subalpine fir forest. Fire severities were not documented. Avian communities were surveyed in 1978 and 1979 [83].
Gray jays preferred the ecotone and unburned areas of subalpine lodgepole pine forest 8 years following a high-severity wildfire on the Roosevelt National Forest, Colorado. The fire burned approximately 470 acres (190 ha), killing or top-killing virtually all aboveground vegetation. The total number of gray jays recorded on 6-point counts on three 49 acre (20 ha) plots is shown below [94]:
Total number of gray jays (and no. of territories)/ plot
Burned Ecotone Unburned 0 10 (2) 5 (1)A literature review reported that gray jays were more abundant on unburned sites than on 23 severely burned conifer forests in the western United States [63].
Canopy cover did not predict distribution of canopy foragers such as the gray jay between burned and unburned lodgepole pine forests in Grand Teton National Park. Two-year postfire and six-year postfire sites were compared with unburned sites. Details about the size and severity of the fires were not given. Gray jays utilized the 2-year burns, 6-year burns, and unburned sites most during the postbreeding season. The mean frequency of observations during the breeding and postbreeding season of the gray jay is shown below [108]:
Mean frequency of observations à 100 (frequency of observations)
Treatment
Postfire year 2
Postfire year 6 unburned Breeding season 4 (3) 5 (3) 2 (1) Postbreeding season 36 (17) 13 (5) 28 (8)Prescribed burning: Bock and Bock [20] studied the effects of prescribed fire on birds in ponderosa pine forests in the southern Black Hills, South Dakota. One area was burned in October 1979, covering 156 acres (63 ha). Another study area was burned in April and May 1980, burning 806 acres (326 ha). Both burns were low-severity in local isolated spots. Point counts were conducted in June 1980 and June 1981 on burned and unburned plots. Gray jay abundance was greatest on unburned plots for both years [20]:
Mean no. of breeding birds Year Burned Unburned 1980 0 0.7 1981 0.1 0.7Logging versus wildfire: Clearcutting and stand-replacing fire both lead to early-successional forest; however, they do not provide the same habitat conditions [53]. Clearcuts and wildfires are distinct from each other for several reasons: 1) logging causes greater site disturbance due to road construction and logging equipment; 2) logging removes stems from a site; 3) wildfire leaves live residual stands, burned trees, and downed woody debris; 4) wildfire size, frequency, and distribution are different from cutblocks; and 5) wildfire is not predictable and does not target the most valuable trees [58]. Nevertheless, research comparing gray jays on logged and burned sites does not show any clear pattern of preferences.
Bird communities were compared between burned and harvested sites in a quaking aspen-dominated boreal mixed-wood forest in north-central Alberta. Three replicate stands were chosen from each class (1,14, and 28 postdisturbance years) and treatment (wildfire vs. harvest). More than 95% of the canopy trees were dead on burned sites. An average of 6% of preharvest trees remained on the harvested sites. Gray jay density was greater within 14-year-old postfire stands than in postharvest stands. Gray jays may have been responding to differences in the herb and shrub strata between postfire and postharvest stands [53]:
Density of gray jays (mean number of individuals (± s x)/25acres) Postdisturbance year 1 14 28 Postfire 0.7 ± 0.7 4.3 ± 2.0 1.3 ± 0.3 Postharvest 1.7 ± 0.9 0.0 ± 0.0 0.0 ± 0.0Avian response to forest management practices was examined in mature ponderosa pine forests mixed with Douglas-fir or grand fir (Abies grandis) in Montana. Three site categories were chosen: 1) control sites containing either ladder fuels or encroachment by small- or medium- diameter trees; 2) treated sites that had been logged, underburned, or a combination of the 2 to reduce fuels and create open structural conditions; and 3) sites with a natural underburn in 2000. Gray jays were present in all 3 sites but most abundant in the control [133].
In northwestern Lac Saint Jean, Quebec, gray jays showed no significant (P>0.05) difference in abundance in postfire and postlogging stages in stands formerly dominated by black spruce [59].
Avian abundance was compared in wildfire and clearcut areas in a former black spruce forest near Goose Bay, Newfoundland after 5,14, and 27 years of succession. Details about the size and severity of the burn were not documented. Gray jay was not a common species in the study area but may have slightly preferred clearcut plots over burned plots [107].
Schulte and Niemi [100] surveyed bird communities in early-successional forests following logging and fire near Tower, Minnesota. Logged sites had been clearcut and contained residual trees and residual patches of trees. Wildfire sites were dominated by quaking aspen, and 5,189 acres (2,100 ha) of forest had burned. Logged sites were chosen to match the time of disturbance, predisturbance type, and soils of the burned sites. According to the vegetation analysis, habitat heterogeneity was greater in burned areas. The gray jay was 1 of 5 bird species highly associated with snags in this study; snags were probably utilized for foraging. Gray jay abundance did not differ significantly between logged and burned sites [100]:
Gray jay abundance (territorial males/ha)Mean
s x P value Logged 0.02 0.02 0.12 Burned 0.10 0.06Salvage logging: Resident species such as the gray jay were less likely to be detected in salvaged areas of a burned mixed-wood forest (dominant trees were white spruce and quaking aspen), a jack pine forest, and a quaking aspen forest near Meadow Lake, Saskatchewan than in logged areas. In 1995, a wildfire burned 98,840 acres (40,000 ha), killing a majority of the trees in the burned areas. Salvage logging took place in 1997. In 1998, surveys were conducted in unburned, burned, and salvaged forests. The indicator value of gray jay for each treatment in the 3 habitat types is shown below [76]:
Habitat type Indicator value (% ) Unburned Burned Salvaged P Mixed-wood 36 41 24 0.999 Jack pine 34 22 1 0.106 Quaking aspen 0 17 not salvaged 0.468The following table provides fire return intervals for plant communities and ecosystems where the gray jay is important. Find fire regime information for the plant communities in which this species may occur by entering the species name in the FEIS home page under "Find FIRE REGIMES".
Community or Ecosystem Dominant Species Fire Return Interval Range (years) silver fir-Douglas-fir Abies amabilis-Pseudotsuga menziesii var. menziesii >200 grand fir Abies grandis 35-200 [6] tamarack Larix laricina 35-200 [81] western larch Larix occidentalis 25-350 [7,14,30] Great Lakes spruce-fir Picea-Abies spp. 35 to >200 northeastern spruce-fir Picea-Abies spp. 35-200 [31] Engelmann spruce-subalpine fir Picea engelmannii-Abies lasiocarpa 35 to >200 [6] black spruce Picea mariana 35-200 conifer bog* Picea mariana-Larix laricina 35-200 [31] pinyon-juniper Pinus-Juniperus spp. <35 [81] whitebark pine* Pinus albicaulis 50-200 [2,5] jack pine Pinus banksiana <35 to 200 [28,31] Rocky Mountain lodgepole pine* Pinus contorta var. latifolia 25-340 [13,14,118] Colorado pinyon Pinus edulis 10-400+ [35,40,61,81] Sierra lodgepole pine* Pinus contorta var. murrayana 35-200 Pacific ponderosa pine* Pinus ponderosa var. ponderosa 1-47 [6] interior ponderosa pine* Pinus ponderosa var. scopulorum 2-30 [6,11,66] red pine (Great Lakes region) Pinus resinosa 3-18 (x=3-10) [27,38] red-white pine* (Great Lakes region) Pinus resinosa-P. strobus 3-200 [28,48,70] eastern white pine Pinus strobus 35-200 eastern white pine-eastern hemlock Pinus strobus-Tsuga canadensis 35-200 [125] aspen-birch Populus tremuloides-Betula papyrifera 35-200 [31,125] quaking aspen (west of the Great Plains) Populus tremuloides 7-120 [6,41,74] Rocky Mountain Douglas-fir* Pseudotsuga menziesii var. glauca 25-100 [6,8,9] coastal Douglas-fir* Pseudotsuga menziesii var. menziesii 40-240 [6,77,90] redwood Sequoia sempervirens 5-200 [6,34,115] western redcedar-western hemlock Thuja plicata-Tsuga heterophylla >200 western hemlock-Sitka spruce Tsuga heterophylla-Picea sitchensis >200 [6] *fire return interval varies widely; trends in variation are noted in the species reviewGray jay populations are decreasing slightly. Breeding Bird Surveys conducted from 1966 to 1992 revealed that gray jay populations declined at a rate of 1.28%/year [82]. Gray jay abundance decreased in ponderosa pine forests in New Mexico from 1911 to 1961 [101].
The Nicolet National Forest Bird Survey in northeastern Wisconsin showed gray jay populations decreased from 1989 to 2002; however, the Breeding Bird Survey conducted in the same forest found gray jay populations increased during this time. This may be because Breeding Bird Survey routes were established randomly along roadsides [91], whereas the Nicolet National Forest Bird Survey routes were established within gray jay habitat [54].
Members of a guild are more likely to respond similarly when they are grouped according to their association with habitat zones instead of by the "guild approach", which groups bird species into guilds based on their foraging and nesting behavior. According to Skinner [108], the "guild approach" may be problematic for 2 reasons: a lack of consistency in how investigators assign bird species to guilds and a false assumption that the response of 1 species in a guild is representative of all species in that guild [108].
Silviculture: Because gray jays prefer mature forests [56,75,87,97,102,106,113,120], management activities such as harvesting mature and old-growth ponderosa pine stands [75], clearcutting, conversion of hardwood or mixed stands to pure conifer stands, and a maximum rotation period of 100 years may reduce the quantity or quality of preferred habitat for the gray jay [106]. Nevertheless, maintaining as much landscape diversity as possible is beneficial to the gray jay [102]. For more information on silvicultural treatments and the gray jay, (see Stand composition/structure).
The amount and orientation of residual live and dead trees is an important component of stand structure following disturbance [53]. Wakkinen and Reese [130] and Hobson and Schieck [53] suggest managing for both dead and partially dead snags of different sizes in a variety of stand types to provide nesting, feeding, and perching sites for birds.
Dwarf mistletoe: Gray jays are one of the most common vectors in the long-distance dispersal of dwarf mistletoe (Arceuthobium spp.) seeds [16,47,79]. Seeds are inadvertently picked up on gray jay feathers when birds forage or nest in infected trees [55,79,86]. Bennetts and others [16] suggest control of dwarf mistletoe "may not be justified, practical, or even desirable" in areas where management goals are not focused on timber production. Pineland dwarf mistletoe (A. vaginatum) in central Colorado may have positive effects on avian habitat, creating a mosaic of habitat patches for nesting and cover [16].
Some timber management practices may reduce the quantity or quality of preferred habitat for the gray jay. A 150- year-old, even-aged western hemlock forest on the Siuslaw National Forest, Oregon, was inventoried for wildlife management needs. The gray jay, which may require western hemlock forests older than 100 years, may be adversely affected by timber management activities that include clearcutting, conversion of hardwood or mixed stands to pure conifer stands, and rotation periods of less than 100 years [106].
Other: The impact of repeated human intrusions on gray jays was studied in a subalpine forest in the Snowy Mountains of Wyoming. The average number of gray jays was higher on intruded sites than on control sites, as was the probability of intrusion reoccurring. The potential for gray jay predation may be higher in human-intruded areas, but more studies are needed [42].
The gray jay has a high potential for damage from exposure to aerial insecticide treatments due to open-cup nests [89].Gray jays warn each other of predators by whistling alarm notes, screaming, chattering, or imitating, and/or mobbing predators [113].
Gray jays are consumed by several bird species including great gray owls (Strix nebulosa) [78], northern hawk-owls (Surnia ulula) [93], and Mexican spotted owls (Strix occidentalis lucida) [122,131].
Gray jay remains were found in the nest sites of fisher (Martes pennanti) [85] and American marten (Martes americana) [52]. Red squirrel (Tamiasciurus hudsonicus) eat gray jay eggs [97].
Gray jays are habitat generalists [62,73,75,96,99,102,120,121,124,132] but prefer mature coniferous habitats [56,87,97,106,113,120] and mixed conifer-deciduous forests with spruce (Picea spp.) typically present [113].
Pure hardwood stands are used for foraging but are not part of the defended territory [97].
Theberge [120] examined the density of gray jays in various vegetation communities in Kluane National Park, Yukon. Gray jays were most abundant in the mature white spruce community but were present in 7 distinctly different vegetation communities, indicating a lack of habitat specialization [120]:
Vegetation community Upland willow (Salix spp.) shrub Lowland willow shrub White spruce-balsam poplar (Populus balsamifera ssp. balsamifera) Mature white spruce Riparian balsam poplar Balsam poplar parkland Subalpine Density of males per 40 ha 10.0 6.7 6.0 16.8 10.0 12.5 1.7
Mating: Gray jays typically breed at 2 years of age. Pairs are monogamous and remain together for their lifetime, but a male or female will find another mate following the disappearance or death of their partner [113]. Gray jay pairs breed during March and April, depending on latitude [97,112,113], in permanent, all-purpose territories [53,76,97,112,113]. Second broods are not attempted, perhaps allowing greater time for food storage (see Caching) [97,113].
Gray jays cooperatively breed [112,114,129]. Strickland [112] studied cooperative breeding of gray jays in Algonquin Provincial Park, Ontario, and La Verendrye Provincial Park, Quebec. In early June, when broods were 55 to 65 days old, the young fought amongst themselves until dominant juveniles forced their siblings to leave the natal area. Dominant juveniles, known as "stayers", remained with their parents, and "leavers" left the natal territory to join an unrelated pair who failed to breed. Two-thirds of "stayers" were male [112].
During the nest-building phase of the subsequent breeding season, approximately 65% of gray jay trios included "stayers" from the previous spring and their parents, and approximately 30% of trios included an unrelated "leaver". Occasionally, 2 nonbreeders accompany a pair of adults. "Stayers" may eventually inherit the natal territory and breed, and "leavers" may eventually fill a vacancy nearby or form a new breeding pair on previously unoccupied ground [112]. The role of "stayers" is to retrieve caches and bring food to younger siblings [114,129]; however, this is only allowed by the parents during the postfledgling period [112,114,129]. Until then, parents are hostile toward the "stayer". This may reduce the frequency of predator-attracting visits to the nest when young are most vulnerable. The benefits of allofeeding may include "lightening the load" for the breeding pair, which may possibly increase longevity, reducing the probability of starvation of nestlings, and detecting and mobbing predators near the nest [114].
Nesting: Nesting typically occurs in March and April [97,113]. Male gray jays choose a nest site in a mature coniferous tree [53,76] and take the lead in construction [113]. Gray jay nests were found in black spruce (Picea mariana), white spruce (Picea glauca), and balsam fir (Abies balsamea) trees in Ontario and Quebec, with black spruce predominating [97,113]. Cup-shaped nests [53,64,76,98] were constructed with brittle dead twigs pulled off of trees, as well as bark strips and lichens. Cocoons of the forest tent caterpillar (Malacosoma dysstria) filled the interstitial spaces of the nest [113]. Nests are usually built on the southwestern side of a tree for solar warming and are usually <1 nest diameter from the trunk [97]. Nest height is typically 8 to 30 feet (2.4-9.1 m) above the ground [72,97]. The average height of 264 nests surveyed in Algonquin Provincial Park was 16 feet ± 9.2 (4.9 m ± 2.8) above ground [97].
Clutch size is 2 to 5 eggs. The mean clutch sizes of gray jays in Algonquin Provincial Park and La Verendrye Provincial Park were 3.03 and 3.18 eggs, respectively. Incubation is performed only by the female [97,113] and lasts an average of 18.5 days [113].
Fledging: Gray jay young are altricial.
Nestling growth is most rapid from the 4th through the 10th day following hatching. Young are fed food carried in the throats of both parents [97,113]. They are fed by the accompanying nonbreeding 3rd bird ("stayer") only during the postfledgling period (see Mating) [114,129]. Food is a dark brown, viscous paste containing primarily arthropods [97,113]. Young gray jays leave the nest between 22 and 24 days after hatching [113]. Juveniles reach full adult measurements within 5 months [43].
Natal dispersal distance for the gray jay is a median of 0.0 mile (0.0 km) for males, 1.7 miles (2.8 km) for females, and a maximum distance of 7.0 miles (11.3 km) for males and females [112].
Survival: In studies conducted in Ontario and Quebec, the mortality rate for nonbreeding dominant juveniles ("stayers") was 52%, and mortality was 85% for nonbreeding "leavers" between fledging in June to approximately mid-October. From fall to the following breeding season in March, further nonbreeder mortality was 50%. Territory-holding adult gray jays experienced low mortality rates (15.1% and 18.2% for males and females, respectively) [112]. The oldest known female gray jay was 16 years old, and one male was at least 14 years old [113]. Food-storing birds such as the gray jay may live longer than other species due to the increased probability of food availability [92].
The data currently available suggest that gray jays are present in burned forests but are usually more abundant in unburned habitats [20,63,83,94,109,110,133]. This may be due to their preference for mature trees for foraging and nesting [53,56,76,87,97,106,113,120]. Because gray jays are habitat generalists [62,73,75,96,99,102,120,121,124,132] and omnivores [76,97,98,113], they may exhibit greater flexibility in response to habitat disturbances such as fire and logging than other bird species. Most studies examining gray jay response to fire have been conducted several years following wildfire. More research needs to be conducted on the immediate effects of low- and high-severity wildfire on gray jay, as well as the best time of year to conduct prescribed burning for gray jay management.
The amount and orientation of residual live and dead trees is an important component of stand structure following disturbance [53]. Gray jays utilize snags for perch sites [53,113,116,123,130], so they may be negatively affected by salvage logging. Wakkinen and Reese [130] and Hobson and Schieck [53] suggest managing for both dead and partially dead snags of different sizes in a variety of stand types to provide nesting, feeding, and perching sites for birds such as the gray jay.
Smucker and others [110] suggest that managers prescribe and allow for a range of fire severities to meet the needs of all bird species.
Les especies d'aves con nome común en llingua asturiana márquense como NOA. En casu contrariu, conséñase'l nome científicu o de la SEO.
El Perisoreus canadensis ye un córvidu común de los montes fríos norteamericanos. Ye un miembru de la llinia familiar jay (Corvidae) que puede ser atopada nos montes boreales d'América del Norte al norte de la llinia de vexetación arbórea y en montes subalpinos de los Montes Predresos al sur de Nuevu Méxicu y Arizona. Ye unu de los trés miembros del xéneru Perisoreus, siendo los otros el Perisoreus infaustus, que s'alcuentra dende Noruega hasta l'este de Rusia y el Perisoreus internigrans, llendada a los montes del este del Tíbet y el noroeste de Sichuan. Les trés especies almacenen alimentos y viven mientres tol añu nos territorios permanente nos montes de coníferes.
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Esta páxina forma parte del wikiproyeutu Aves, un esfuerciu collaborativu col fin d'ameyorar y organizar tolos conteníos rellacionaos con esti tema. Visita la páxina d'alderique del proyeutu pa collaborar y facer entrugues o suxerencies. Les especies d'aves con nome común en llingua asturiana márquense como NOA. En casu contrariu, conséñase'l nome científicu o de la SEO. El Perisoreus canadensis ye un córvidu común de los montes fríos norteamericanos. Ye un miembru de la llinia familiar jay (Corvidae) que puede ser atopada nos montes boreales d'América del Norte al norte de la llinia de vexetación arbórea y en montes subalpinos de los Montes Predresos al sur de Nuevu Méxicu y Arizona. Ye unu de los trés miembros del xéneru Perisoreus, siendo los otros el Perisoreus infaustus, que s'alcuentra dende Noruega hasta l'este de Rusia y el Perisoreus internigrans, llendada a los montes del este del Tíbet y el noroeste de Sichuan. Les trés especies almacenen alimentos y viven mientres tol añu nos territorios permanente nos montes de coníferes.
El gaig canadenc és un ocell de la família dels còrvids (Corvidae) que habita boscos de coníferes de l'oest i centre d'Alaska, la major part de Canadà des de Yukon, cap a l'est, fins al nord de Labrador i Terranova, i als Estats Units per les dos vessants de les Muntanyes Rocalloses.
En diverses llengües rep el nom de "gaig canadenc" (Francès: Mésangeai du Canada. Espanyol: Arrendajo canadiense).
El gaig canadenc és un ocell de la família dels còrvids (Corvidae) que habita boscos de coníferes de l'oest i centre d'Alaska, la major part de Canadà des de Yukon, cap a l'est, fins al nord de Labrador i Terranova, i als Estats Units per les dos vessants de les Muntanyes Rocalloses.
En diverses llengües rep el nom de "gaig canadenc" (Francès: Mésangeai du Canada. Espanyol: Arrendajo canadiense).
Aderyn a rhywogaeth o adar yw Sgrech lwyd (sy'n enw benywaidd; enw lluosog: sgrechod llwydion) a adnabyddir hefyd gyda'i enw gwyddonol Perisoreus canadensis; yr enw Saesneg arno yw Grey jay. Mae'n perthyn i deulu'r Brain (Lladin: Corvidae) sydd yn urdd y Passeriformes.[1]
Talfyrir yr enw Lladin yn aml yn P. canadensis, sef enw'r rhywogaeth.[2]
Mae'r sgrech lwyd yn perthyn i deulu'r Brain (Lladin: Corvidae). Dyma rai o aelodau eraill y teulu:
Rhestr Wicidata:
rhywogaeth enw tacson delwedd Aderyn rhisgl Falcunculus frontatus Aradrbig Eulacestoma nigropectus
.JPG)
Aderyn a rhywogaeth o adar yw Sgrech lwyd (sy'n enw benywaidd; enw lluosog: sgrechod llwydion) a adnabyddir hefyd gyda'i enw gwyddonol Perisoreus canadensis; yr enw Saesneg arno yw Grey jay. Mae'n perthyn i deulu'r Brain (Lladin: Corvidae) sydd yn urdd y Passeriformes.
Talfyrir yr enw Lladin yn aml yn P. canadensis, sef enw'r rhywogaeth.
Sojka šedá (Perisoreus canadensis) je asi 29 cm velký druh pěvce z čeledi krkavcovitých (Corvidae). Žije v severoamerických tajgách a subalpinských lesích, vyhledává přitom jedlové a borovicové porosty. Je převážně šedá se světlejším hrdlem a tmavým zobákem, temenem, zátylkem, křídly, ocasem a končetinami.[2][3]
Sojka šedá (Perisoreus canadensis) je asi 29 cm velký druh pěvce z čeledi krkavcovitých (Corvidae). Žije v severoamerických tajgách a subalpinských lesích, vyhledává přitom jedlové a borovicové porosty. Je převážně šedá se světlejším hrdlem a tmavým zobákem, temenem, zátylkem, křídly, ocasem a končetinami.
Der Meisenhäher (Perisoreus canadensis) ist ein Singvogel aus der Familie der Rabenvögel (Corvidae). Die Art bewohnt mit zahlreichen Unterarten die boreomontanen Nadelwälder des nördlichen Nordamerikas. Sie legt wie die beiden anderen Arten der Gattung Nahrungsvorräte an und lebt ganzjährig in festen Revieren.
Meisenhäher sind langschwänzige Häher mit flaumigem Gefieder und einem kurzen Schnabel, eine Haube fehlt. Die Tiere haben eine Körperlänge von etwa 29 cm. Rücken, Oberflügel und die Oberseite des Schwanzes sind dunkelgrau. Die Spitzen und die Außenfahnen von Schwingen, Schirmfedern und Flügeldecken sind in je nach Unterart variablem Umfang weißlich bis hell bläulich gesäumt, die Steuerfedern haben schmale weißliche Endsäume. Die Unterseite des Rumpfes ist einfarbig weißlich oder bläulich grau. Eine dunkelgraue Kopfzeichnung ist je nach Unterart auf den Nacken beschränkt oder erstreckt sich bis auf den mittleren Oberkopf und bis zum Oberrand der Augen, der übrige Kopf ist weiß. Schnabel und Beine sind schwarz. Vögel im Jugendkleid sind bei allen Unterarten fast einfarbig aschgrau mit nur einem undeutlichen weißen Bartstreif.[1]
Der Meisenhäher ist vom nördlichen Alaska nach Osten bis nach Neufundland und Labrador sowie nach Süden bis in das nördliche Kalifornien, Idaho, Utah, in das zentralöstliche Arizona, ins nördliche New Mexico, in das zentrale Colorado und bis in den Südwesten South Dakotas verbreitet. Er lebt auch ganzjährig im nördlichen Minnesota, Nordwisconsin, Nordmichigan, Nord-New York, und im nördlichen Neuengland. Er wandert mitunter in Gebiete nördlich seines Brutareals. Im Winter zieht er unregelmäßig ins nordwestliche Nebraska, zentrale Minnesota, südöstliche Wisconsin, zentrale Michigan, südliche Pennsylvania, zentrale New York, nach Connecticut und Massachusetts.[2][3][4]
Der Meisenhäher bildet zusammen mit dem Unglückshäher (P. infaustus) und dem Sichuanhäher (P. internigrans) die holarktisch verbreitete Gattung Perisoreus. Insgesamt werden elf Unterarten anerkannt.[4]
Der Meisenhäher (Perisoreus canadensis) ist ein Singvogel aus der Familie der Rabenvögel (Corvidae). Die Art bewohnt mit zahlreichen Unterarten die boreomontanen Nadelwälder des nördlichen Nordamerikas. Sie legt wie die beiden anderen Arten der Gattung Nahrungsvorräte an und lebt ganzjährig in festen Revieren.
The Canada jay (Perisoreus canadensis), also known as the gray jay, grey jay, camp robber, or whisky jack, is a passerine bird of the family Corvidae. It is found in boreal forests of North America north to the tree line, and in the Rocky Mountains subalpine zone south to New Mexico and Arizona. A fairly large songbird, the Canada jay has pale grey underparts, darker grey upperparts, and a grey-white head with a darker grey nape. It is one of three members of the genus Perisoreus, a genus more closely related to the magpie genus Cyanopica than to other birds known as jays. The Canada jay itself has nine recognized subspecies.
Canada jays live year-round on permanent territories in coniferous forests, surviving in winter months on food cached throughout their territory in warmer periods. The birds form monogamous mating pairs, with pairs accompanied on their territories by a third juvenile from the previous season. Canada jays adapt to human activity in their territories and are known to approach humans for food, inspiring a list of colloquial names including "lumberjack", "camp robber", and "venison-hawk". The International Union for Conservation of Nature (IUCN) considers the Canada jay a least-concern species, but populations in southern ranges may be affected adversely by global warming.
The species is associated with mythological figures of several First Nations cultures, including Wisakedjak, a benevolent figure whose name was anglicized to Whiskyjack. In 2016, an online poll and expert panel conducted by Canadian Geographic magazine selected the Canada jay as the national bird of Canada, although the designation is not formally recognized.
In 1760 the French zoologist Mathurin Jacques Brisson included a description of the Canada jay in his Ornithologie based on a specimen collected in Canada. He used the French name Le geay brun de Canada and the Latin Garralus canadensis fuscus.[2] Although Brisson coined Latin names, these do not conform to the binomial system and are not recognised by the International Commission on Zoological Nomenclature.[3] When in 1766 the Swedish naturalist Carl Linnaeus updated his Systema Naturae for the twelfth edition, he added 240 species that had been previously described by Brisson.[3] One of these was the Canada jay. Linnaeus included a brief description, coined the binomial name Corvus canadensis and cited Brisson's work.[4]
William John Swainson named it Dysornithia brachyrhyncha in 1831.[5] French ornithologist Charles Lucien Bonaparte assigned the Canada jay to the genus Perisoreus in 1838 in A geographical and comparative list of the birds of Europe and North America, along with the Siberian jay, P. infaustus.[6] The Canada jay belongs to the crow and jay family Corvidae. However, it and the other members of its genus are not closely related to other birds known as jays; they are instead close to the genus Cyanopica, which contains the azure-winged magpie.[7] Its relatives are native to Eurasia, and ancestors of the Canada jay are thought to have diverged from their Old World relatives and crossed Beringia into North America.[8]
A 2012 genetic study revealed four clades across its range: a widespread "boreal" or "taiga" clade ranging from Alaska to Newfoundland and ranging south to the Black Hills of South Dakota, Wyoming and Utah in the west and New England in the east, a "transcascade" clade in eastern Washington and Oregon and ranging into Alberta and Montana, a "Rocky Mountains (Colorado)" clade from the southern Rocky Mountains, and a "Pacific" clade from coastal British Columbia, Washington, and southwestern Oregon. There was also a population of the boreal clade in the central Rocky Mountains between the Colorado and transcascade clades. Genetic dating suggests the Pacific clade diverged from the common ancestor of the other clades around three million years ago in the Late Pliocene.[8]
The boreal clade is genetically diverse, suggesting that Canada jays retreated to multiple areas of milder climate during previous ice ages and recolonized the region in warmer times.[8]
In 2018 the common name was changed from grey jay to Canada jay by the American Ornithological Society in a supplement to their Check-list of North American Birds.[9] This change was also made in the online list of world birds maintained on behalf of the International Ornithologists' Union by Frank Gill and David Donsker.[10]
Nine subspecies are recognized:[11][10]
Two additional subspecies were formerly recognized:
The Canada jay is a relatively large songbird, though smaller than other jays. A typical adult Canada jay is between 25 and 33 cm (9.8 and 13.0 in) long. Its wingspan is around 45 cm (18 in). It weighs about 65 to 70 g (2.3 to 2.5 oz). Adults have medium grey back feathers with a lighter grey underside. Its head is mostly white with a dark grey or black nape and hood, with a short black beak and dark eyes. The long tail is medium grey with lighter tips.[19] The legs and feet are black.[20] The plumage is thick, providing insulation in the bird's cold native habitat.[21] Like most corvids, Canada jays are not sexually dimorphic, but males are slightly larger than females. Juveniles are initially coloured very dark grey all over, gaining adult plumage after a first moult in July or August.[22] The average lifespan of territory-owning Canada jays is eight years;[21] the oldest known Canada jay banded and recaptured in the wild was at least 17 years old.[22]
A variety of vocalizations are used and, like other corvids, Canada jays may mimic other bird species, especially predators. Calls include a whistled quee-oo, and various clicks and chuckles. When predators are spotted, the bird announces a series of harsh clicks to signal a threat on the ground, or a series of repeated whistles to indicate a predator in the air.[21]
The Canada jay's range spans across northern North America, from northern Alaska east to Newfoundland and Labrador, and south to northern California, Idaho, Utah, east-central Arizona, north-central New Mexico, central Colorado, and southwestern South Dakota. It is also found in the northern reaches of the states of Minnesota, Wisconsin, Michigan, the Adirondacks in New York, and New England. The Canada jay may wander north of the breeding range. In winter it travels irregularly to northwestern Nebraska, central Minnesota, southeastern Wisconsin, central Michigan, southern Pennsylvania, central New York, Connecticut, and Massachusetts.[12][23] Fossil evidence indicates the Canada jay was found as far south as Tennessee during the last ice age.[24]
The vast majority of Canada jays live where there is a strong presence of black spruce (Picea mariana), white spruce (P. glauca), Engelmann spruce (P. engelmannii), jack pine (Pinus banksiana), or lodgepole pine (P. contorta). Canada jays do not inhabit the snowy, coniferous, and therefore seemingly appropriate Sierra Nevada of California where no spruce occur. Nor do Canada jays live in lower elevations of coastal Alaska or British Columbia dominated by Sitka spruce (Picea sitchensis). The key habitat requirements may be sufficiently cold temperatures to ensure successful storage of perishable food and tree bark with sufficiently pliable scales arranged in a shingle-like configuration that allows Canada jays to wedge food items easily up into dry, concealed storage locations. Storage may also be assisted by the antibacterial properties of the bark and foliage of boreal tree species. An exception to this general picture may be the well-marked subspecies P. c. obscurus. It lives right down to the coast from Washington to northern California in the absence of cold temperatures or the putatively necessary tree species.[23]
The Canada jay typically breeds at two years of age. Monogamous, pairs remain together for life, though a bird will pair up with a new partner if it is widowed.[23] Breeding takes place during March and April, depending on latitude,[23][25][26] in permanent, all-purpose territories.[23][25][26][27] Second broods are not attempted, perhaps allowing greater time for food storage.[23][25]
Breeding is cooperative.[26][28][29] During the nest-building phase of the breeding season, Canada jay breeding pairs are accompanied by a third, juvenile bird. A 1991 field study in Quebec and Ontario found that approximately 65% of Canada jay trios included a dominant juvenile from the pair's previous breeding season, and approximately 30% of trios included non-dominant juveniles who had left their parents' territory. Occasionally, two nonbreeding juveniles accompany a pair of adults. The role of juveniles is in allofeeding (food sharing) by retrieving caches and bringing food to younger siblings,[28][29] but this is only allowed by the parents during the post-fledgling period.[26][28][29] Until then, parents will drive the other birds away from the nest. This may reduce the frequency of predator-attracting visits to the nest when young are most vulnerable. The benefits of juveniles participating in subsequent brood care may include "lightening the load" for the breeding pair, which may possibly increase longevity, reducing the probability of starvation of nestlings, and detecting and mobbing predators near the nest.[28] Dominant juveniles may eventually inherit the natal territory and breed, while unrelated juveniles may eventually fill a vacancy nearby or form a new breeding pair on previously unoccupied ground.[26]
Breeding Canada jays build nests and lay eggs in March or even February, when snow is deep in the boreal forest.[23][25] Male Canada jays choose a nest site in a mature conifer tree;[27] the nests are found most commonly in black spruce, with white spruce and balsam fir (Abies balsamea) also used, in Ontario and Quebec.[23][25] With the male taking a lead role in construction,[23] nests are constructed with brittle dead twigs pulled off of trees, as well as bark strips and lichens. The cup is just large enough to contain the female and her eggs,[21] measuring about 3 in (76 mm) wide and 2 in (51 mm) deep.[22] Insulation is provided by cocoons of the forest tent caterpillar (Malacosoma disstria) filling the interstitial spaces of the nest, and feathers used to line the cup.[22][23] Nests are usually built on the southwestern side of a tree for solar warming and are usually less than one nest diameter from the trunk.[25] Nest height is typically 8 to 30 ft (2.4 to 9.1 m) above the ground.[25] The average height of 264 nests surveyed in Algonquin Provincial Park was 16 ± 9.2 ft (4.9 ± 2.8 m) above ground.[25]
A clutch consists of 2 to 5 light green-grey eggs with darker spots.[20] The mean clutch sizes of Canada jays in Algonquin Provincial Park and La Verendrye Provincial Park were 3.03 and 3.18 eggs, respectively. Incubation is performed only by the female[25] and lasts an average of 18.5 days.[23] The female is fed on the nest by her partner, rarely moving from the nest during incubation and for several days after hatching.[25]
Canada jay young are altricial. For the first three to four days after hatching, the female remains on the nest; when the male arrives with food, both parents help in feeding the nestlings.[25] Nestling growth is most rapid from the fourth through the tenth day following hatching, during which time the female begins to participate in foraging. The parents carry food to the nest in their throats.[23][25] The accompanying nonbreeding third bird does not help with feeding during this period but is driven away by the parents if it approaches the nest.[28][29] Food is a dark brown, viscous paste containing primarily arthropods.[23][25] Young Canada jays leave the nest between 22 and 24 days after hatching, after which the third bird begins to participate in foraging and feeding.[23] Natal dispersal distance for the Canada jay is a median of 0.0 km for males, 2.8 km (1.7 mi) for females, and a maximum distance of 11.3 km (7.0 mi) for males and females.[26]
After 55 to 65 days, juveniles reach full adult measurements and battle among themselves until a dominant juvenile forces its siblings to leave the natal area.[30] The dominant bird remains with its parents until the following season, while its siblings leave the natal territory to join an unrelated pair who failed to breed. In a study by Dan Strickland, two-thirds of dominant juveniles were male.[26]
In studies conducted in Ontario and Quebec, the mortality rate for dominant juveniles was 52%, and mortality was 85% for juveniles who left the parents' territory between fledging in June to approximately mid-October. From fall to the following breeding season in March, further juvenile mortality was 50%. Territory-holding adult Canada jays experienced low mortality rates (15.1 and 18.2% for males and females, respectively).[26] The oldest known Canada jay recaptured in the wild was at least 17 years old.[22]
Canada jays are omnivorous.[23][25] They hunt such prey as arthropods,[23] small mammals including rodents,[31] and nestling birds,[32][33][34] and have even been recorded taking a magnolia warbler (Dendroica magnolia) in flight.[35] They have been reported to opportunistically hunt young amphibians such as the western chorus frog (Pseudacris triseriata) in Chambers Lake, Colorado,[36] and the long-toed salamander (Ambystoma macrodactylum) in Whitehorse Bluff in Crater Lake National Park, Oregon.[37] Canada jays have been seen landing on moose (Alces alces) to remove and eat engorged winter ticks (Dermacentor albipictus) during April and May in Algonquin Provincial Park. Researchers also found a Canada jay nest containing a brooding female, three hatchlings, and three warm, engorged winter deer ticks. Because the ticks were too large for the hatchlings to eat, it was hypothesized that the ticks may have served as "hot water bottles", keeping hatchlings warm when parents were away from the nest.[38]
Nestling birds are common prey,[34][39] being taken more often from nests in trees rather than on the ground.[32] Canada jays find them by moving from perch to perch and scanning surroundings.[23] Avian nest predation by Canada jays is not necessarily higher in fragmented versus unfragmented forest.[32][33][34] Evidence from studies in the Pacific Northwest suggest a moderate increase in nest predation in logged plots adjacent to mature conifer forest, which is the Canada jay's preferred habitat.[23][25] Studies of nest predation by Canada jays in Quebec have shown that the birds prefer preying on nests in open forest with high prominence of jack pine,[32] and greater rates of predation in riparian forest strips and green-tree retention stands versus clearcuts.[40] This may be due to increased availability of perch sites for avian predators such as the Canada jay.[34] Canada jays are suspected but not proven to prey on nests of the threatened marbled murrelet (Brachyramphus marmoratus) in coastal areas of the Pacific Northwest.[39]
Carrion,[23][25] fungi,[23] fruits such as chokecherry (Prunus virginiana),[25] and seeds[25] are also eaten. Two Canada jays were seen eating slime mold (Fuligo septica) near Kennedy Hot Springs in the Glacier Peak Wilderness, Washington. This was the first report of any bird consuming slime mold in the field.[41] Risk and energy expenditure are factors in food selection for the Canada jay, which selects food on the basis of profitability to maximize caloric intake. Increased handling, searching, or recognition times for a preferred food item lowers its profitability.[42] Canada jays wrench, twist, and tug food apart, unlike other birds known as jays (such as the blue jay, Cyanocitta cristata), which grasp and hammer their food.[22] Canada jays commonly carry large food items to nearby trees to eat or process for storage, possibly as defense against large scavengers.[23]
The Canada jay is a "scatterhoarder", caching thousands of food items during the summer for use the following winter,[42] and enabling the species to remain in boreal and subalpine forests year round.[23] Any food intended for storage is manipulated in the mouth and formed into a bolus that is coated with sticky saliva, adhering to anything it touches.[43] The bolus is stored in bark crevices, under tufts of lichen, or among conifer needles. Cached items can be anything from carrion to bread crumbs.[25] A single Canada jay may hide thousands of pieces of food per year, to later recover them by memory, sometimes months after hiding them.[25] Cached food is sometimes used to feed nestlings and fledglings.[25]
When exploiting distant food sources found in clearings, Canada jays were observed temporarily concentrating their caches in an arboreal site along the edge of a black spruce forest in interior Alaska. This allowed a high rate of caching in the short term and reduced the jay's risk of predation. A subsequent recaching stage occurred, and food items were transferred to widely scattered sites to reduce theft.[44]
Caching is inhibited by the presence of Steller's jays (Cyanocitta stelleri)[45] and Canada jays from adjacent territories,[46][47] which follow resident Canada jays to steal cached food.[45] Canada jays carry large food items to distant cache sites for storage more often than small food items. To prevent theft, they also tend to carry valuable food items further from the source when caching in the company of one or more Canada jays.[47] Scatterhoarding discourages pilferage by competitors, while increased cache density leads to increased thievery.[46] In southern portions of the Canada jay's range, food is not cached during summer because of the chance of spoilage and the reduced need for winter stores.[23]
Several bird species prey on Canada jays, including great grey owls (Strix nebulosa), northern hawk-owls (Surnia ulula),[48] and Mexican spotted owls (Strix occidentalis lucida).[49] Canada jay remains have been recovered from the lairs of fisher (Pekania pennanti) and American marten (Martes americana).[50] Red squirrels (Tamiasciurus hudsonicus) eat Canada jay eggs.[25] Canada jays alert each other to threats by whistling alarm notes, screaming, chattering, or imitating and/or mobbing predators.[23]
Found throughout Canada, the bird is popularly known by several colloquial names. One is "whisky jack",[21] a variation on the name of Wisakedjak, a benevolent trickster and cultural hero in Cree, Algonquin, and Menominee mythologies.[51] Alternate spellings for this name include wesakechak, wiskedjak, whiskachon, and wisakadjak.[52] The Tlingit people of northwestern North America know it as kooyéix or taatl'eeshdéi, "camp robber".[53] According to the Mi'kmaq of Nova Scotia, each of the seven stars of the Big Dipper depicted a different bird; the star Eta Ursae Majoris in the night sky was a Canada jay, Mikjaqoqwej.[54] In anishinaabemowin, or the Ojibwe language, the bird is known as gwiingwiishi.[55] "... the whisky jack is revered by indigenous peoples as an omen of good fortune and a warning of danger. Niigaanwewidam Sinclair, an associate professor and acting head of the department of native studies at the University of Manitoba, explained why the mischievous yet wise grey jay is important to the Anishinaabe people. "To my people, the Anishinaabe, she is Gwiingwiishi", Sinclair said in a post published by Canadian Geographic magazine. "Gwiingwiishi is a great, wise teacher, and there is an old story that tells of her abilities to give gifts... Her lesson? That it is only in our bravery, resilience and commitments to one another that we can find growth", Sinclair said.[56]
The Canada jay readily capitalizes on novel food sources, including taking advantage of man-made sources of food. To the frustration of trappers using baits to catch fur-bearing animals or early travelers trying to protect their winter food supplies, and to the delight of campers, bold Canada jays are known to approach humans for treats and to steal from unattended food stores. Canada jays do not change their feeding behaviour if watched by people;[42] if they are able to link humans with food, they will not forget. A nesting female that had become accustomed to being fed by humans was reportedly able to be enticed to leave the nest during incubation and brooding.[25] This behaviour has inspired a number of nicknames for the Canada jay, including "lumberjack", "meat-bird", "venison-hawk", "moose-bird", and "gorby",[21][57] the last two popular in the northeastern United States. The origin of "gorby", also spelt "gorbey", is unclear but possibly derived from gorb, which in Scottish Gaelic or Irish means "glutton" or "greedy (animal)" or in Scots or northern English "fledgling bird".[58] Superstition in Maine and New Brunswick relates how woodsmen would not harm gorbeys, believing that whatever they inflicted on the bird would be done to them. A folk tale circulated about a man who plucked a gorbey of its feathers and woke up the next morning having lost all his hair. Although the story was widespread in the early to mid-20th century, it does not appear to have been extant in 1902.[58]
In January 2015, The Royal Canadian Geographical Society's magazine, Canadian Geographic, announced a project to select a national bird for Canada, a designation which the country has never formally recognized.[59] Dubbed the National Bird Project, the organization conducted an online poll inviting Canadians to vote for their favourite bird.[60] The poll closed on 31 August 2016, and a panel of experts convened the following month to review the top five selections: the Canada jay, common loon (Gavia immer), snowy owl (Bubo scandiacus), Canada goose (Branta canadensis) and black-capped chickadee (Poecile atricapillus).[61] The project announced on 16 November 2016 that the Canada jay was selected as the winner of the contest.[62][63] Organizers hoped for the Canadian government to formally recognize the result as part of Canada's sesquicentennial celebrations in 2017; the Department of Canadian Heritage responded that no new official symbol proposals were being considered at the time.[64]
Canada jays are classified as least concern (LC) according to the IUCN Red List,[1] having stable populations over a very large area of boreal and subalpine habitats only lightly occupied by humans. Significant human impacts may nevertheless occur through anthropogenic climate warming. Canada jays at the northern edges of their range may benefit from the extension of spruce stands out onto formerly treeless tundra. A study of a declining population at the southern end of the Canada jay's range linked the decline in reproductive success to warmer temperatures in preceding autumns.[65] Such warm temperatures may trigger spoilage of the perishable food items stored by Canada jays upon which success of late winter nesting partly depends.[66]
This article incorporates public domain material from Perisoreus canadensis. United States Department of Agriculture.
The Canada jay (Perisoreus canadensis), also known as the gray jay, grey jay, camp robber, or whisky jack, is a passerine bird of the family Corvidae. It is found in boreal forests of North America north to the tree line, and in the Rocky Mountains subalpine zone south to New Mexico and Arizona. A fairly large songbird, the Canada jay has pale grey underparts, darker grey upperparts, and a grey-white head with a darker grey nape. It is one of three members of the genus Perisoreus, a genus more closely related to the magpie genus Cyanopica than to other birds known as jays. The Canada jay itself has nine recognized subspecies.
Canada jays live year-round on permanent territories in coniferous forests, surviving in winter months on food cached throughout their territory in warmer periods. The birds form monogamous mating pairs, with pairs accompanied on their territories by a third juvenile from the previous season. Canada jays adapt to human activity in their territories and are known to approach humans for food, inspiring a list of colloquial names including "lumberjack", "camp robber", and "venison-hawk". The International Union for Conservation of Nature (IUCN) considers the Canada jay a least-concern species, but populations in southern ranges may be affected adversely by global warming.
The species is associated with mythological figures of several First Nations cultures, including Wisakedjak, a benevolent figure whose name was anglicized to Whiskyjack. In 2016, an online poll and expert panel conducted by Canadian Geographic magazine selected the Canada jay as the national bird of Canada, although the designation is not formally recognized.
La Griza garolo aŭ Kanada garolo, Perisoreus canadensis, estas birdo membro de la familio de korvoj kaj garoloj nome Korvedoj kiu troviĝas en la borealaj arbaroj tra Nordameriko norde de la arbarlinio kaj en subalpaj arbaroj de la Roka Montaro sude ĝis Nov-Meksiko kaj Arizono. Ĝi estas unu el la tri membroj de la genro Perisoreus, la aliaj estas la Siberia garolo, P. infaustus, kiu troviĝas el Norvegio al orienta Rusio kaj montras ruĝecajn partojn en flugilo kaj vosto kaj la Siĉuana garolo, P. internigrans, kiu estas pli malhela kaj estas limigita ene de la montaroj de orienta Tibeto kaj nordokcidenta Siĉuano. La tri specioj stokas manĝaĵojn kaj loĝas la tutan jaron en konstantaj teritorioj en koniferaj arbaroj.
Kvankam la Griza garolo povas ŝveligi sian densan plumaron kaj ŝajnigi la impreson de grando, ĝi estas fakte unu el la plej malgrandaj garoloj de la mondo; maskloj pezas ĉirkaŭ 76 gm kaj inoj nur ĉirkaŭ 68 gm. Ambaŭ seksoj tipe havas helgrizajn subajn partojn, mezgrizajn suprajn partojn kaj parte nigran malantaŭan kapon kontraste kun tre blankaj frunto, vizaĝo kaj kolo. Estas nigraj la okuloj kaj la mallonga beko. La ekzempleroj de la marbordo de Pacifiko de Vaŝingtonio kaj Oregono havas pli da nigro ĉekape kaj pli rimarkindajn dorsojn kun videblaj blankaj strioj. Individuoj el la sudaj Rokaj Montoj havas nigrajn kapojn kiuj preskaŭ ne atingas la okulojn, kio havigas al la raso rimarkindan aspekton de pli blanka vizaĝo. Junuloj estas (ĝis aŭgusto) tute ardezgrizaj, kvankam iom pli malhelaj en la kapo.
Tiu nearktisa specio loĝas en plej granda parto de Kanado, escepte la nordaj kaj nordokcidentaj insuloj, en Alasko, en la nordokcidenta marbordo de Usono kaj en okcidenta Usono laŭ la Roka Montaro ĝis Nov-Meksiko. La pleja majoritato de la Griza garolo loĝas kie estas abundo de unu aŭ pliaj specioj de inter nigra piceo (Picea mariana), blanka piceo (P. glauca), englemana piceo (P. engelmanni), (Pinus banksiana) aŭ (P. contorta). Grizaj garoloj ne loĝas la neĝan, koniferan, kaj ŝajne taŭgan Sierra Nevada de Kalifornio kie estas nek piceoj nek unu el la du menciitaj pinoj. La Grizaj garoloj ankaŭ ne loĝas en malaltaj altitudoj de marborda Alasko aŭ Brita Kolumbio kie hegemonias la Sitka-piceo (Picea sitchensis). La ĉefa postularo pri habitato povas esti sufiĉe malvarmaj temperaturoj kiuj certigu sukcesan stokadon de putriĝebla manĝaĵo kaj arboŝelo kun sufiĉa skvamaro kiu permesu la Grizajn garolojn lokigi manĝerojn en precizaj kaj facile troveblaj sekaj lokoj. Stokado povas esti helpata de antibakteriaj propraĵoj de la arboŝelo kaj foliaro de la borealaj arbospecioj. Escepto al tiu ĝenerala bildo povas esti la tre markita subspecio P. c. obscurus, kiu iam ricevis la separatan specifan statuson kiel la “Oregona garolo”. Ili loĝas la tutan marbordon el Vaŝingtonio al norda Kalifornio kie ne estas malvarmaj temperaturoj aŭ la necesaj arbospecioj. Oni povas spekulacii ke tio dependas multe malpli de la stokebla manĝaĵo ol ĉe la aliaj pli tipaj rasoj de la Griza garolo. Mapoj ne montras tion, se la Griza garolo troviĝas ankaŭ en la Blanka Montaro de Nov-Hampŝiro.
Grizaj garoloj vivas en paroj, kiuj defendas po konstantan teritorion de 25 al 100 ha kontraŭ najbaroj. Ofte paro estas akompanata de tria ekzemplero nome junulo, kutime la hegemonia individuo el la plej ĵusa ovodemetado, sed foje nerilata enmigranto. La paro aŭ trio (rare kvaro) moviĝas tra la arbaro kiel izolita grupo, traserĉanta la ĉirkaŭaĵon por manĝo kaj vigle defende el predantoj.
Grizaj garoloj konstruas novan neston ĉiujare dum trisemajna periodo komence en februaro aŭ frua marto. La strukturo estas granda, fortika platformo de bastonetoj surhavanta internan neston de strioj de arboŝeloj, likenoj kaj plumoj. La ino demetas 2 al 5, sed plej ofte 3 aŭ 4 verdecajn grizajn ovojn kun brunecaj makuletoj je intervaloj de 26 horoj. La ino sursidiĝas post la demeto de la unua ovo (ŝajne por eviti ties frostigon) kaj komencas la veran kovadon nur post la demeto de la lasta ovo, sekurigante ke la tuta idaro eloviĝos en malmultaj horoj. Tipa demetado de 3 ovoj postulas kovado de 20 tagoj el la unuaovo al la eloviĝo. La ino sidiĝas tre streĉe dum tiu tempo sed ŝi estas manĝigata de la masklo nur unufoje tage. La idoj estas rozkoloraj kaj nudaj escepte maldensa dorsa lanugo. La masklo faras la tutan komencan manĝigadon dum la ino ekakompanas lin nur kiam la idoj estas jam unusemajnaĝaj. Post du semajnoj la idoj estas jam plumigitaj kaj estas ofte lasataj sole dum unu horo aŭ plie inter la gepatraj vizitoj. La junuloj kutime elnestiĝas post 23 tagoj. Ili kapablas ekflugi sed pasas plej parton de sia tempo kunigitaj atende manĝon kaj nur laŭgrade ekakompanas la plenkreskulojn. La vostoj estas jam plenaj kiam ili estas 42-45 tagaj, kiam ili jam estas lertaj flugantoj kaj ne estas manĝigataj plu de la gepatroj.
La manĝo estas precipe de kvar kategorioj: insektoj kaj araneoj, beroj kaj fungoj, birdidojn aŭ aliaj etaj vivintaj animaloj kiel musoj aŭ bufoj kaj kadavraĵo. Grizaj garoloj ne kapablas malfermi semojn de koniferoj kaj ne rilatas al borealaj pinsemoj. Kvankam iom da manĝo estas manĝata rekte, multaj individuaj eroj aŭ pecoj estas kovritaj el glua salivo kaj kaŝitaj en miloj da individuaj kaŝejoj alte en arboj, ofte en ŝelofendoj. Tiuj manĝostokejoj ebligas la Grizan garolon eviti la danĝerojn de la migrado kaj havi jaran survivan indicon ĉe plenkreskuloj (ĉ. 80 %) multe pli granda ol plej aliaj kompareblaj laŭgrando etaj birdoj. Surprize, plej da mortoj de Grizaj garoloj okazas ne en akra kaj ŝajne senmanĝa boreala vintro, sed somere, probable pro migrantaj birdomanĝantaj akcipitroj.
Grizaj garoloj pretas adaptiĝi al novaj manĝoresursoj inklude homojn vivantajj aŭ preterpasantajn siajn teritoriojn. Multaj individuaj Grizaj garoloj rapide lernas ke homoj povas esti eksterordinara manĝoresurso kaj eĉ venas al la mano por pano, vinberoj aŭ fromaĝo. Tia familiareco inspiris surloke longan liston de kromaj familiaj nomoj por la Griza garolo. Krom la iam oficiala ‘Kanada garolo,’ estas “viandomanxgulo”, “kamporabulo”, “musobirdo” kaj alia devena el algonkina mitologio.
Grizaj garoloj estas disvastigataj en boreala kaj subalpa habitatoj nur iome okupita de homoj. Tamen povas okazi ŝanĝoj pro antropogenia klimata varmigo. Grizaj garoloj de la nordaj bordoj de sia teritorio povas profiti el la etendo de piceoj en iama senarba tundro. Publikita studio dokumentis malpliiĝon en la suda bordo de la teritorio de la Griza garolo tamen kaj eble ligita al loka malpliiĝo en produktiveco pro pli varmaj temperaturoj en antaŭaj aŭtunoj. Tiaj varmaj temperaturoj povas akceli la perdon de putriĝeblaj manĝeroj stokitaj de Griza garolo el kio dependas la subtenon de la venontaj idaroj.
Estas tri surprizaj karakteroj de la reproduktado kaj socia kutimaro de la Griza garolo kiu levigas interesajn konsiderojn al la centraj konceptoj de la evolua biologio, nome ke la kutimaro de specio povas plisukcesigi la produkton de survivonta idaro.
Reproduktanta Griza garolo konstruas neston kaj demetas ovojn marte aŭ eĉ februare, kiam neĝo estas ankoraŭ profunda en la boreala arbaro kaj temperaturoj povas malsupreniri sub frostigo kaj ne estas evidente manĝaĵo por reproduktado. Spite tiom malamika vivkondiĉaro, Grizaj garoloj havas altan indicon de reprodukta sukceso kaj la junuloj tipe lasas la neston en frua aprilo, tre multe antaŭ la reveno de plej parto de boreala birdoj kiuj migris suden, kaj ekvivas solaj. Strange la Griza garolo neniam faras duan ovodemetadon en la sama sezono eĉ kvankam estus probable sufiĉe da tempo por fari tion kaj produkti pli da idoj jare ol ili faras. Stokita manĝaĵo permesas reproduktantajn garolojn manĝigi siajn idojn eĉ dum invernego sed tio klarigas nur kiel Grizaj garoloj povas elturniĝi kun idaro pasintan vintron kaj neniel kontribuas al komprenigo kial estas avantaĝa fari tion. Inter aliaj eblaj profitoj frue reproduktantaj Grizaj garoloj kiu faris tion frue povas investi pli da barakto por manĝostokado en siaj teritorioj antaŭ la venonta vintro. Supozo ke multe de la stokita manĝo daŭras ĝis alveno de malvarmaj temperaturoj, stokado de pli da manĝo en la teritorio signifus, ke frue reproduktantaj garoloj havas pli bonan eblon survivi la longan ŝajne senmanĝan borealan vintron hejme kaj evite danĝerojn de migrado. Tio povus signifi ke malmultaj idoj estas produktitaj ĉiun reproduktan sezonon (malpli ol ĉu la reproduktado okazus en junio) sed signifas ankaŭ ke se frue reproduktantaj Grizaj garoloj vivas pli longe kaj reproduktas pli ofte, ili povas ankaŭ produkti pli da survivontaj idoj longtempe ol se ili rereproduktiĝus aŭ reproduktiĝus pli malfrue en la sezono).
Kiam junaj Grizaj garoloj forlasas la neston en frua aprilo, ili kuniĝas por varmo unue kaj poste laŭgrade ekmoviĝas tra la arbaro kiel parto de adhera familigrupo. Tiam, kiam ili estas ĉirkaŭ 55tagaĝaj (5 semajnojn for de la nesto) ili ekluktemas inter ili kaj post dek tagoj, unu el ili forpelas la frataron el la naskiĝteritorio. La hegemonia junulo pluakompanos sian gepatrojn tra la unuaj aŭtuno kaj vintro (kaj foje plu), profitante ties sperton kaj protekton. La forpelita frataro foje sukcesas trovi ne sukcesan paron kiu toleras ilin sed plej parto malsukcesas kaj ĉirkaŭ 80 % el ili mortas pro malvarmo (kompare kun 50 % de la hegemoniaj junuloj kiuj restas hejme kun siaj gepatroj). Ĉar frataro kunhavas 50 % de la genaro (tiom kiom patro kunhavas kun sia idaro) oni bezonas klarigon por tiu kutimaro kiu rezultas en alta mortindico de individuaj gefrataroj.
Ĉe la Griza garolo ebla klarigo koncernas la problemon de stokado de sufiĉa manĝo por la unua vintro de juna birdo. Kvankam junuloj de Griza garolo ekstokas manĝaĵojn kiam ili estas nur kelkaj semajnoj aĝaj, ili preskaŭ certe ne estas lertaj kaj eble bezonas patran subtenon por eviti malsatomorton dum malvarmo. Se tiel, kaj de la patra subteno sufiĉas por la certa survivo de nur unu kroma birdo, estus bazo por konflikto por decido pri kiu ido estu la ununura profitonto. La demando tiam iĝas ‘kial ne atendi ĝis neĝofalo antaŭ forpeli la plej malfortajn idojn?’ Tiele la hegemonia junulo povus profiti ne nur sian propran manĝostokaĵojn (kaj ĝi estas kutime masklo ĉar estas pli grandaj kaj kutime venkas en disigaj luktoj), sed ankaŭ la manĝostokaĵojn kiujn la tutan someron faris la forpelontaj fratoj.
La precipa konsidero estas kiel oni akiras la patran subtenon. Se Grizaj garoloj trovas stokitajn manĝaĵojn per hazarda serĉado, forpeli idaron ĉu komence ĉu fine de la someraŭtuna stokosezono estus senefika. Por certigi tion la hegemonia junulo evitu ke la plej malfortaj fratoj akompanu la familigrupon sed ĝi malmulte povas fari por malhelpi ilin ŝtelserĉi la tre forstan teritorion kaj trovi stokitajn manĝaĵojn per si mem. Se Grizaj garoloj rekovras stokitan manĝaĵon danke al memoro, tamen, la hegemonia junulo bezonas liberigi sin el konkurenco komence de la stokosezono. Tiele la plej malforta frataro neniam scios kie estas kaŝita la stokita manĝaĵo kaj ne povos resti en la patra teritorio. Male ili spertos intereson post malvenko en la lukto kontraŭ la hegemonia frato eliri serĉi alian teritorion solece kaj eventuale eblon esti tolerata de alia loka paro. Farinte tion ili havu almenaŭ luktan eblon akiri vintran manĝohelpon per si mem. La fakto ke hegemoniaj junuloj forpelas sian frataron junie je la komenco de la stokosezono kaj la fakto ke forpelitaj junuloj rekte foriras kaj klopodas akiri akcepton el nerilataj paroj sugestas, ke la Griza garolo rekuperas stokomanĝon per memoro.
Kiam Grizaj garoloj ekkonstruas siajn nestojn februare aŭ marte, 20 % aŭ plie de ĉiuj paroj estas ankoraŭ akompanataj de tria individuo nereproduktanta kaj kutime la hegemonia junulo el la ĵuspasinta idaro de la paro. Ankaŭ multaj aliaj birdospecioj, ĉefe en tropikoj, kaj elstare inklude garolojn, pluhavas junulojn kiuj ne kapablis trovi teritoriojn per si mem. Ĝenerale helpantoj de tiaj birdospecioj helpas manĝigi la novan idaron de siaj propraj gepatroj kaj partoprenas en la defendo de la nesto. En multaj kazoj tia helpo ŝajne plibonigas la produkton de survivantoj. La kroma junulo tiele pligrandigas la eblon de disvastigo de siaj propraj genoj en la venonta generacio, kvazaŭ same kiel se ĝi estus havinta idaron de si mem.
Ĉe Grizaj garoloj tamen nereproduktuloj ne helpas siajn gepatrojn zorgi sian pli junan idaron. Anstataŭe ili kutime restaa for de la nesto kaj se ili alproksimiĝas, la plenkreskuloj energie forpelas ilin. Sed, se helpo de nereproduktuloj estas tiom profita por aliaj birdoj kun simila demografia cirkunstancaro, kial ne ĉe Grizaj garoloj? Estus pli grava por birdo kiu nestumas en malvarmo, ŝajne senmanĝa kondiĉaro de frua vintro. Eĉ pli konfuziga, kvankam paro malhelpas ke la nereproduktulo manĝigu la idaron, ili permesos tian manĝigadon kiam la junuloj jam forlasis la neston. Tiu stranga maligo de konduto povus esti klarigata jene. Unue kromaj flugoj al nesto kun manĝaĵoj povus esti danĝeraj se ili havigas la lokon al predanto kiu ne estus facile forpelata eĉ de la barakto kambine de la paro kaj la nereproduktulo. Tion certigas la fakto ke plenkreskuloj de Griza garolo helpas ankaŭ pluhavi la neston nevideblan per sistemo de alporto de maksimuma manĝokvanto per minimuma flugokvanto. Due, se la nestopredanto kiu estas kaŭzo de tia konduto estas mamulo, estos malpli danĝere kiam la junulo jam flugas kaj elnestiĝis. Tio povus klarigi kial post la elnestiĝo reproduktantaj Grizaj garoloj ekpermesas manĝovizitojn al la juna nereproduktulo kaj ankaŭ kial ili mem ekfaras pli oftajn vizitojn (kun malpli da manĝokvanto).
La Griza garolo aŭ Kanada garolo, Perisoreus canadensis, estas birdo membro de la familio de korvoj kaj garoloj nome Korvedoj kiu troviĝas en la borealaj arbaroj tra Nordameriko norde de la arbarlinio kaj en subalpaj arbaroj de la Roka Montaro sude ĝis Nov-Meksiko kaj Arizono. Ĝi estas unu el la tri membroj de la genro Perisoreus, la aliaj estas la Siberia garolo, P. infaustus, kiu troviĝas el Norvegio al orienta Rusio kaj montras ruĝecajn partojn en flugilo kaj vosto kaj la Siĉuana garolo, P. internigrans, kiu estas pli malhela kaj estas limigita ene de la montaroj de orienta Tibeto kaj nordokcidenta Siĉuano. La tri specioj stokas manĝaĵojn kaj loĝas la tutan jaron en konstantaj teritorioj en koniferaj arbaroj.
El arrendajo canadiense (Perisoreus canadensis)[1] es una especie de ave paseriforme de la familia Corvidae propia de Norteamérica. Es un pájaro común de los bosques fríos norteamericanos, puede encontrarse en los bosques boreales desde el límite del bosque septentrional a los bosques subalpinos de las Montañas Rocosas, llegando por el sur hasta de Nuevo México y Arizona. Es uno de los tres miembros del género Perisoreus. Las tres especies almacenan alimentos y viven durante todo el año en los territorios permanente en los bosques de coníferas.
El arrendajo canadiense (Perisoreus canadensis) es una especie de ave paseriforme de la familia Corvidae propia de Norteamérica. Es un pájaro común de los bosques fríos norteamericanos, puede encontrarse en los bosques boreales desde el límite del bosque septentrional a los bosques subalpinos de las Montañas Rocosas, llegando por el sur hasta de Nuevo México y Arizona. Es uno de los tres miembros del género Perisoreus. Las tres especies almacenan alimentos y viven durante todo el año en los territorios permanente en los bosques de coníferas.
Perisoreus canadensis Perisoreus generoko animalia da. Hegaztien barruko Corvidae familian sailkatua dago.
Perisoreus canadensis Perisoreus generoko animalia da. Hegaztien barruko Corvidae familian sailkatua dago.
Harmaakuukkeli (Perisoreus canadensis)[2] on varisten heimoon kuuluva varpuslintu.
Harmaakuukkeli on 29 cm pitkä, se painaa keskimäärin 70 grammaa ja sen siipiväli on 45 cm. Harmaakuukkeli on vaaleanharmaa, pitkäpyrstöinen ja lyhytnokkainen lintu. Ulkonäössä on suurta vaihtelua populaatioiden välillä. Kaikien populaatioiden aikuisilla yksilöillä on kuitenkin mustat silmät, nokka ja jalat sekä valkoinen korvalaikku ja kurkku.[3]
Harmaakuukkelia tavataan Kanadassa ja Yhdysvalloissa.[1]
Harmaakuukkelit elävät tavallisimmin kuusi- ja pihtametsissä. Ne ovat syrjäisten metsien lintuja, eivätkä elä vakituisen ihmisasutuksen läheisyydessä.[1]
Harmaakuukkeli on kaikkiruokainen ja käyttää ravinnokseen esimerkiksi niveljalkaisia, marjoja, raatoja, linnunmunia ja -poikasia sekä sieniä.[1]
Harmaakuukkeli (Perisoreus canadensis) on varisten heimoon kuuluva varpuslintu.
Perisoreus canadensis
Le Mésangeai du Canada (Perisoreus canadensis) est communément appelé geai du Canada ou geai gris. En anglais, il est également connu sous les noms de « whisky jack » et de « camp robber ».
En 2016, une compétition organisée par le magazine Canadian Geographic a sélectionné le Mésangeai du Canada comme oiseau national du pays. Cette distinction n'est pas reconnue officiellement par le gouvernement[1],[2].
Cet oiseau peut mesurer de 23 à 35 cm de long. Ses plumes peuvent atteindre une longueur de 6 cm. La Mésangeai du Canada peut vivre 19 ans.
Il se rencontre du nord du Canada et de l'Alaska jusqu'à la limite d'expansion des forêts boréales et subalpines du centre du Québec et du nord de la Californie, de l'Arizona et du Nouveau-Mexique dans les Rocheuses, au nord du Wisconsin dans le Midwest et dans l'État de New York à l'est.
Le mésangeai du Canada est omnivore, il se nourrit de baies, d'arthropodes, de vers, de charognes, d'oisillons, d'œufs et de petits mammifères (musaraignes, campagnols, et chauves-souris juvéniles)[3].
Il n'est pas farouche envers les humains et vient volontiers quémander ou chaparder de la nourriture dans les camps de bûcherons, auprès des chasseurs ou des randonneurs[4].
Cette espèce est monogame. En début février le mâle choisit l'emplacement du nid et commence à le construire. La femelle le rejoint ensuite pour l'aider. Le nid mesure entre 14 et 16 cm de diamètre. La femelle y dépose 2 à 4 œufs gris-verts entre fin-mars début-avril, à raison d'un par jour. Elle les couve pendant 18 à 19 jours. Pendant cette période elle se fait nourrir par le mâle pour ne pas avoir à quitter le nid. Lors de l'éclosion, la femelle aide les petits à sortir en cassant la coquille des œufs avec son bec. A la naissance les petits pèsent de 4,5 à 7 g. La femelle leur tient chaud et le mâle défend le nid contre les prédateurs. Les petits peuvent s'envoler au bout de 17 à 23 jours. Ils sont totalement indépendant entre 55 et 66 jours. Ils restent néanmoins sur le territoire de leurs parents jusqu'à trouver un partenaire sexuel. Ils atteignent la maturité sexuelle entre 1 et 2 ans[3].
Les principaux prédateurs des petits sont l'écureuil roux américain et la petite buse. Les adultes peuvent être la proie de l'autour des palombes, la chouette tachetée, le faucon pèlerin, le faucon émerillon et la buse à queue rousse[3].
Perisoreus canadensis
Le Mésangeai du Canada (Perisoreus canadensis) est communément appelé geai du Canada ou geai gris. En anglais, il est également connu sous les noms de « whisky jack » et de « camp robber ».
En 2016, une compétition organisée par le magazine Canadian Geographic a sélectionné le Mésangeai du Canada comme oiseau national du pays. Cette distinction n'est pas reconnue officiellement par le gouvernement,.
Is éan Pasaireach é an Scréachóg Liath. Is mícháiliúil an scréachóg í mar go bhfuil sí cliste chun na gada. Is minic an scréachóg liath bia a ghoid. Uaireanta íosfainn an scréachóg liath as láimh duine.
Cruthaíonn an scréachóg liath stór bia leis a smaois.
Tá an scréachóg liath le fáil in Alasca, Ceanada agus Stáit Aontaithe Mheiriceá.
Is é an t-éan náisiúnta i gCeanada.
Aitheantas
Aithnítear an scréachóg seo as a cleite clúmhach liath agus a cochall dubh. Tá gearr-gob dubh uirthi. Níl cochall dubh uirthi áfach nuair atá sí anabaí.
Eitlíonn sí le cosán preabach agus foluain ghearr.
Tá guth aclaí aici le feadaíl bhog agus maolgháire. Déanann sí aithris as éin eile lena guth.[1]
Is éan Pasaireach é an Scréachóg Liath. Is mícháiliúil an scréachóg í mar go bhfuil sí cliste chun na gada. Is minic an scréachóg liath bia a ghoid. Uaireanta íosfainn an scréachóg liath as láimh duine.
Cruthaíonn an scréachóg liath stór bia leis a smaois.
Tá an scréachóg liath le fáil in Alasca, Ceanada agus Stáit Aontaithe Mheiriceá.
Is é an t-éan náisiúnta i gCeanada.
Aitheantas
Aithnítear an scréachóg seo as a cleite clúmhach liath agus a cochall dubh. Tá gearr-gob dubh uirthi. Níl cochall dubh uirthi áfach nuair atá sí anabaí.
Eitlíonn sí le cosán preabach agus foluain ghearr.
Tá guth aclaí aici le feadaíl bhog agus maolgháire. Déanann sí aithris as éin eile lena guth.
La ghiandaia grigia canadese (Perisoreus canadensis (Linnaeus, 1766)) è un uccello passeriforme della famiglia dei corvidi[2].
Misura 27-31 cm di lunghezza, per 50-85 g di peso e 45 cm di apertura alare[3]: a parità d'età, i maschi sono lievemente più grossi delle femmine[3]. Le dimensioni medie, inoltre, tendono a crescere in direttrice S-N, e forse anche dalla costa verso l'interno dell'areale[3].
Si tratta di uccelli dall'aspetto robusto e massiccio, muniti di grossa testa squadrata con becco conico e di media lunghezza, ali appuntite, coda piuttosto lunga e dall'estremità arrotondata e zampe forti.
Il piumaggio è bianco su fronte, gola, guance, lati del collo e petto, dove sfuma nel grigio topo, colore questo che ricopre ventre e fianchi, mentre sul sottocoda esso si schiarisce nel grigio-biancastro: dorso, ali e coda sono di color grigio scuro, con quest'ultima e le remiganti più scure e tendenti al nerastro. Vertice e nuca sono invece di colore nero, così come la tempia, fino alla parte superiore dell'occhio.
Sussiste una certa variabilità intraspecifica nella colorazione, a livello di estensione e tonalità del bianco cefalotoracico e del nero cefalico (che può arrivare a ricoprire anche la nuca) e della tonalità del grigio dorsale e ventrale (che può mostrare sfumature color cannella o rosato).
Il becco e le zampe sono di color grigio-nerastro: gli occhi, invece, sono di colore bruno scuro, con cerchio perioculare nudo e di colore nero-violaceo.
Si tratta di uccelli dalle abitudini di vita diurne, che vivono da soli o in coppie, talvolta riunendosi in gruppi temporanei in corrispondenza di fonti di cibo particolarmente abbondanti (carcasse di grossi animali, grossi alberi in frutto, piantagioni): essi passano la maggior parte della giornata alla ricerca di cibo sul suolo della foresta, posandosi di tanto in tanto su qualche conifera (in genere un peccio o un abete balsamico) dove si riscaldano tenendo la testa sotto un'ala[4]. Lo stesso risultato può essere ottenuto facendo bagni di sole con le ali semiaperte nei giorni freddi ma soleggiati.
Le coppie tendono a occupare territori di 27-137,5 ettari (più piccoli se il cibo è abbondante, ad esempio se sono presenti mangiatoie), che difendono da eventuali intrusi soprattutto durante i mesi più freddi, immediatamente prima della riproduzione: all'apparire di un estraneo, le ghiandaie canadesi schioccano nervosamente il becco e tengono la testa abbassata (comportamento aggressivo comune a molti corvidi), salvo poi volargli incontro ed inseguirlo in volo fino a quando non ha lasciato il territorio. Talvolta, tali comportamenti aggressivi vengono indirizzati anche ai partner, con lo scopo di sottrarre loro il cibo.
Si tratta di uccelli piuttosto silenti, ed anche i loro versi sono bassi: questi vanno da cinguettii più o meno acuti per comunicare col partner a lunghi ed aspri fischi acuti per segnalare un pericolo aereo, fino a corte note basse per segnalare invece un pericolo proveniente da terra. La ghiandaia canadese è inoltre una buona imitatrice dei versi di altri uccelli.
La ghiandaia grigia canadese è un uccello onnivoro, che si nutre indifferentemente di cibo di origine animale o vegetale a seconda della disponibilità, prediligendo comunque la prima componente. Questi uccelli si nutrono a vista, avendo un senso dell'olfatto piuttosto poco sviluppato, portando il cibo su un albero prima di consumarlo.
Una preda piuttosto comune della ghiandaia grigia sono le uova e soprattutto i nidiacei dei piccoli uccelli (fra i quali anche la minacciata urietta marmorizzata[5])[6]: in un singolo caso, un esemplare attaccò e uccise in volo una dendroica della magnolia, per poi consumarla[7]. Fra gli altri animali consumati vi sono i girini di rane[8] e salamandre[9], topolini[10], lucertole, insetti ed altri invertebrati: questi uccelli sono inoltre stati osservati mentre estraevano delle zecche dalla pelle degli alci similmente a quanto fanno le bufaghe, e in alcuni casi conservarle ancora calde nei propri nidi, probabilmente per riscaldare i nidiacei[11]. La ghiandaia grigia canadese si ciba inoltre della carne, del grasso e delle larve rinvenute nelle carcasse, a patto che esse siano state già sventrate da altri predatori, in quanto il becco di questi uccelli non è strutturato in maniera tale da poter incidere la pelle.
Fra i cibi di origine vegetale consumati da questi uccelli vi sono una varietà di bacche e frutti, nonché di funghi (fra cui il fungo mucillaginoso Fuligo septica, unici fra gli uccelli a consumarlo[12]), granaglie e semi.
La ghiandaia canadese, similmente a molti corvidi, ha l'abitudine di disseminare il cibo in eccesso in numerosi nascondigli sparsi per il proprio territorio durante i periodi di abbondanza, in modo tale da poter usufruire di una cospicua riserva di cibo durante i mesi freddi[13]: il cibo da conservare viene manipolato e inumidito con la saliva appiccicosa a formare un bolo, che viene poi appiccicato nella spaccatura di una corteccia, sotto un lichene o fra le fronde di una conifera[14][15].
L'accumulo di scorte di cibo (che permette a questi uccelli di riprodursi durante l'inverno e di non dover migrare[16][17]) è inibito dalla presenza di altri corvidi (soprattutto la ghiandaia di Steller) o di altri individui di territori adiacenti, i quali possono attendere che l'animale si allontani per depredarne la riserva[18].
Si tratta di uccelli monogami, le cui coppie una volta formatesi rimangono insieme per la vita (tranne nel caso in cui uno dei coniugi perisca, dando modo all'altro di trovare un nuovo compagno), riproducendosi una volta l'anno fra marzo e maggio.
Durante la riproduzione, le coppie vengono aiutate da individui adulti non riproduttivi, in genere giovani (nella maggior parte dei casi uno, ma a volte anche due) nati durante la stagione riproduttiva precedente: questi aiutanti vengono accettati durante le fasi di costruzione del nido e di cure parentali ai nidiacei dopo l'involo, mentre durante la cova ed il periodo nidicolo dei nuovi nati essi vengono tenuti lontani dal nido[19]. I giovani aiutanti, oltre a fare esperienza che tornerà loro utile quando sarà il loro turno di riprodursi, ereditano il territorio dalla coppia riproduttiva che hanno aiutato[20].
Il nido viene costruito fra i 2 e i 9 metri d'altezza nel folto dei rami di una grossa conifera, molto vicino al tronco e solitamente orientato verso sud-ovest per ottenere più sole possibile durante la giornata: la sua costruzione è quasi interamente a carico del maschio, che edifica una struttura a coppa piuttosto piccola fatta di germogli secchi, fibre vegetali e licheni, tenuta assieme con ragnatela e bozzoli di Malacosoma disstria.
All'interno del nido la femmina depone 2-5 uova di colore verdino chiaro, con rade maculature più scure: esse vengono covate dalla sola femmina per circa 18 giorni, col maschio che si occupa di reperire il cibo per sé e per la compagna e di tenere d'occhio i dintorni del nido.
I pulli sono ciechi ed implumi alla schiusa: essi vengono imbeccati da ambedue i genitori, con la femmina che non si allontana dal nido per i primi tre giorni dopo la schiusa, ma li imbecca con parte del cibo che il maschio reperisce e rigurgita.
I piccoli cominciano a tentare l'involo a partire dalle tre settimane di vita: a questo punto cominciano ad essere imbeccati anche dagli aiutanti, raggiungendo la taglia adulta attorno ai due mesi dalla schiusa.
Una volta divenuti virtualmente indipendenti, i nidiacei cominciano una serie di combattimenti fra loro, per delineare una gerarchia che determinerà quali saranno gli aiutanti della coppia riproduttrice l'anno successivo (solo uno o due dei giovani dominanti saranno ammessi a fare ciò) e quali, invece, dovranno lasciare il territorio natio, allontanandosi di 2-10 km (con le femmine che solitamente si disperdono andando più lontano rispetto ai maschi[21]) ed aggregandosi ad altre coppie non riproduttive[22].
La speranza di vita di questi uccelli è di 8 anni, tuttavia singoli esemplari sono vissuti per oltre 17 anni allo stato selvatico.
Come intuibile sia dal nome comune che dal nome scientifico, la ghiandaia grigia canadese è diffusa in Nordamerica settentrionale, dall'Alaska settentrionale al Labrador (mancando dalla punta settentrionale del Québec e dalle coste del Nunavut), oltre che a Terranova e sull'isola d'Anticosti, a sud fino all'estremità settentrionale della California, al Nuovo Messico centro-settentrionale, al Dakota del Sud sud-occidentale, al nord del New England e alla Nova Scotia.
Si tratta di uccelli sedentari, che al massimo possono scendere di quota durante l'inverno per sfuggire al freddo montano: soprattutto i giovani in dispersione possono compiere modesti spostamenti, divenendo avvistabili anche più a nord o a sud dell'areale di diffusione. Durante l'ultima era glaciale, inoltre, questi uccelli erano diffusi anche nell'est degli Stati Uniti, a sud fino al Tennessee[23].
L'habitat di questi uccelli è rappresentato dalle pinete a prevalenza di peccio (soprattutto peccio nero e peccio bianco, ma anche peccio di Engelmann, pino contorto e pino di Banks, nonché dal peccio Sitka nel nord dell'areale): sebbene la ghiandaia canadese popoli anche le foreste miste di conifere e latifoglie (soprattutto pioppo ed acero), essa è particolarmente legata ai pecci (la cui corteccia rugosa e la resina dalle proprietà antibatteriche sono ideali per la conservazione del cibo per lunghi periodi), tanto da risultare assente da ambienti che per il resto sembrerebbero ideali per le sue esigenze, come la Sierra Nevada e gli Appalachi.
Se ne riconoscono 9 sottospecie[2]:
Alcuni autori riconoscerebbero inoltre le sottospecie barbouri dell'isola d'Anticosti (sinonimizzata con nigricapillus[24]) e arcus delle coste della Columbia Britannica (sinonimizzata con obscurus)[3].
Esemplare della sottospecie pacificus sul Denali.
Esemplare della sottospecie nominale nel distretto di Nipissing.
Esemplare della sottospecie albescens nell'Alberta.
Esemplare della sottospecie capitalis nel Wyoming.
Esemplare della sottospecie obscurus sul monte Hood.
Le sottospecie sono differenziabili in quattro cladi[25]:
La ghiandaia canadese è un uccello molto conosciuto e benvoluto nel suo areale di residenza: è ben nota la confidenza che questi uccelli hanno con l'uomo, imparando velocemente a prendere il cibo dalle mani o a sottrarlo agli incauti turisti e campeggiatori.
Questa loro abitudine di rubare il cibo ha dato origine a molti dei nomi comuni di questi uccelli: in inglese questi uccelli sono noti coi nomi di whisky jack (derivato dalla figura del trickster Wisakedjak, comune nella mitologia di Cree, Menominee e Algonchini) o gorby/gorbey (da gorb, "ghiottone" in scots e irlandese[26]), mentre in tlingit essi vengono chiamati kooyéix o taatl'eeshdéi ("ladro")[27].
Per la loro indole scanzonata e confidente, le ghiandaie canadesi sono tuttavia molto benvolute: fra i Micmac (per i quali ciascuna delle stelle del Grande Carro rappresenta una specie di uccello), essi sono incarnati in Mikjaqoqwej (Alkaid), mentre fra i coloni del New England era diffusa durante il XIX secolo la superstizione secondo la quale qualsiasi danno subito da questi uccelli sarebbe stato subito da colui che l'ha inferto (celebre la storia secondo la quale un boscaiolo che spennò una ghiandaia canadese si svegliò calvo il mattino seguente)[26].
Nel 2015, il Canadian Geographic lanciò un sondaggio per scegliere l'uccello nazionale del Canada: tale sondaggio, chiuso l'anno seguente, vide la ghiandaia grigia sbaragliare la concorrenza (rappresentata da strolaga maggiore, civetta delle nevi, cincia testanera e oca canadese), senza peraltro essere insignito dell'ufficialità da parte del governo canadese[28].
La ghiandaia grigia canadese (Perisoreus canadensis (Linnaeus, 1766)) è un uccello passeriforme della famiglia dei corvidi.
Kanādas bēdrozis jeb pelēkais bēdrozis, arī pelēkais sīlis (Perisoreus canadensis) ir neliela auguma vārnu dzimtas (Corvidae) putns, kas sastopams visā Ziemeļamerikas ziemeļu boreālajā zonā. Izdala 9 pasugas.[1]
Kanādas bēdrozis sastopams gan ASV, gan Kanādā.[2] Dienvidos sastopams līdz Klinšu kalniem Ņūmeksikā un Arizonā. Kanādas bēdrozis galvenokārt sastopams egļu un priežu mežos, priekšroku dodot melno egļu (Picea mariana), Kanādas egļu (Picea glauca), Engelmaņa egļu (Picea engelmannii), Benksa priežu (Pinus banksiana) un Klinškalnu priežu (Pinus contorta) audzēm. Tas nav sastopams Britu Kolumbijas un Aļaskas rietumu piekrastes mežos, kuros aug Sitkas egles (Picea sitchensis).
Bēdrozis ir neliels vārnu dzimtas putns. Ķermeņa garums 25—33 cm, spārnu plētums 43—47 cm, svars 50—85 g.[3][4][5][6] Tas ir nedaudz mazāks vai vienāds ar savu radinieku Sibīrijas bēdrozi (Perisoreus infaustus) Eirāzijā.
Kā jau putna nosaukums norāda pelēkā bēdroža ķermeņa apspalvojums ir pelēkā krāsā; mugurspuse tumšāk pelēka, vēderpuse gaišāka. Tā piere, vaigi un pakakle ir balta, pakausis un kakla aizmugure melna. Tam ir īss, melns knābis un proporcionāli gara aste. Abi dzimumi izskatās vienādi.[7] Bēdroža apspalvojums ir biezs, kupls un mīksts, radot pūkainu iespaidu. Apspalvojums lieliski silda putnu aukstajās Kanādas naktīs, kad temperatūra var noslīdēt līdz –40°C.[8]
Lai arī Kanādas bēdrozis ir izteikti mazāks par zilo sīli (Cyanocitta cristata), tā siluets lidojumā ir pārsteidzoši līdzīgs. Tomēr bēdroža lidojums ir mazāk enerģisks un lēnāks, salīdzinot ar dienvidu kaimiņu. Tuvumā abus putnus sajaukt nevar.[8] Jaunie putni, kas tikko pametuši ligzdu, atšķiras no pieaugušajiem bēdrožiem. Tie ir viscauri, vienmērīgi tumši pelēki. Faktiski jaunie putni tik ļoti atšķiras no vecākiem, ka ilgstoši valdīja uzskats, ka tā ir cita putnu suga. Apspalvojumu jaunuļi maina jūlija beigās, bet augustā visi pelēkie bēdroži jau izskatās vienādi.[8]
Kanādas bēdrozis barību parasti aiznes uz kādu koka zaru, lai to tur apēstu vai noslēptu.[9] Lai noslēptu barību, tas nelielu kumosu savā mutē saspaida kopā ar siekalām bumbiņā. Bēdroža siekalas ir lipīgas, tādējādi kumosu var piestiprināt jebkurā vietā starp mizas krokām vai skujām, kā arī zaru plaisās un iedobēs.[10] Putni, kas uzkrāj barību, parasti dzīvo ilgāk kā citi putni.[11]
Bēdroža dabīgie ienaidnieki ir ziemeļpūce (Strix nebulosa), svītrainā pūce (Surnia ulula) un punktainā pūce (Strix occidentalis).[12] Tā atliekas ir atrastas arī zivju caunas (Martes pennanti) un Amerikas caunas (Martes americana) migās. Bet Amerikas rudā vāvere (Tamiasciurus hudsonicus) pie iespējas izēd bēdroža olas.[10] Ja Kanādas bēdrozis tuvumā pamana ienaidnieku, tas brīdina visus pārējos bēdrožus ar īpašu trauksmes saucienu un ķērkšanu, cenšoties plēsēju aizvilināt prom no ligzdas vai vienkārši tam uzbrūkot.[9]
Bēdrozis ir visēdājs, bet pie iespējas vienmēr dod priekšroku olbaltumvielām un taukiem bagātai barībai.[13] Tas parasti pārmeklē cilvēku pārpalikumus pikniku vietās. Ja Kanādas bēdrozis kaut reizi tiks pabarots, tas vēlāk vienmēr atpazīs cilvēku ar barību.[10]
Barojas ar maziem dzīvniekiem un putniem, maitas gaļu, sēklām, sēnēm, augļiem un ogām. Ir novērots, ka Kanādas bēdrozis ēd arī gļotsēnes (Fuligo septica). Tas ļoti bieži apēd citiem putniem mazos putnēnus un olas. Tas pārmeklē koku pēc koka, vērojot citus putnus.[9] Reizēm bēdrozis nosēžas uz aļņa muguras un pārmeklē tā kažoku, meklējot ērces.[14]
Kanādas bēdrozis dzimumbriedumu sasniedz 2 gadu vecumā. Pāri ir monogāmi un tie paliek kopā uz mūžu, bet, ja viens no pāra aiziet bojā, tiek veidots jauns pāris.[9] Ligzdot pelēkie bēdroži sāk martā vai aprīlī. Sezonā viens perējums. Dominantie jaunie putni padzen pakļāvīgākos brāļus un māsas, bet paši paliek kopā ar vecākiem līdz nākamajam gadam. Apmēram divas trešdaļas no "palicējiem" ir tēviņi.[15] Galvenais palicēju uzdevums ir aizsargāt teritoriju no ienaidniekiem un pēc tam, kad jaunās vasaras putnēni ir apspalvojušies un izlidojuši no ligzdas, tos barot.[15] Pirms tam vecāki pagājušās vasaras bērnus tuvumā pie ligzdas nelaiž.
Dējumā 2—5 olas. Tās ir gaiši zaļas ar olīvkrāsas raibumiņiem. Inkubācijas periods ilgst apmēram 18 dienas. Olas perē tikai mātīte, bet tēviņš to baro.[16] Putnēnus baro abi vecāki ar daļēji sagremotu barību.[17] Jaunie putni izlido 22—24 dienu vecumā. Piecu mēnešu vecumā tie sasniedz pieaugušu putnu augumu. Vidējais vecums ir 8 gadi.[4] Vecākā zināmā Kanādas bēdroža mātīta sasniegusi 16 gadu vecumu, bet tēviņš 14 gadu vecumu.
Kanādas bēdrozim ir 9 pasugas:[1]
Kanādas bēdrozis jeb pelēkais bēdrozis, arī pelēkais sīlis (Perisoreus canadensis) ir neliela auguma vārnu dzimtas (Corvidae) putns, kas sastopams visā Ziemeļamerikas ziemeļu boreālajā zonā. Izdala 9 pasugas.
De Canadese taigagaai (Perisoreus canadensis) is een zangvogel uit de familie Corvidae (kraaien).
Deze soort telt negen ondersoorten:
Gråskrike (Perisoreus canadensis) er den mest vanlige fuglen i barskogområdene i Alaska. Den kalles ofte «leirplassrøveren» fordi den alltid prøver seg på å stjele en liten matbit. I Canada blir den også kalt «Whisky Jack».
Denne ornitologirelaterte artikkelen er foreløpig kort eller mangelfull, og du kan hjelpe Wikipedia ved å utvide den. Gråskrike (Perisoreus canadensis) er den mest vanlige fuglen i barskogområdene i Alaska. Den kalles ofte «leirplassrøveren» fordi den alltid prøver seg på å stjele en liten matbit. I Canada blir den også kalt «Whisky Jack».
Multimedia w Wikimedia Commons Sójka kanadyjska (Perisoreus canadensis) – gatunek małego ptaka z rodziny krukowatych (Corvidae), występującego w tajdze Ameryki Północnej. Jest jednym z trzech gatunków należących do rodzaju Perisoreus. Jest blisko spokrewniony z sójką syberyjską (Perisoreus infaustus) oraz sójką okopconą (Perisoreus internigrans). Wyróżniono kilka podgatunków P. canadensis[4][2]:
Sójka kanadyjska (Perisoreus canadensis) – gatunek małego ptaka z rodziny krukowatych (Corvidae), występującego w tajdze Ameryki Północnej. Jest jednym z trzech gatunków należących do rodzaju Perisoreus. Jest blisko spokrewniony z sójką syberyjską (Perisoreus infaustus) oraz sójką okopconą (Perisoreus internigrans). Wyróżniono kilka podgatunków P. canadensis:
P. canadensis pacificus – środkowa Alaska do wybrzeży zachodnio-środkowej Kanady. sójka kanadyjska (P. canadensis canadensis) – północno-wschodnia Alaska i północno-zachodnia Kanada do wschodniej Kanady i północno-wschodniego USA. P. canadensis nigricapillus – północno-wschodni Quebec i Labrador. sójka blada (P. canadensis albescens) – wschodnie Góry Skaliste w zachodnio-środkowej Kanadzie i północno-środkowym USA. P. canadensis bicolor – Góry skaliste od południowo-wschodniej Kolumbii Brytyjskiej i południowo-wschodniej Alberty do wschodniego Waszyngtonu, Idaho i zachodniej Montany. sójka białogłowa (P. canadensis capitalis) – Góry Skaliste od południowego Idaho do Nowego Meksyku i Arizony. P. canadensis griseus – Góry Kaskadowe od południowo-wschodniej Kanady do północno-wschodniej Kalifornii. sójka białobrzucha (P. canadensis obscurus) – wybrzeża północno-zachodniego USA. P. canadensis sanfordi – Nowa Fundlandia.Grå lavskrika[2] (Perisoreus canadensis) är en fågel i familjen kråkfåglar inom ordningen tättingar.[3]
Den påträffas på tajgan i Nordamerika norrut till trädgränsen och i alpina områden strax under trädgränsen söderut till New Mexico och Arizona. Den är en ganska stor osciner och är blekt gå på undre delen, mörkare grå på den övre delen och har ett gråvitt huvud med mörkare grå nacke. Den är en av tre arter i släktet Perisoreus, som är ganska nära släkt med skatorna Cyanopica.
Grå lavskrika lever året runt i permanenta revir i barrskog. Under vintermånaderna lever de på mat som de har samlat under den varmare tiden. Fåglarna bildar monogama par. I reviret lever också ofta en ungfågel som paret har fött upp det föregående året. Grå lavskrika anpassar sig väl till mänsklig aktivitet i dess revir och kan närma sig människor för att få mat. IUCN betraktar arten som livskraftig, men populationer i den södra delen av utbredningsområdet kan komma att påverkas negativt av global uppvärmning.
Grå lavskrika delas in i nio underarter med följande utbredning som i sin tur utgör tre polytypiska grupper:[3]
Arten har ett stort utbredningsområde och en stor population med stabil utveckling.[1] Utifrån dessa kriterier kategoriserar IUCN arten som livskraftig (LC).[1]
Underarten. P. c. capitalis i Yellowstone.
Grå lavskrikor kan vara mycket orädda för människor.
Grå lavskrika häckar mycket tidigt på året.
Par som matar sin kull.
Ungfågel under första vintern. Juvenilen är gråfärgad.
Wikimedia Commons har media som rör grå lavskrika.
Wikispecies har information om Perisoreus canadensis.
Grå lavskrika (Perisoreus canadensis) är en fågel i familjen kråkfåglar inom ordningen tättingar.
Den påträffas på tajgan i Nordamerika norrut till trädgränsen och i alpina områden strax under trädgränsen söderut till New Mexico och Arizona. Den är en ganska stor osciner och är blekt gå på undre delen, mörkare grå på den övre delen och har ett gråvitt huvud med mörkare grå nacke. Den är en av tre arter i släktet Perisoreus, som är ganska nära släkt med skatorna Cyanopica.
Grå lavskrika lever året runt i permanenta revir i barrskog. Under vintermånaderna lever de på mat som de har samlat under den varmare tiden. Fåglarna bildar monogama par. I reviret lever också ofta en ungfågel som paret har fött upp det föregående året. Grå lavskrika anpassar sig väl till mänsklig aktivitet i dess revir och kan närma sig människor för att få mat. IUCN betraktar arten som livskraftig, men populationer i den södra delen av utbredningsområdet kan komma att påverkas negativt av global uppvärmning.
Wikimedia Commons'ta Perisoreus canadensis ile ilgili çoklu ortam belgeleri bulunur. 
Wikispecies'te Perisoreus canadensis ile ilgili detaylı taksonomi bilgileri bulunur. Perisoreus canadensis, kargagiller familyasından Kuzey Amerika taygalarında yaşayan alakarga türü. Alt türlerinin sayısı 11 dir. Yalnızca insanlar tarafından işgal edilen boreal ve subalpin habitatlarda görülür.
Perisoreus canadensis, kargagiller familyasından Kuzey Amerika taygalarında yaşayan alakarga türü. Alt türlerinin sayısı 11 dir. Yalnızca insanlar tarafından işgal edilen boreal ve subalpin habitatlarda görülür.
Ку́кша кан́адська[1] (Perisoreus canadensis) — птах роду кукша, поширений у зоні хвойних лісів Північної Америки. Птах близько споріднений із кукшами тайговою та китайською.
Канадська кукша запасає великі кількості поживи для пізнішого споживання. Своєю клейкою слиною вона приліплює маленькі шматочки корму до гілок вище рівня майбутнього снігового покриву. Вважається, що ця саме ця харчова поведінка дозволяє їй виживати протягом зимових місяців на північних територіях ареалу. Гніздовий період канадської кукші припадає на кінець зими. Вона висиджує яйця при температурах, які іноді падають до - 20°С. Як не дивно, кукша не має іншого гніздового періоду у травні-червні, коли це роблять інші птахи у бореальних лісах, незважаючи на більш сприятливі температурні умови для виведення потомства.[2]
Виділяють кілька підвидів кукші канадської:
Завдяки тому, що кукша канадська трапляється, хоч і не всюди, але практично в кожній провінції Канади, а також через її дружній норов, після певних дискусій її було номіновано національною пташкою Канади[3].
Це незавершена стаття з орнітології.Ку́кша кан́адська (Perisoreus canadensis) — птах роду кукша, поширений у зоні хвойних лісів Північної Америки. Птах близько споріднений із кукшами тайговою та китайською.
Канадська кукша запасає великі кількості поживи для пізнішого споживання. Своєю клейкою слиною вона приліплює маленькі шматочки корму до гілок вище рівня майбутнього снігового покриву. Вважається, що ця саме ця харчова поведінка дозволяє їй виживати протягом зимових місяців на північних територіях ареалу. Гніздовий період канадської кукші припадає на кінець зими. Вона висиджує яйця при температурах, які іноді падають до - 20°С. Як не дивно, кукша не має іншого гніздового періоду у травні-червні, коли це роблять інші птахи у бореальних лісах, незважаючи на більш сприятливі температурні умови для виведення потомства.
Виділяють кілька підвидів кукші канадської:
P. canadensis pacificus – поширена від центральної Аляски і до середніх широт канадського узбережжя Пацифіку; P. canadensis canadensis – від північного сходу Аляски і до північного заходу Канади і північно-східних районів США; P. canadensis nigricapillus – північно-східний Квебек i Лабрадор у Канаді; P. canadensis albescens – від східних відрогів Скелястих гір через середній захід Канади і північ центральної частини США; P. canadensis bicolor – від Скелястих гір через південно-східну частину Британськоїх Колумбії і північно-східну Альберту до східного Вашингтону, Айдаго і західної Монтани; P. canadensis capitalis – Скелясті гори від південного Айдахо до Нью-Мексико і Аризони; P. canadensis griseus – [Каскадні гори]] від південно-східної Канади до північно-східної Каліфорнії; P. canadensis obscurus – північно-західне узбережжя США; P. canadensis sanfordi – Ньюфаундленд.Завдяки тому, що кукша канадська трапляється, хоч і не всюди, але практично в кожній провінції Канади, а також через її дружній норов, після певних дискусій її було номіновано національною пташкою Канади.
Perisoreus canadensis là một loài chim trong họ Corvidae.[2] Quạ thông xám được tìm thấy trong khu rừng phía bắc của Bắc Mỹ Bắc vào dòng cây, và ở vùng Rocky Mountains cận núi cao ở phía nam New Mexico và Arizona. Đây là một loài chim biết hót khá lớn, quạ thông xám có phần dưới màu xám nhạt, trên lưng màu xám tối hơn, đầu màu xám-trắng với gáy xám sẫm. Nó là một trong ba thành viên của chi perisoreus, một chi nhỏ liên quan chặt chẽ hơn với chi cyanopica của Newcastle so với các loài chim khác được gọi là giẻ cùi. Quạ thông xám có chín phân loài được công nhận.
Quạ thông xám sinh sống quanh năm trên lãnh thổ vĩnh viễn trong rừng lá kim, còn sống sót trong những tháng mùa đông trên được lưu trữ thực phẩm trong suốt lãnh thổ của họ trong khoảng thời gian ấm áp hơn. Chúng tạo thành cặp giao phối một vợ một chồng, với cặp đi cùng trên lãnh thổ của họ bởi một người chưa thành niên thứ ba từ mùa giải trước. Quạ thông xám thích ứng với hoạt động của con người trong lãnh thổ của chúng và được biết đến để tiếp cận con người đối với thực phẩm. Liên minh Quốc tế Bảo tồn Thiên nhiên (IUCN) xem quạ thông xám một loài ít quan tâm; Tuy nhiên người dân trong phạm vi miền Nam có thể bị ảnh hưởng bởi biến đổi khí hậu.
Loài này được kết hợp với nhân vật thần thoại của nhiều nền văn hóa quốc gia đầu tiên, bao gồm Wisakedjak, một nhân vật nhân từ, với tên được Anh hóa thành Whiskyjack. Trong năm 2016, một cuộc thăm dò trên mạng và các chuyên gia được tiến hành bởi tạp chí Địa lý Canada chọn jay xám là loài chim quốc gia của Canada, mặc dù việc chỉ định không được chính thức công nhận.
Perisoreus canadensis là một loài chim trong họ Corvidae. Quạ thông xám được tìm thấy trong khu rừng phía bắc của Bắc Mỹ Bắc vào dòng cây, và ở vùng Rocky Mountains cận núi cao ở phía nam New Mexico và Arizona. Đây là một loài chim biết hót khá lớn, quạ thông xám có phần dưới màu xám nhạt, trên lưng màu xám tối hơn, đầu màu xám-trắng với gáy xám sẫm. Nó là một trong ba thành viên của chi perisoreus, một chi nhỏ liên quan chặt chẽ hơn với chi cyanopica của Newcastle so với các loài chim khác được gọi là giẻ cùi. Quạ thông xám có chín phân loài được công nhận.
Quạ thông xám sinh sống quanh năm trên lãnh thổ vĩnh viễn trong rừng lá kim, còn sống sót trong những tháng mùa đông trên được lưu trữ thực phẩm trong suốt lãnh thổ của họ trong khoảng thời gian ấm áp hơn. Chúng tạo thành cặp giao phối một vợ một chồng, với cặp đi cùng trên lãnh thổ của họ bởi một người chưa thành niên thứ ba từ mùa giải trước. Quạ thông xám thích ứng với hoạt động của con người trong lãnh thổ của chúng và được biết đến để tiếp cận con người đối với thực phẩm. Liên minh Quốc tế Bảo tồn Thiên nhiên (IUCN) xem quạ thông xám một loài ít quan tâm; Tuy nhiên người dân trong phạm vi miền Nam có thể bị ảnh hưởng bởi biến đổi khí hậu.
Loài này được kết hợp với nhân vật thần thoại của nhiều nền văn hóa quốc gia đầu tiên, bao gồm Wisakedjak, một nhân vật nhân từ, với tên được Anh hóa thành Whiskyjack. Trong năm 2016, một cuộc thăm dò trên mạng và các chuyên gia được tiến hành bởi tạp chí Địa lý Canada chọn jay xám là loài chim quốc gia của Canada, mặc dù việc chỉ định không được chính thức công nhận.
Perisoreus canadensis (Linnaeus, 1766)
Ареал
Канадская ку́кша[1], или канадская ронжа[1] (лат. Perisoreus canadensis) — североамериканская певчая птица семейства врановых.
Канадская кукша это длиннохвостая птица с пушистым оперением и коротким клювом, хохол отсутствует. Длина тела примерно 29 см. Спина, кроющие перья и верхняя сторона хвоста тёмно-серые. Вершины перьев в зависимости от подвида от белёсого до светло-синеватого цвета, у рулевых перьев имеется тонкая белёсая кайма. Нижняя сторона тела одноцветно белёсая или синевато-серая. Тёмно-серая макушка ограничена в зависимости от подвида затылком или простирается вплоть до глаз, остальная часть головы белая. Клюв и ноги чёрные. Оперение молодых птиц у всех подвидов почти одноцветное пепельно-серое с неотчётливой белой «бородкой»[2].
Канадская кукша распространена от северной Аляски на восток до Ньюфаундленда и Лабрадора, а также на юг вплоть до северной Калифорнии, Айдахо, Юты, в центрально-восточной Аризоне, в северном Нью-Мехико, в центральном Колорадо и вплоть до юго-запада Южной Дакоты. Она круглый год живёт в северной Миннесоте, северном Висконсине, северном Мичигане, северном Нью-Йорк и в северной части Новой Англии. Она мигрирует иногда в области к северу от своего гнездового ареала. Зимой она нерегулярно мигрирует в северо-западную Небраску, центральную Миннесоту, юго-восточный Висконсин, центральный Мичиган, южную Пенсильванию, центральный Нью-Йорк, в Коннектикут и Массачусетс[3][4][5].
Птенцов выводит зимой. Чтобы питаться в это время, две птицы делают осенью около 10 000 тайников с пищей[6].
11 подвидов канадской кукши обитают в хвойных лесах бореальной зоны Северной Америки[5].
Канадская ку́кша, или канадская ронжа (лат. Perisoreus canadensis) — североамериканская певчая птица семейства врановых.
灰噪鸦（学名：Perisoreus canadensis），是鸦科噪鸦属的一种，分布于加拿大和美国。全球活动范围约为7,300,000平方千米。该物种的保护状况被评为无危。
灰噪鸦的平均体重约为71.7克。栖息地包括温带森林和寒带森林。
灰噪鸦（学名：Perisoreus canadensis），是鸦科噪鸦属的一种，分布于加拿大和美国。全球活动范围约为7,300,000平方千米。该物种的保护状况被评为无危。
灰噪鸦的平均体重约为71.7克。栖息地包括温带森林和寒带森林。
分類 界 : 動物界 Animalia 門 : 脊索動物門 Chordata 亜門 : 脊椎動物亜門 Vertebrata 綱 : 鳥綱 Aves 目 : スズメ目 Passeriformes 科 : カラス科 Corvidae 属 : アカオカケス属 Perisoreus 種 : カナダカケス P. canadensis 学名 Perisoreus canadensisカナダカケス（学名：Perisoreus canadensis）は、スズメ目カラス科に分類される鳥類。
この項目は、鳥類に関連した書きかけの項目です。この項目を加筆・訂正などしてくださる協力者を求めています（ポータル鳥類 - PJ鳥類）。 
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