Setophaga kirtlandii (Baird & SF 1852)

Aderyn a rhywogaeth o adar yw Telor Kirtland (sy'n enw gwrywaidd; enw lluosog: telorion Kirtland) a adnabyddir hefyd gyda'i enw gwyddonol Dendroica kirtlandii; yr enw Saesneg arno yw Kirtland's warbler. Mae'n perthyn i deulu'r Telorion y Byd Newydd (Lladin: Paruliadae) sydd yn urdd y Passeriformes.^[1]

Talfyrir yr enw Lladin yn aml yn D. kirtlandii, sef enw'r rhywogaeth.^[2] Mae'r rhywogaeth hon i'w chanfod yng Ngogledd America.

Teulu

Mae'r telor Kirtland yn perthyn i deulu'r Telorion y Byd Newydd (Lladin: Paruliadae). Dyma rai o aelodau eraill y teulu:

Rhestr Wicidata:

Gweler hefyd

• Rhestr Goch yr IUCN

Cyfeiriadau

Der Michiganwaldsänger (Setophaga kirtlandii, Syn.: Dendroica kirtlandii) ist ein kleiner Vogel aus der Gattung der Baumwaldsänger (Setophaga) in der Familie der Waldsänger (Parulidae). Er gehört zu den seltensten nordamerikanischen Brutvögeln. Die IUCN stuft den Michiganwaldsänger als potentiell gefährdet (near threatened) ein.^[1]

Der erste bekannte Vogel wurde im Mai 1851 auf dem Bauernhof des Arztes und Naturwissenschaftlers Jared Potter Kirtland in Ohio erschossen. Kirtland war dieser Vogel völlig unbekannt und er schickte eine Probe an Spencer Fullerton Baird an das Smithsonian Institution. Als der Vogel von Baird als neue Art beschrieben wurde, benannte er ihn nach Kirtland.

Verbreitungsgebiet

Der Michiganwaldsänger hat eines der kleinsten kontinentalen Brutgebiete weltweit. Es umfasst maximal 516 Quadratkilometer und war zeitweise auf nur noch 18 Quadratkilometer geschrumpft.^[2] Das Brutgebiet liegt fast ausschließlich im US-amerikanischen Bundesstaat Michigan, nur gelegentlich brütet der Michiganwaldsänger auch im angrenzenden Teil von Kanada. Erst um 1900 wurden die Brutgebiete entdeckt, als zufällig Angler unbekannte Vogelstimmen hörten.

Zum Überwintern fliegt der Vogel auf die Bahamas. Michiganwaldsänger verlassen im August ihre Brutgebiete und kehren Mitte Mai wieder zurück. Als problematisch erweisen sich dabei die Habitatveränderungen im Überwinterungsgebiet. Allerdings wusste man lange nicht, wo genau der Michiganwaldsänger auf den Bahamas überwintert. Inzwischen hat man jedoch feststellen können, dass sich eine größere Zahl dieser Art auf der Insel Eleuthera einfindet. Zurzeit finden weitere Untersuchungen statt mit dem Ziel, die Hauptüberwinterungsgebiete dieser Art stärker zu schützen.^[3]

Lebensraum

Der hochspezialisierte Singvogel stellt große Anforderungen an seine Lebensräume. Er brütet nur am Boden junger Exemplare von Banks Kiefer (Pinus banksiana), einer Kiefernart, die ausschließlich im Norden von Nordamerika vorkommt. Im Idealfall handelt es sich um reine Bestände, die gewöhnlich nur auf Sandböden vorkommen. Die Banks-Kiefern dürfen noch nicht älter als 15 Jahre sein und zwischen zwei und vier Metern hoch sein. Wenn die Kiefer diese Größe erreicht haben, verlässt der Michiganwaldsänger den Bereich und ist auf der Suche nach einem jüngeren Baumbestand. Bei der Verbreitung des Michiganwaldsänger muss es noch weitere, bisher unbekannte Standortfaktoren geben, denn die Bankskiefer ist in Nordamerika weit verbreitet, der Michiganwaldsänger kommt jedoch nur in einem sehr kleinen Teil dieses Verbreitungsgebietes vor.^[4]

Mittlerweile weiß man, dass regelmäßige Flächenbrände in den Brutgebieten des Michiganwaldsängers notwendig sind, um die Art zu erhalten. Die Banks-Kiefer benötigt Feuer, um ihre Bestände zu verjüngen. Während bei einem Waldbrand die älteren Bäume vernichtet werden, öffnen die Kiefernzapfen sich nur bei einer Temperatur über fünfzig Grad Celsius und setzen ihre Samen frei. Diese können auf den dann frei gewordenen Flächen auskeimen und die jungen Bestände bilden, auf die der Michiganwaldsänger angewiesen ist. Heute werden in den Regionen, die der Michiganwaldsänger bewohnt, die Wälder gezielt bewirtschaftet und der Waldbrandeffekt simuliert, damit ausreichend Habitate für diesen Vogel zur Verfügung stehen.^[5]

Merkmale

Michiganwaldsänger erreichen eine Körperlänge von etwa 15 Zentimetern. Das Männchen hat ein blaugraues mit schwarzen Streifen durchsetztes Oberseitengefieder. Das Unterseitengefieder ist hellgelb und mit grauen bis schwarzen Streifen an den Flanken durchsetzt. Auf den Flügeldecken befinden sich zwei blasse weiße Flügelstäbe. Das Weibchen hat insgesamt ein stumpferes Federkleid. Um das Auge trägt der Michiganwaldsänger einen unterbrochenen weißen Augenring. Wenn der Vogel sitzt, wippt er mit seinem Endstück auf und ab.

Fortpflanzung

Das Männchen kommt zuerst in den Brutgebieten an. Im Normalfall besiedelt das Männchen das gleiche Brutgebiet wie im Vorjahr und fängt sofort an zu singen, um sein Territorium gegenüber anderen Artgenossen abzugrenzen und ein Weibchen anzulocken. Die Brutperiode beginnt im späten Mai und dauert bis Mitte Juni. Das aus Gräsern, Blättern, Moosen und Haaren erbaute schalenförmige Nest am sandigen Boden wird gemeinsam errichtet. Ein Gelege umfasst drei bis sechs Eier. Selten werden zwei Gelege in der Brutzeit ausgebrütet. Bei dem zweiten Brutvorgang enthält ein Gelege jedoch weniger Eier als beim ersten. Das Weibchen brütet die Eier alleine in einem Zeitraum von etwa 14 bis 15 Tagen aus. Die Jungen schlüpfen nach etwa zwölf bis dreizehn Tagen. An der Aufzucht beteiligen sich beide Altvögel. An den ersten fünf Tagen legen die Jungvögel rasch an Gewicht zu und verdoppeln danach alle zwei Tage ihr Gewicht.

Bedrohung und Schutz

Der Braunkopf-Kuhstärling (Molothrus ater) hat die Bestände des Michiganwaldsängers stark bedroht

Der Michiganwaldsänger war stark bedroht durch den Brutparasitismus des Braunkopf-Kuhstärlings (Molothrus ater). Als die Europäer Nordamerika besiedelten, wurden Wälder abgebrannt, um Weideflächen und weitere Nutzflächen zu gewinnen. Zuvor war der Braunkopf-Kuhstärling vorwiegend in den Prärien vorzufinden, wo er den großen Herden der Bisons folgte und die aufgewirbelten Samen und aufgescheuchten Insekten vertilgte. Durch die optimalen Bedingungen der Kolonisation vergrößerte er sein Verbreitungsgebiet in Nordamerika nördlich und südlich und siedelte sich in den neu geschaffenen Lebensräumen an. In den 60er Jahren wurden mehr als 70 % der Nester des Michiganwaldsängers von dem Braunkopf-Kuhstärling parasitiert. Durch ein Schutzprogramm wurden in den frühen 70er Jahren gezielt Braunkopf-Kuhstärlinge entlang des Streckenverlaufes getötet und die Lebensräume unter Schutz gestellt. Dadurch ist der Brutparasitismus unter 3 % zurückgegangen.

Jedes Jahr findet durch Freiwillige eine Zählung zwischen dem 6. Juni und dem 15. Juni statt. Dabei werden die singenden Männchen gezählt und mit zwei multipliziert. Die Zählungen erfolgten am Anfang nur in den Jahren 1951, 1961 und 1971 und wurden ab 1971 jährlich vorgenommen. Die Forscher gehen davon aus, dass den Vögeln andere Probleme während des Vogelzugs und in den Wintergebieten auf den Bahamas zu schaffen machen. Der Bestand des Michiganwaldsängers ist zwischen 1961 und 1971 auf etwa 60 % zurückgegangen. 1987 wurden nur noch 167 Männchen gezählt. Ab 1996 konnte ein langsames Ansteigen der Bestände nachgewiesen werden. Waren es 1996 noch 692 Männchen, so stieg die Zahl 1997 auf 733 und 1998 auf 805 an.

Quellen

Literatur

• Dominic Couzens: Seltene Vögel – Überlebenskünstler, Evolutionsverlierer und Verschollene. Haupt Verlag, Bern 2011, ISBN 978-3-258-07629-4.
• Jon Curson, David Quinn, David Beadle: New World Warblers. Helm, London 1994, ISBN 0-7136-3932-6.

Einzelnachweise

1. ↑ BirdLife Factsheet zum Michiganwaldsänger, aufgerufen am 5. August 2011
2. ↑ Couzon, S. 94
3. ↑ Couzon, S. 96
4. ↑ Couzon, S. 95
5. ↑ Couzon, S. 95–96

Kirtland's warbler (Setophaga kirtlandii), also known in Michigan by the common name jack pine bird,^[3][4] or the jack pine warbler, is a small songbird of the New World warbler family (Parulidae). Nearly extinct just 50 years ago, populations have recovered due to conservation efforts. It requires large areas, greater than 160 acres (65 hectares), of dense young jack pine for its breeding habitat. This habitat was historically created by wildfire, but today is created through the harvest of mature jack pine, and planting of jack pine seedlings.

The population of the species spends the spring and summer in their breeding range in the Great Lakes region of Canada (Ontario) and the United States (Wisconsin and Michigan, especially in the northeastern Lower Peninsula), and winters in the West Indies.

Taxonomy

This species was first recorded by Europeans relatively late for a bird from eastern North America.^[5] The first specimen was shot at sea somewhere between the Abaco Islands of The Bahamas and Cuba in mid-October 1841 by the ornithologist Samuel Cabot III. However, the specimen was unrecognized as a new species in the private collection of Cabot's father, Boston merchant Samuel Cabot Jr., until it made its way to the Museum of the Smithsonian Institution in the 1860s.^[6][7]

Ten years later the holotype, a juvenile male, was shot on Jared Potter Kirtland's farm near Cleveland, Ohio, in mid-May 1851.^[8] It was used to formally describe the species as Sylvicola kirtlandii by Spencer Fullerton Baird in 1852. Baird first attributed the collection to Charles Pease (Kirtland's son-in-law) in his 1852 description,^[8] but by 1858 he had changed his story and was attributing it to Kirtland.^[9][10]

In 1858 Baird moved the species, still then only known from his single specimen, to the genus Dendroica,^[9] where it remained until the 2010s, where it was reclassified into Setophaga.^[11]

By 1865 only four individuals were known to have been collected. Baird lists the male specimen from the Cabot collection, the holotype, a first female specimen shot in 1860 near Cleveland and preserved by R. K. Winslow, and a fourth (which Winslow mentioned had also been killed near Cleveland but had not been preserved).^[6] Local naturalist Philo Romayne Hoy also mentioned having possibly seen the species once near the village of Racine, Ohio, in the 1850s.^[9]

Etymology

Baird decided to name the bird after Jared Potter Kirtland: "a gentleman to whom, more than any one living, we are indebted for a knowledge of the Natural History of the Mississippi Valley".^[8] The generic epithet Setophaga is from the genitive case of Ancient Greek σής, transliterated as sḗs, meaning "moth", and phagos, meaning "eating".^[12]

Description

Female

Male Kirtland's warblers have bluish-grey upper body parts, with dark streaks on the back, yellow bellies, and dark streaks on the flanks and sides. It has black lores (cheeks) and a distinctive, large and conspicuous broken white eye ring,^[13][14] which it only shares with Setophaga coronata.^[14] Females and juveniles are similar, but are browner on the wings and back and are not as boldly or brightly marked. It frequently bobs its tail up and down, which is uncommon in northern warblers. At 14–15 cm (5.5–5.9 in)^[13] and 12.3–16 g (0.43–0.56 oz),^[15] it is the largest of the numerous warblers formerly classified in the genus Dendroica and is now the largest of the 35 or so species in the currently-accepted Setophaga genus.^[9] The Kirtland warbler has a wingspan of 22 cm (8.7 in).^[16] Its mating song is a loud chip-chip-chip-too-too-weet-weet often sung from the top of a snag (dead tree) or northern pin oak (Quercus ellipsoidalis) clump. This song can be heard over 400m away in good conditions.^[13] In its overwintering grounds it does not sing but makes loud "chip" noises from low in dense bushes.^[17]

The eggs are a "delicate" pinkish white when fresh, fading to a dull white after a time. There are a few scattered sprinkles in various shades of brown^[3] and pink, these sprinkles and blotches concentrated at the top^[4] or form a sort of wreath at the larger end.^[3] The egg is not very glossy.^[4] It is 18 by 14mm in size.^[3][4] The shell is very thin.^[4]

Similar species

Baird compared and found it most similar to Setophaga coronata, finding it best distinguishable by having a nearly uniformly yellow belly, no conspicuous yellow rump or crown, less black in the feathers of the crown, and a considerably larger and stouter bill and feet.^[8] Henninger mentions he finds it to have a certain resemblance to S. magnolia.^[18] In The Bahamas it may be misidentified with S. dominica flavescens.^[17]

Hybrids

In late October 1997 a large hybrid Setophaga warbler was netted in the low elevation dry scrublands of the southernmost Dominican Republic, which based on morphology (plumage colour and anatomical measurements of size) and geography was most likely a hybrid between S. kirtlandii and S. fusca.^[14]

Distribution

It was originally only known from Kirtland's home state of Ohio.^[8] In the mid 20th century the breeding range of Kirtland's warbler was reduced to a very limited area in the north of the Lower Peninsula of Michigan. In recent years, breeding pairs have been found in the Upper Peninsula of Michigan, Wisconsin, and southern Ontario due to the expanding population.^[5] The birds winter in Cuba, The Bahamas and the nearby Turks and Caicos Islands, where they are found on all islands investigated.^[17] A number also overwinter on Hispaniola, in the Dominican Republic.^[7][14][19] Overwintering birds have been collected and sighted a number of times in Florida.^[20] It has been recorded as a rare accidental on Bermuda and Jamaica,^[11] and there is an uncorroborated report from coastal Mexico.^[20][21] It has also been observed in the summer in Québec, although it is not known to breed there.^[22]

Kirtland's warbler found in northwest Ohio on May 14, 2010, on the shores of Lake Erie where migrant warblers occasionally appear in spring, perhaps before crossing into Ontario.

Individuals first migrate from The Bahamas west to Florida and South Carolina in the second half of April to early May, and from there move further northwest and westwards until they reach the Mississippi River, which they then follow upstream to the mouth of the Ohio River during May. They reach their breeding grounds early in June,^[23] and then leave their breeding range between August and October.^[17]

Ecology

The Kirtland's warbler's summer breeding habitat is in northern Michigan. Breeding habitat is where a bird lays its eggs and raises its babies. The Kirtland's warbler only builds its nests on the ground in young jack pine forests found in Michigan and sometimes Wisconsin.

Habitat

In their winter habitat, they have been found primarily in low "coppice" habitat,^[17][24][25] especially areas which have been cleared for slash-and-burn agriculture but have regrown after abandonment (98% of all records), with a preference for dense shrubbery with small openings here and there, no canopy and low ground cover. It has otherwise been found in all habitats on the islands, including, albeit uncommonly, suburban gardens and Bahamian pineyards, with the exception of high coppice which has never been clear cut -it has never been seen here. With rare exceptions this bird is almost always sighted from the ground to 3m high (98%).^[17]

For breeding habitat it requires large areas of young jack pine (Pinus banksiana) on sandy soil. Kirtland's warblers occur in greatest numbers in large areas that have been clear cut or where a large wildfire has occurred.^[13][26] For breeding they require stands of young (6 to 20 year old, 2–4 m high) jack pine trees.^[17] Other common plants in this habitat are blueberry (Vaccinium angustifolium), sweet fern (Comptonia peregrina), Canada mayflower (Maianthemum canadense) and various grasses. Although it was initially believed to exclusively require jack pine stands, more recent research has found that the bird will also breed in some places in young stands of red pine (Pinus resinosa) of 10 to 15 years old.^[22] When the pine stands grow so tall so as to lose their lowest branches near the forest floor, the environment no longer provides sufficient cover.^[13] Such stands are ideally densely stocked with young pines, but also contain small occasional patches of open areas or with sparse tree cover.^[22]

This Lower Peninsula jack pine stand was slightly too young in 2002, but by 2008 made good breeding habitat. By 2015–2020, the mature trees would form a forest nearly 20m high, rendering it unsuitable for Kirtland's warbler breeding.

Controversy

The status of the overwintering habitat has been contentious, with researchers disagreeing. Mayfield (1992, 1996) first stated that the bird inhabits the shrub layer. Lee et al. (1997) also believed that the warbler inhabits shrubs, but they concluded that the species is entirely dependent on pineyards, stating that before the advent of deforestation of the high coppice after the colonisation of The Bahamas by pre-colonial Lucayan peoples, the bird must have been restricted to the northwestern islands which harbour these pineyards and absent from central, eastern and southern islands such as Eleuthera. Sykes and Clench (1998), basing their analysis on 96 unambiguous records of both collected specimens and observations on thirteen different islands, as well as almost 451 observations over three months of the same two banded individuals on Eleuthera, refuted the claim, finding that by far most records were from regrown coppice after abandonment of agricultural fields.^[17] Like Mayfield, they state many of the earlier records used by Lee et al. were tainted by misidentification with S. dominica flavescens, a similar-looking subspecies that was not adequately described or illustrated at the time of the recordings.^[7][17] A few months later, Haney et al. (1998) published a repudiation of Sykes and Clench based on 101 warbler records, wherein they claimed the warblers do not prefer scrub coppice and reiterated their earlier assertion that the primary habitat of the birds was pineyards. They went even further in concluding that the world population of the warbler was not limited by the situation in their breeding range in Michigan, but that historic fluctuations in their population were instead being determined by the status of the pineyards in Bahamas.^[7] A detailed study by Wunderle et al. (2010) using a much larger sample size of new data from 153 capture sites and 499 observations, and investigations of the diet, found that Sykes and Clench had been correct, and there was no validity to the assertions of Lee, Walsh-McGehee and Haney.^[24] Jones et al. (2013), researching the warbler on an island where pineyards had never grown, hypothesized that a sampling bias for birds in pineyards had skewed the results of the research presented by Haney et al.^[25] Despite the evidence, Birdlife International, which performs the IUCN Red List assessments, has consistently shown preference for the Haney et al. interpretation, stating that the conclusion that "changes in population have occurred contemporaneously with the degradation and recovery of the north Bahamas pine ecosystem" is more compelling than that the recovery efforts in Michigan were having effects on the population size.^[1]

Haney et al. stated that another reason that this warbler was most likely restricted to the pineyards habitat was because there was no low coppice habitat available until the arrival of the first human colonists on the islands, the Lucayans some 1,000 years ago, due to there being no mechanism that could destroy the natural high coppice of the islands.^[7] However, in 2007, Wunderle et al. pointed out that hurricanes might produce such young successional habitat, albeit with no empirical evidence; they theorized that perhaps this warbler species had specifically evolved to take advantage of such weather phenomena.^[27]

Behaviour

Yearlings and first-time breeders explore to find new breeding grounds,^[5][22] but ringed males have been observed to loyally return to the same nesting locality years after year; a male first ringed at CFB Petawawa in Ontario in 2006 returned for six consecutive years. This individual is estimated to have reached the age of nine, but in general the species are thought to have much shorter lifespans; males usually become four years old, and females are thought to only survive for 2.5 years on average.^[28]

One study found that 85% of the singing males are able to attract mates.^[7]

A warbler occupies a breeding territory of 2.7 to 3.4ha depending on location, but a larger wintering territory of 6.9 to 8.3ha depending on the island.^[17] They construct their nests on the ground, well concealed by lowest living branches of the jack pines and other vegetation.^[13][26] The nest is usually at the base of a tree, next to a down log or other structure. Eggs are laid in May to June.^[1]

Diet

It depends heavily during overwintering on the berries of Lantana involucrata, which is a very common successional shrub a few years after agriculture has been abandoned in a particular field.^[17] It is also said to eat the berries of Erithalis fruticosa^[24][25] and Chiococca alba.^[24] Of 331 observations of two warblers on Eleuthera in 1986, 76% were of foraging on Lantana, 8% were in Tournefortia volubilis, 4% in snowberry, 3.5% in Acacia rigens, 3.3% in Erithalis, 1.8% in Zanthoxylum fagara, and 1% Casuarina equisetifolia. Plants they were found foraging in at less than 1% were Sideroxylon salicifolium, Pithecellobium keyense, Tabebuia bahamensis and Scleria lithosperma.^[17] In its summering range this species feeds on blueberries and on insects such as spittlebugs, aphids and ants.^[13]

Interactions with other species

Jack pine is a species of pine with a distribution that spans almost across North America.^[26] Its cones open only after trees have been cleared away by forest fires or, after logging, in the summer sun. The ice age climate was somewhat drier overall and almost all of its present-day range was covered by solid ice as late as 10,000 to 15,000 years ago.^[29] Pollen analysis shows that the jack pine was almost non-existent between the Appalachian Mountains and the Great Plains during this period, with the possible exception of tiny isolated relict populations, which presents a mystery as to where the Kirtland's warbler survived during this period. Mayfield suggests that the species was restricted during this age to the southeastern Atlantic coast, which might explain its modern overwintering range in the Bahamas as opposed to Mexico, as well as why it appears to be closer related to Caribbean warbler species. The jack pine and the warbler likely colonized the Midwest around 10,000 years ago.^[26]

Without human intervention, the warblers are severely impacted by nest parasitism by the brown-headed cowbird. Blue jays prey on the nests and are a nuisance species because individual jays repeatedly allow themselves to get caught in the same traps used to exterminate the cowbirds of the nesting region.^[30]

Conservation

The Kirtland's Warbler Conservation Team is an integral part of post-delisting monitoring efforts and provides an important forum for sharing information, coordinating management efforts and ensuring that effective adaptive management occurs.

Decline

As global climate changed after the ice age through the last 10 millennia or so, jack pine, and consequently also Kirtland's warbler, shifted their habitat north.^[26] The cold-hardy jack pine now grows as far as north as the Northwest Territories.^[31]

The Kirtland's warbler has historically always been rare, with the species first recorded quite late for a bird from the eastern USA between the 1840s to 1851, only four or five birds seen in the first two decades after, and the breeding grounds and first nest not recorded in 1903 in Michigan.^{[5][8][6][7][10]}

It is still unclear to scientists how a species with such narrow habitat requirements was able to survive to modern times. One theory is that during the ice ages, which lasted much longer than interglacials, Kirtland's warbler had a more stable distribution and habitat; i.e. the species exists as a glacial relict during geologically brief periods of warming global temperatures. It is quite possible that colonization by Europeans actually temporarily boosted populations of the bird. Most of the Lower Peninsula of Michigan was once covered in vast tracts of old growth white pine (Pinus strobus), the final stage of succession in the woodlands of that region, but these were all harvested by the early 19th century for construction in the growing cities and towns around the Great Lakes and along the East Coast. This created the conditions for the extensive woodlots of jack pine, a pioneer species, found today.^[26][32]

In 1871, fed by dry conditions, high winds and piles of logging slash, a massive forest fire swept through lower Michigan, with another largefire in The Thumb of the Lower Peninsula, and a further huge forest fire on the Wisconsin-Michigan border and yet another around Windsor, Ontario. In 1881 another massive conflagration burned down the forests in The Thumb, which eliminated the last of the original white pine woodlands of Michigan. This period coincides with the era where most Kirtland's warbler specimens were collected, reflecting a possible peak in population size. However ornithologists were then unaware where it bred, and almost all these birds were taken in The Bahamas and Turks and Caicos or along the migration route. While no warblers were seen or killed in The Bahamas by the collector Henry Bryantin in the 1850s and 1860s (despite his extensive searches),^[32] many dozens of warblers were recorded on almost all of the islands by the 1880s and 1890s. Charles Johnson Maynard collected 24 from New Providence during one two and a half month excursion in 1884.^[7][32] Maynard was a prolific collector, securing in this and subsequent years another ten on the same island almost a dozen on Eleuthera, and a further two on Cat Island, but many other collectors were able to obtain quite a number of specimens in The Bahamas during these decades.^[7]

In July 1903, the taxidermist Norman Asa Wood was presented with a specimen by a student at the University of Michigan, and promptly travelled to the area it was killed, where he found the first nest ever recorded for the species near the banks of the Au Sable River. He also found a second nest; both nests had chicks and one held a single unhatched egg. Wood killed all the birds he could (eight managed to escape his gun), and secured the nests and egg. He tried to rear some of the chicks, but these soon died. Including chicks, he returned to the city with fifteen specimens, the biggest collection of the species at the time in the USA. It was thus one of the last bird species of North America to have its nesting habits discovered.^[3][23] The following year Edward Arnold travelled to a nearby locality in June and found the third nest ever, with four eggs. He was able to capture both the male and female on the nest simply with his hands.^[4] Including these, 25 birds had been taken in Michigan by 1904, and another eight recorded, which made it clear that Michigan was the main stronghold of the breeding range of this warbler.^[3][4]

Considering the vernacular name of this bird was "jack pine bird" in Michigan,^[3][4] Wood was certainly was not the first to discover that this species is specifically resident in jack pines, but in 1904 he was the first to publish these findings in a scientific journal. Woods also noted that, even in its breeding haunts, the bird was quite rare, and was not present in all areas of jack pine.^[3] This same year the migration route was first detailed in a paper by Charles C. Adams. Adams used dates of records of this bird in different states to show it migrated according to a very tight schedule, but used quite a broad route north spanning from the Mississippi River to South Carolina. He thought this might indicate that there were more breeding grounds to the west and east than those in Michigan which Woods had publicised.^[23] The records Adams was using are from the 1880s and 1890s and birds were shot as far west as Missouri and Minnesota, areas where the species has not been seen since.^[32]

In the 1920s, a recognised expert on this species was a Chicago teenager named Nathan F. Leopold (most well known for being one half of the crime pair Leopold and Loeb) who, in his scientific journal articles, published a number of important discoveries. One was that the age of the jack pines in a stand is the most pertinent determinant in the suitability of a particular terrain as a breeding habitat for the species, and another discovery was that the population was subject to a deleterious brood parasitism by the brown-headed cowbird.^[33][34]

Kirtland's warbler is highly susceptible to nest parasitism by this cowbird.^[30] Brown-headed cowbirds feed mostly on seeds from grasses and weeds, with some crop grains. Insects such as grasshoppers and beetles, often caught as cows and horses stir them into movement, make up about a quarter of a cowbird's diet. Development and fragmentation of forests in the eastern United States have allowed brown-headed cowbirds to greatly expand their range eastward.^[35] One study from 1931 to 1971 found 59% of the warbler nests parasitised in comparison to 5% of the nests in the study area of all other bird species combined, another study found 48% from 1903 to 1949; another found 86% rate of parasitism; and a last study found 69% of the warbler nests afflicted from 1957 to 1971. In 1971 the third decennial census counted 201 singing males, whereas the 1961 census had found 501 breeding pairs, showing a 60% decrease in population over the 1960s.^[30]

The first census of the species was performed in 1951, organised in part by a young Harold F. Mayfield, who would eventually spend the rest of life researching this species. 432 males were counted, half of these in just two areas where fires had raged in the 1930s. The second of what was supposed to be a decennial census program in 1961 showed an increase in population, with 502 males counted; many of these were still found at the sites of the two 1930s fires, a quarter was now resident at the site of a large fire from 1946.^[32]

The population reached a low of 167 singing males in 1974,^[22][30] and in 1994 only 18 square kilometres (6.9 sq mi) of suitable breeding habitat was available.^[1][36]

Recovery

It was listed as endangered in the US in 1967.^[37] In 1971 a recovery plan was developed. The plan entailed the management of state and federal land through clear cutting, controlled burning and planting jack pine to expand suitable nesting habitat for Kirtland's warbler, as well as having the government acquire more land for this purpose. The other components were to limit public access land during nesting season, to conduct annual censuses of the warbler population, and lastly to intensively control the cowbird population.^[30]

A 1966 study found that shooting and trapping the cowbirds could reduce parasitism from 65% to 21%, and in 1972 cowbird control efforts commenced. The cowbird traps were 4 by 4 ft. and 6 ft. high with a recessed entrance hole at the top, and worked using sunflower seed bait, tape recorders playing birdsongs and decoy cowbirds which attracted more cowbirds. Cowbirds are asphyxiated in plastic bags using car exhaust fumes. Once a day during breeding season, or when the traps had collected 30 to 40 birds, the traps were serviced to destroy cowbirds. Other trapped bird species were banded and released, and some twelve cowbirds were left in the trap as decoys. Less cowbirds are caught as the season progresses, and radio-tracked cowbirds indicate that females are sedentary during the season. In the first year, 1972, 2,200 cowbirds were eliminated using a single trap, and only 6% of the warbler nests in the region were parasitised compared to 69% previously. Average clutch size in the region almost doubled. In 1973 the program was expanded to four traps, which caught 3,300 cowbirds and resulted in no parasitism that year. That same year 216 singing male warblers were recorded an increase of 9.2% from the 200 males recorded in 1972, and the first increase recorded ever. Thus the control program was considered a success, and the following year 22 cowbird traps were deployed, removing over 4,000 cowbirds across the region. Although only 167 singing male warblers were recorded in 1974, nevertheless the large number of fledglings meant the traps were effective.^[30] As of 2016, the cowbird traps still capture 4,000 cowbirds a season.^[38][39] Effective blue jay management involves transporting a few hundred jays a year dozens of miles away to be released.^[30]

Today the habitat of Kirtland's warbler is no longer being preserved by prescribed burns as these have proved too difficult to control (a forest service employee named James Swiderski was immolated during one of these burns in 1980),^[5][40] and the species is entirely dependent on staggered harvests by the timber industry for its survival. Some 76,000 hectares are reserved for this purpose on the Lower Peninsula of Michigan, of which some 15,000 are maintained as young jack pine breeding habitat for the bird.^[5] The Michigan Department of Natural Resources, the U.S. Fish and Wildlife Service and the U.S. Forest Service coordinate the clear cutting of tracts of 50 year old jack pines on 23 Kirtland's warbler management units. These managed units total 220,000 acres (89,000 ha). After cutting new trees are planted in a specified pattern to mimic the natural habitat the warbler needs, with clearings and dense thickets.^[39]

In 2004 Kirtland's warbler had been observed in Ontario^[22] and the Upper Peninsula of Michigan, and rarely recorded in northwest Ohio, where the numbers of recorded birds are increasing.^[41] Beginning in 2005 a small number have been observed in Wisconsin. In 2007 three Kirtland's warbler nests were discovered in central Wisconsin^[42] and one at CFB Petawawa in Ontario,^[43] providing a sign that they are recovering and expanding their range once again. The Wisconsin population continues to grow, with 53 individuals and twenty nests recorded in 2017.^[44]

In the IUCN Red List the Kirtland's warbler was classified as vulnerable to extinction since 1994, but was listed as near threatened in 2005 due to its recovery.^[39] Although there seemed to be no more than 5,000 Kirtland's warblers as of late 2007,^[45] four years earlier they had numbered just 2500–3000. Since the recovery plan began in the 1970s, the numbers of Kirtland's warbler have steadily risen, with an estimated population of 5,000 in 2016.^[39] A world total of 2,365 singing males were reported in the 2015 census.^[22] By 2018 there were an estimated 2,300 pairs and the population had continued to grow over the previous sixteen years according to the U.S. Fish and Wildlife Service Midwest Region.^[39] In 2019 the population has been above the recovery goal of 1,000 pairs for seventeen years.^[37]

The birds depend on The Bahamas and adjacent territories during winter; in 1998 their winter habitat was judged to be extremely widespread and it was calculated that there is enough area and habitat in the Bahamas to house a population of roughly more than 500,000 birds. The most destructive threat in the winter range are thought to be house cats, at least on some islands.^[17]

If Haney et al. are correct in arguing that the species does not overwinter in scrub coppice habitats in The Bahamas, but instead in pineyards, and the abundance of this species is in fact limited by changes in this pineyard habitat, the conservation efforts in Michigan may be insufficient for species recovery.^[1] Some Michigan locals have questioned the cost and point of the program.^[40] Habitat and cowbird management cost $1 million per year as of 2003. In the 1990s this was garnered from a carbon sequestration fund, but that source of financing has been terminated.^[1] Management costs were estimated at $1.5 to 2 million per year in 2008,^[38] however, the payments by timber companies for the sale of jack pine for manufacturing paper and wood pulp offsets some costs,^[37] and the species brings bird-watching tourists to the region which is an economic boon to local businesses.^[37][38] Survival of this species will require management that will need to continue in perpetuity. An endowment fund to ensure a permanent funding source for the species has been discussed as an option.^[38]

There is a Kirtland's warbler festival in Roscommon, Michigan, which is sponsored in part by Kirtland Community College (which is named in honour of the bird). The festival is held annually during the first full weekend of June.^[46][47][48]

Canada

Until 2007 Kirtland's warblers had never been known to have bred in Canada,^[5] with the exception of one ambiguous possible record from near Midhurst, Ontario in 1945.^[22][49] The first bird was collected in the country in 1900 when a specimen was secured on Toronto Island.^[49] The bird was then seen in the country in 1916 at the army base of CFB Petawawa by a military dentist, Paul Harrington; the same dentist made the third sighting of Canada at the same location in 1939,^[5][49] and in the next 65 years a bit more than two dozen sightings of the bird were made in the country, although only a few are verified.^[49] In 1979 it was declared an endangered species of Canada on the basis that it may have once bred in Ontario. In 2006 suddenly three birds were recorded at Petawawa, and the subsequent year the first ever nest was recorded at the same locality.^[5][43] The habitat at this location appears to have been maintained due to fires stemming from military training exercises.^[22] After 2007 the bird has bred almost every year at Petawawa, with the birds here fledged 27 young by 2014,^[28] and it has been reported at additional locations in central Ontario.^[22]

The government of Ontario published a recovery strategy for the Kirtland's warbler in 2016.^[22] A new mixed red and jack pine stand was planted at a location in Simcoe County in 2018 in the hopes of attracting the warbler,^[50] of which a sighting in the area had earlier been reported.^[22] Red pine was interspersed with the jack pine because the latter is relatively worthless as lumber, and it was hoped this configuration would make the project more economically sustainable.^[50]

Delisting

Prior to being delisted from the United States Fish and Wildlife Service list of endangered mammals and birds in 2019,^[51][52] the Kirtland's warbler had been listed as "endangered" under the Endangered Species Act of 1973.^[53] Since delisting, continued monitoring is being used to ensure that the species remains secure.^[51]

Protected areas

It has been regularly recorded in the following protected areas:

• Abaco National Park, Abaco, The Bahamas.^[7]
• Algonquin Provincial Park, Ontario, Canada.^[11]
• Hartwick Pines State Park, Michigan, USA.^[48]
• Huron-Manistee National Forests, Michigan, USA.^[48]
• Lucayan National Park, Grand Bahama, The Bahamas.^[7]
• Point Pelee National Park, Essex County, Ontario, Canada.^[13]
• Rand Nature Centre (as Pinelands Wilderness Sanctuary), Grand Bahama, The Bahamas.^[7]
• Tawas Point State Park, Michigan, USA.^[48]

See also

• Mutualism (biology)
• Kirtlands Warbler Wildlife Management Area

References

La Kirtlanda parulio, Dendroica kirtlandii, estas malgranda paserina birdo de la familio de Paruliedoj de Ameriko kaj granda genro de Dendroica. Ĝi estas interesa specio kiu dependas nune de la homa agado pro ties survivado kaj evito de formorto.

Ĝeneralaĵoj

Tiu nearktisa birdo ricevas sian nomon laŭ Jared P. Kirtland, doktoro kaj amatora naturalisto de Ohio. La specio estis preskaŭ formortinta antaŭ 50 jaroj, sed nun estas survoje al rekuperado. Ĝi postulas grandajn areojn de densa arbetaro de Banks-pino por sia reprodukta biotopo. Tiu vivejo estis historie kreata de naturaj incendioj, sed nune ĝi estas ĉefe kreata per rikolto kaj plantado de semoj de tiuj Banks-pinoj^[1].

ino

Ekde mezo de la 19a jarcento almenaŭ ĝi iĝis endemia specio kun tre limigita teritorio. Preskaŭ la tuta populacio pasas printempon kaj someron en nordoriento de la Malsupra Duoninsulo de Miĉigano kaj vintrumas en Bahamoj.

Aspekto

Tiuj malgrandaj birdoj (15 cm longaj) estas raraj kaj malfacile videblaj. Ili havas bluecgrizajn suprajn korpopartojn kun malhela strieco en dorso kaj flavaj subaj partoj kun striecaj flankoj foje ĝis la brusto. Ili havas fajnajn flugilstriojn, malhelajn krurojn kaj blankajn duonigitajn okulringojn rimarkindajn ĉe malhela vizaĝo. La beko estas nigreca, fajna kaj pintakra. Inoj kaj junuloj estas pli brunaj en dorso, dum maskloj estas pli grizaj kaj havas nigrajn bridojn, dum inoj kaj junuloj havas ilin grizajn. Kiel ĉe la Palmoparulio kaj la Preria parulio, ili ofte skuas siajn vostojn, sed ne eblas konfuzo, ĉar tiuj specioj havas flavajn pugojn kaj vizaĝojn kaj ne havas la rompitan okulringon. La subvosto estas blanka.

Kutimaro

Ĝi estas timida, malgranda, aktiva insektomanĝulo. Kirtlandaj parulioj manĝas en la subaj partoj de arboj, foje ŝvebante aŭ serĉe surgrunde. Tiuj birdoj manĝas insektojn (raŭpoj, papilioj, tineoj, muŝoj kaj akridoj), pinsemojn kaj kelkajn berojn, kiel tiuj de neĝobero, kaj manĝas ankaŭ fruktojn vintre. Ties kanto estas tre laŭta ĉip-ĉip-ĉip-too-too-ŭiit-ŭiit ofte kantata el pinto de stumpo de mortinta arbo aŭ tufo de Norda pinkverko (Quercus ellipsoidalis). Ili banas sin en roso.

La masklo atingas la unua la reproduktan teritorion por sekurigi ĝin kaj je la alveno de la ino plenumas pariĝadajn ceremoniojn per descenda flugo super la ino. Por reproduktado ili postulas arojn de junaj (4 al 20jaraĝaj, 2-4 metrojn alte) arbetoj de Banks-pino. Ili nestumas surgrunde. Ties nesto estas tasforma konstruo kutime ĉebaze de arbo, ĉe malalta branĉo aŭ alia strukturo, farita el herbo aŭ aliaj plantofibroj kiel arboŝeleroj, kovrita el fajna herbo, pinpingloj, musko kaj haroj kaj estas bone kaŝita pere de karekso, herberoj, mirteloj aŭ alia grunda vegetaĵaro. Ambaŭ seksoj helpas por la nestokonstruado. La 4 al 6 ovoj estas blankaj al kremorozkolorecaj, markataj je bruna, ĉefe ĉe la larĝa pinto (18 mm). Nur la ino plenumas la kovadon kiu daŭras 14-16 tagojn (plej longa inter nordamerikaj paruliedoj), sed la masklo manĝigas la inon. Post eloviĝo la idoj estas nekapablaj kaj elnestiĝo okazas post 10-13 tagoj sed la idoj restas proksime kaj estas manĝigataj de ambaŭ gepatroj dum pli da 2 semajnoj.

Teritorio kaj ekologio

Ties reprodukta teritorio estas en tre limigita areo de la nordo de la Malsupra Duoninsulo de Miĉigano. Ĵuse oni trovis reproduktantajn parojn ankaŭ en la Supra Duoninsulo de Miĉigano, Viskonsino kaj Ontario pro rapida etendo de populacio. Reprodukta biotopo estas tipe grandaj areoj de densa arbetaro de junaj Banks-pinoj (Pinus banksiana). Kirtlandaj parulioj loĝas en plej grandaj nombroj en grandaj areoj kiuj estis klarigataj aŭ kie granda natura incendio okazis^[1]. Tiuj birdoj lasas siajn reproduktajn biotopojn inter aŭgusto kaj oktobro kaj migras al Bahamoj kaj apudaj insuloj Turkoj kaj Kajkoj; ili revenas al Miĉigano por denova reproduktado en majo. En siaj vintraj vivejoj, ili troviĝas ĉefe en arbustaro, kie manĝas ĉe salvio Salvia verbenaca, ĉe Erithalis fruticosa kaj ĉe neĝobero ^[2].

Vivejo

Tiu arbaro de Banks-pino de la Malsupra Duoninsulo estis ankoraŭ tro juna en 2002, sed je 2008 estus taŭga reprodukta biotopo. Je 2015–2020, la maturaj arboj formus arbaron ĉirkaŭ 20 metrojn altan kaj la Kirtlanda parulio jam ne volus reproduktiĝi tie plu.

Ekologio de la Banks-pino

Banks-pinoj estas iom malgrandaj pinoj disvastigataj el kanadaj tundro kaj tajgo al la regiono de la Grandaj Lagoj kaj de la Atlantika Oceano; ili estas boreala specio, kiu vivas nur je preciza klimato^[3]. Ties strobiloj malfermiĝas nur post kiam la arboj estis forklarigataj fare de arbarincendioj aŭ pro lignoproduktado sub somera suno. La reprodukta strategio de tiu pino kongruas kun seka tajgo aŭ freŝa moderklimata habitato kio hegemoniis en nordaj glaciaj teritorioj, probable kun multe pli da incendioj ol nuntempe, dum la glaciepoko sekiĝis pli kaj pli^[4].

Malpliiĝo al preskaŭ formorto

Dum la klimato ŝanĝis el la glaciepoko dum la lastaj 10 jarmiloj aŭ iom simile, la Banks-pino, kaj sekve ankaŭ la Kirtlanda parulio, ŝanĝis siajn vivejojn norden. Ĉar la Kirtlanda parulio - kaj Paruliedoj ĝenerale – ne povas etendi al subarktaj klimatoj bone, plej parto de la arbaroj de Banks-pino restis tro norde por tiu specio. Krome la Grandaj Lagoj, kiuj formiĝis antaŭ la reeniro de la glaciepoko, estis baro por ties disvastigo. La Kirtlanda parulio troviĝis barita de la etendo de la akvoj, dum la malvarmema Banksia pino etendis sian teritorion tiom for kiom ĝis la Nordokcidentaj Teritorioj.

Dum la Eŭropa koloniigo de Ameriko progresis, multo de la arbaro de la regiono sude de la Grandaj Lagoj estis forhakita kaj neniam rearbarigita. La Kirtlanda parulio restis barita en la Norda Duoninsulo. Kvankam ĝi loĝis iam kie la Dro. Kirtland donis sian nomon, tio estas en la ŝtato de Ohio kaj li mortis en 1877, je la fino de la 19a jarcento certe la birdo jam ne reproduktiĝis tie plu en 1906^[5]. La Kirtlanda parulio reproduktiĝis en Ontario sed jam ne plu el la 1940-aj jaroj. Meze de la 20a jarcento ties nombroj malpliiĝis ĝis preskaŭ formorto. La populacio de Kirtlanda parulio estis nur de ĉirkaŭ malpli da 500 individuoj ĉirkaŭ la 1970-aj jaroj, kaj en 1994 nur 18 km² de taŭga reprodukta biotopo estis disponebla.^[6].

Rekuperado

Nuntempe la vivejo de tiu birdo estas zorgata pere de kontrolataj incendioj kaj rikoltadoj de ligno en ties limigita reprodukta teritorio. Ekde kiam tia administrado de vivejo komencis en la 1970-aj jaroj, la nombroj de la birdo rapide kreskis, kvankam la specio estas ankoraŭ je danĝere malaltaj niveloj. Homoj intervenas ankaŭ por protekti tiun birdospecion kontraŭ nestoparazitado fare de la Brunkapa molotro forigante tiun specion de la teritorio, kiun ĝi atingis nur antaŭ unu jarcento malpermesante tiele la disvolvigon de defensa strategio fare de la Kirtlanda parulio. Estis nur ĉirkaŭ 170 reproduktantaj maskloj restantaj en 1987. Ĉirkaŭ 1995 estis jam 765 reproduktantaj maskloj en Miĉigano, sed tiu nombro falis al 692 en 1996.

Ili estis ankoraŭ observataj en Ontario kaj la Supra Duoninsulo de Miĉigano, kaj kvankam ĝi estas ankoraŭ nur rare vidata en NOk Ohio (kie restis malmulte taŭga arbaro), la nombroj de vidataj birdoj pliiĝas^[7]. El 2005 malgranda nombro estas observata en Viskonsino. En 2007 tri nestoj de Kirtlanda parulio estis malkovrataj en centra Viskonsino^[8] kaj unu ĉe armebazo de Petawawa^[9].

La Kirtlanda parulio estas listata kiel "endanĝerita" ĉe la listo de Endangered Species Act de 1973.^[10] Kvankam ŝajne ne estas pli da 5,000 Kirtlandaj parulioj ĉirkaŭ 2007 ^[11], kvar jarojn antaŭe ili estis nur 2,500-3,000. En la "Ruĝa Listo de Minacataj Specioj" de IUCN la Kirtlanda parulio estas klasita kiel Vundebla al formorto ekde 1994, sed poste estis relistata al Preskaŭ Minacata en 2005 pro la enkuraĝiga rekupero. Ne klaras je kioma etendo la birdoj dependas de la karibaj pinoj dum vintro; nuntempe senarbarigo en vintrejoj povas eventuale iĝi pli gravan minacon al rekupero de la birdospecio ol la situacio en ties reprodukta teritorio.^[6]

La Michigan Department of Natural Resources ĵus faris optimismajn informojn pri la populacioj de Kirtlanda parulio.^[12]

Ĵusaj informoj indikas, ke la populacio kreskas, sed oni sugestas ankaŭ ke la Kirtlanda parulio povus plue dependi de la homa protektado kaj interveno porĉiame.^[13]

Estas Naturfestivalo pri Kirtlanda parulio, kiu estas subvenciita parte de Kirtland Community College (kiu ricevis sian nomon honore de la birdo kaj ties vivejo).^[14]

Notoj

Vidu ankaŭ

• Bahamaj pinaroj

Referencoj

• BirdLife International (BLI) (2005). Dendroica kirtlandii. Internacia Ruĝa Listo de Endanĝeritaj Specioj, eldono de 2006. IUCN 2006. Elŝutita 11a Majo 2006. Preskaŭ Minacata
• CFB Petawawa (CFBP) (2007): Canada's Rarest Nesting Bird found at CFB Petawawa. Versio de 2007-Nov-01. Konsultita 2008-FEB-19.
• Henninger, W.F. (1906): A preliminary list of the birds of Seneca County, Ohio. Wilson Bulletin 18(2): 47-60. DjVu plena teksto PDF plena teksto
• Mayfield, Harold (1960): The Kirtland's Warbler. Cranbrook Institute of Science Bulletin 40.
• Ohio Ornithological Society (OOS) (2004): Annotated Ohio state checklist. Versio de Aprilo 2004. PDF plena teksto
• Peel, M.C.; Finlayson, B.L. & McMahon, T.A. (2007): Updated world map of the Köppen-Geiger climate classification. Hydrology and Earth System Sciences 11(5): 1633-1644. PDF plena teksto Suplemento
• Ray, Nicolas & Adams, Jonathan M. (2001): A GIS-based Vegetation Map of the World at the Last Glacial Maximum (25,000-15,000 BP). Internet Archaeology11. PDF plena teksto
• United States Fish and Wildlife Service (USFWS) (2007): Kirtland's Warbler 2007 Nesting Season Summary. Versio de 2007-DEC-10. Konsultita 2008-FEB-19.

La reinita de Kirtland (Setophaga kirtlandii),^[2]​ también conocida como chipe de Kirtland o ciguita kirtlandii,^[3]​ es una especie de ave paseriforme de la familia Parulidae encontrada en Norteamérica. El nombre de la especie conmemora a Jared P. Kirtland, un médico y naturalista aficionado de Ohio.

Descripción

Hembra

Es la especie más grande en su género, mide unos 14-15 cm de longitud y pesa entre 12 y 16 gramos.^[4]​ Tiene las partes superiores del cuerpo de color marrón azulado con rayas oscuras, y las partes inferiores de color amarillo con rayas en los flancos. Tiene barras delgadas en las alas, patas oscuras y el anillo ocular blanco. Las hembras y los juveniles tienen el dorso más marrón. Su canto es un sonoro chip-chip-chip-too-too-weet-weet cantado a menudo desde lo alto de un árbol.

Distribución y ecología

Su área de reproducción es una zona muy limitada en la península de Míchigan. En los últimos años se han encontrado parejas reproductoras en Wisconsin y en el sur de Ontario, probablemente debido al rápido crecimiento de la población. Abandonan su hábitat de cría entre agosto y octubre y migran a las Bahamas y Turcas y Caicos; regresan a Míchigan para reproducirse de nuevo en mayo.

Se alimentan de insectos y algunas bayas que encuentran en las partes más bajas de los árboles, también comen fruta en el invierno.

Referencias

Michigani säälik (Setophaga kirtlandii) on sääliklaste sugukonda kuuluv lind. Ta on Michigani osariigi endeem. Talvitub Bahamal ning Turksi ja Caicose saartel. Michigani säälik vajab pesitsemiseks laialdasi halli männi (Pinus banksiana) noorendikke.

Viited

Välislingid

• Birdlife'i veebileht

Setophaga kirtlandii Setophaga generoko animalia da. Hegaztien barruko Parulidae familian sailkatua dago.

Erreferentziak

• World Bird Names

Ikus, gainera

• Setophaga
• Parulidae

Kulokerttuli eli vanhalta nimeltään kirtlandinkerttunen^[2] (Setophaga kirtlandii) on Yhdysvaltain kotoperäinen varpuslintu. Sen pesimisalueet sijaitsevat Michiganin osavaltion pohjoisosassa. Se on muuttolintu, joka talvehtii Bahamalla sekä Turks- ja Caicossaarilla. Spencer Fullerton Baird kuvaili lajin holotyypin Clevelandin läheltä Ohiosta 1852.^[3]

Lähteet

Setophaga kirtlandii

La Paruline de Kirtland (Setophaga kirtlandii, anciennement Dendroica kirtlandii) est une espèce de passereaux de la famille des Parulidae.

Répartition

• zone de nidification
• zone d'hivernage

Kirtlands zanger (Setophaga kirtlandi synoniem:Dendroica kirtlandii) is een zangvogel uit de familie Parulidae (Amerikaanse zangers).

Kenmerken

Beide geslachten hebben blauwgrijze bovendelen en een witte oogring. De lichaamslengte bedraagt 15 cm.

Verspreiding en leefgebied

Deze soort is endemisch in de Noord-Amerikaanse staat Michigan en overwintert op de Bahama's.

• David Burnie (2001) - Animals, Dorling Kindersley Limited, London. ISBN 90-18-01564-4

Kirtlandskogssångare^[2] (Setophaga kirtlandii) är en fågel i familjen skogssångare inom ordningen tättingar.^[3]

Utbredning

Kirtlandskogssångaren häckar i ett väldigt begränsat område med banksianatall i Michigan, USA, och övervintrar i Bahamas.^[3]

Status

IUCN kategoriserar arten som nära hotad.^[1]

Namn

Fågelns svenska och vetenskapliga artnamn hedrar den amerikanska naturforskaren Jared Potter Kirtland (1793-1877).^[4]

Referenser

1. ^ [a b] Birdlife International 2016 Setophaga kirtlandii Från: IUCN 2016. IUCN Red List of Threatened Species. Version 2016.3 www.iucnredlist.org. Läst 2016-12-11.
2. ^ Sveriges ornitologiska förening (2017) Officiella listan över svenska namn på världens fågelarter, läst 2017-08-14
3. ^ [a b] Clements, J. F., T. S. Schulenberg, M. J. Iliff, D. Roberson, T. A. Fredericks, B. L. Sullivan, and C. L. Wood (2017) The eBird/Clements checklist of birds of the world: Version 2017 http://www.birds.cornell.edu/clementschecklist/download, läst 2017-08-11
4. ^ Jobling, J. A. (2016). Key to Scientific Names in Ornithology. Ur del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (red.) (2016). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. Hämtad från www.hbw.com.

Externa länkar

• Wikispecies har information om Setophaga kirtlandii.
  Artförteckning

Setophaga kirtlandii là một loài chim trong họ Parulidae.^[1]

Chú thích

Tham khảo

• Dữ liệu liên quan tới Setophaga kirtlandii tại Wikispecies

Bài viết Bộ Sẻ này vẫn còn sơ khai. Bạn có thể giúp Wikipedia bằng cách mở rộng nội dung để bài được hoàn chỉnh hơn.

• x
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黑紋背林鶯（學名Dendroica kirtlandii）是一種細小的鳴禽。50年前它們接近滅絕，但現已逐步恢復。它們需要大片的北美短葉松林來繁殖。這種棲息地起初是由山火所造成，但現時則是透過砍伐及重新種植北美短葉松而來。^[2]自19世紀中葉它們的分佈地就有所限制，差不多整個群落都會留在密西根下半島東北部及在巴哈馬過冬。

黑紋背林鶯的上身呈藍褐色，背上有黑色斑紋，下身呈黃色，兩側有斑紋。雙翼上有幼紋，腳呈深色，眼睛周圍有白圈。雌鳥及幼鳥的背部較為褐色。它們像棕櫚林鶯及高草原林鶯般會上下擺動尾巴。

分佈及生態

黑紋背林鶯分佈在密西根下半島北部非常有限的區域。它們後來延伸至安大略省南部。近年它們會在密西根上半島、威斯康辛州及安十略省出沒，可能是因急速擴張的群落。它們需要很大片的北美短葉松來進行繁殖，面積多於160英畝。在皆伐或曾發生山火的地方會出現大量的黑紋背林鶯。^[2]到了8月至10月間，它們會離開繁殖地及遷徙到巴哈馬和鄰近的特克斯和凱科斯群島。到了5月，它們會回到密西根州繁殖。過冬的時候，它們主要會棲息在叢林中，吃藥用鼠尾草及雪果。^[3]

黑紋背林鶯會在樹的底部覓食，有時則會走到地上。它們主要吃昆蟲及一些草莓，冬天也會吃果實。它們需要北美短葉松來繁殖。它們會在地上或樹的基部築巢，並會以草、藍莓及其他地上植物來遮蔽。

保育狀況

衰落

自冰河時期後，全球的氣候也在轉變，北美短葉松及黑紋背林鶯也逐步向北遷移。由於黑紋背林鶯不能在亞北極氣候生存，故北美短葉松的分佈對它們來說算是較疏遠。再者，五大湖也成為了它們擴張的阻礙。

當美洲殖民時期，五大湖南部大部份的森林都被砍伐，黑紋背林鶯就被困在北方的半島中。到了19世紀末，它們在俄亥俄州的棲息地也被清除，於1906年它們已沒有在當地繁殖。^[4]自1940年代後，它們也沒有在安大略省繁殖。直至20世紀中葉，其數量下降至接近滅絕。於1970年代，它們的數量達到最低點，只餘下少於500隻；於1994年，它們只分佈在18平方公里大的地方。^[1]

復原

黑紋背林鶯的棲息地現已受到保護。自1970年代的保護後，它們的數量平穩上升，但仍處於危險的水平。另外，保育工作還包括對抗寄生的棕頭牛鸝。

黑紋背林鶯現已再次在安大略省及密西根上半島出沒，但卻很少在俄亥俄州西北部出現。^[5]於2005年初，在威斯康辛州也有少量的出沒。於2007年，三隻黑紋背林鶯在威斯康辛州中部出現。^[6][7]

黑紋背林鶯於1973年被列為瀕危。^[8]國際自然保護聯盟於1994年將之列為易危，但於2005年下調至近危。現時未知黑紋背林鶯對巴哈馬松樹的倚賴程度，但伐林等問題始終是它們的最大威脅。^[1]近年的報告都指黑紋背林鶯的數量正在上升，但也指出它們對人類保護的倚賴。^[9]

參考

外部連結

• All About Birds
• Michigan Department of Natural Resources
• The Nature Conservancy Songbirds

カートランドアメリカムシクイ（Dendroica kirtlandii）は、スズメ目アメリカムシクイ科に分類される鳥類。

分布[編集]

アメリカ合衆国、イギリス（タークス・カイコス諸島）^[1][2]

夏季にウィスコンシン州やミシガン州で繁殖し、冬季になるとタークス・カイコス諸島へ南下し越冬する^[1][2]。

形態[編集]

全長14-15センチメートル^[1][2]。翼開張20センチメートル^[2]。背に黒い縦縞が入る^[1][2]。眼の上下に三日月状の白い斑紋が入る^[1][2]。

嘴は黒い^[1]。

卵の殻は白く褐色の斑点が入る^[2]。

オスの成鳥は上面の羽衣が青灰色で、頭部に黒い縦縞が入り眼先も黒い^[1][2]。下面の羽衣は黄色で、体側面に黒い斑紋が入る^[1][2]。メスの成鳥は頭部に縦縞が入らず、眼先も黒くない^[1][2]。また頸部側面や胸部に黒い斑紋が入る^[2]。

生態[編集]

繁殖地では樹高2-4メートルのバンクスマツからなる低木林、越冬地ではカリビアマツからなる森林や広葉樹林、低木林に生息する^[1][2]。越冬地では他種と混群を形成する。

食性は雑食で、昆虫、果実、樹液を食べる^[2]。地表や樹上で採食を行う^[1]。

繁殖形態は卵生。植物で隠れた木の根もとの窪みにや草、枯れ葉、コケ、獣毛などを組み合わせたお椀状の巣を作り^[1]、1回に3-6個（主に4個）の卵を産む^[2]。メスのみが抱卵し、抱卵期間は13-15日^[2]。コウウチョウに托卵されることもある^[1][2]。雛は孵化してから9日で巣立つ^[2]。

人間との関係[編集]

バンクスマツの低木林は山火事のあとにできるため森林管理による山火事の減少、コウウチョウによる托卵の増加などにより生息数は減少した^[1][2]。繁殖地の森林で人為的に山火事の後の状況を再現したり、コウウチョウの駆除、環境教育やエコツーリズムといった啓蒙活動などの保護対策が進められている^[2]。一方で越冬地での生息地の破壊も懸念されている^[2]。繁殖地での1987年における囀るオスの生息数は167羽、1994年における囀るオスの生息数は633羽、1999年における囀るオスの生息数は903羽と推定されている^[1][2]。

画像[編集]

• メス

参考文献[編集]

関連項目[編集]

外部リンク[編集]

1. ^ The IUCN Red List of Threatened Species
   • BirdLife International 2008. Dendroica kirtlandii. In: IUCN 2010. IUCN Red List of Threatened Species. Version 2010.2.