Brown thrashers belong to the mimic thrush family, Mimidae. They are among the most vocal birds and often mimic other species. Other birds in this group include northern mockingbirds (Mimus polyglottos) and gray catbirds (Dumetella carolinensis).
The best time to observe these birds is in April, before nest sites are established. During this time males sing on high branches to attract mates.
Brown thrashers communicate mainly with vocalizations. They use mimicry extensively as well and are well known for their songs. Males have the largest documented song repertoire of all North American bird. This includes over 1100 types of songs. At young ages, birds most commonly use "alarm noises". Primary modes of perception include visual and tactile. Brown thrashers use mainly vision to find food and their tactile abilities to search for and manipulate food.
Communication Channels: acoustic
Other Communication Modes: mimicry
Perception Channels: visual ; tactile ; acoustic ; chemical
Brown thrashers are not listed as threatened or endangered in any part of their range. No management actions are known to increase or maintain populations. Dangers include pesticides, collisions with structures, and some degradation of habitats. These effects have yet to become harmful enough to cause concern.
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
Brown thrashers can be significant pests in fruit orchards and crop fields.
Negative Impacts: crop pest
Brown thrashers are one of the best and most spectacular singers of all North American birds. Avid bird watchers enjoy the chance to see and hear these birds.
Positive Impacts: ecotourism ; research and education
Ecosystem roles include competition with other birds for nesting sites and resources. Also these birds are prey for many snakes and other birds.
Commensal/Parasitic Species:
Brown thrashers eat insects, primarily beetles and other arthropods, fruits, and nuts. They forage for food on the ground in leaf litter below trees and shrubs. These birds sweep the soil and leaf litter with rapid side-to-side movements that scatter leaves. After sweeping a few times, they will probe the soil and litter with their beaks.
Animal Foods: insects
Plant Foods: seeds, grains, and nuts; fruit
Primary Diet: omnivore
Brown thrashers are found from southeastern Canada through eastern, central, and southeastern United States. Brown thrashers are the only thrasher species east of the Rocky Mountains and central Texas. During the breeding season brown thrashers primarily inhabit areas of southern Canada south to east central Texas. Migration is over short distances and at night. In winter, these birds migrate from the northern parts of their range into the southern parts of their range.
Biogeographic Regions: nearctic (Native )
Brown thrashers are found in warm, dry habitats, such as warm forest edges and dense thickets. They are also found in suburban and agricultural areas.
Habitat Regions: temperate ; terrestrial
Terrestrial Biomes: forest ; scrub forest
Other Habitat Features: suburban ; agricultural ; riparian
Year-to-year survival is age dependent for brown thrashers. Survival rate is approximately 35% for their first and second years, 50% between second and third years, and 75% between third and fourth years. Limitations to lifespan include disease (for example Salmonella tymphimurium), parasitism, and sometimes exposure to cold temperatures. The longest known lifespan in the wild is twelve years and in captivity, ten to twelve years.
Range lifespan
Status: wild: 12 (high) years.
Range lifespan
Status: captivity: 10 to 12 years.
Typical lifespan
Status: wild: 11.34 to 17.61 years.
Average lifespan
Status: wild: 14.14 years.
Average lifespan
Status: captivity: 12 years.
Adults have rufous upperparts and white underparts with a long, black tail. They have long, straight bills and yellow eyes. Males and females are alike in size and coloration. They are from 23.5 cm to 30.5 cm long, with wingspans of 9.4 to 11.1 cm long. The young appear the same except their upperparts are spotted and their eyes are gray. There are two sub-species, brown thrashers (T. rufum rufum) and long-billed thrashers (T.rufum longirostre). Long-billed thrashers are unique in their dull upperparts, gray head, orange eye, and long, straight bill.
Range mass: 89 (high) g.
Average mass: 68.8 g.
Range length: 235 to 305 mm.
Range wingspan: 94 to 111 mm.
Other Physical Features: endothermic ; homoiothermic; bilateral symmetry
Sexual Dimorphism: sexes alike
Gray catbirds (Dumetella carolinensis) have been documented visiting brown thrasher nests to break the eggs. Two hypotheses are proposed to explain this heterospecific egg destruction behavior: resource competition and egg predation. These birds both live in shrubs and have similar timing in breeding. They compete for the resources of this habitat. Once the catbird has broken the egg, usually it will consume the contents. This egg consumption is consistent with the proposed egg predation hypothesis. The eggs of brown thrashers are also preyed on by many species of snakes. Adults and nestlings are preyed on by falcons.
To respond to predation, brown thrashers have a few natural defenses. Adults are aggressive and often chase predators from the nest. Adults will use their bill to hit predators, these are large birds and they can cause significant damage to small and medium-sized predators. Other defenses include flapping theirwings and vocalizations.
Known Predators:
When males arrive at the breeding grounds they establish a territory. In the southern parts of their range breeding starts in February and March, in the northern parts, breeding starts in May and June. Soon after this, pairs are formed and they begin to build a nest. Mates find each other with calls, most commonly using a call similar to a "tick" or "tchuck". Once the bond is formed and the nest is built, the pair will mate.
Mating System: monogamous
Brown thrasher breeding seasons vary with geographic region. Birds in the southern region breed from February to March; while those in the northern region breed from May to June. Brown thrashers lay three to five eggs each breeding season. Incubation takes about two weeks, once the eggs have hatched, nestlings take from 9 to 13 days to fledge. Independence is reached 17 to 19 days later.
Breeding interval: Brown thrashers breed once yearly.
Breeding season: Breeding season varies geographically. Southern populations breed in February and March, northern populations birds breed in May and June
Range eggs per season: 3 to 5.
Range time to hatching: 11 to 14 days.
Range fledging age: 9 to 13 days.
Range time to independence: 17 to 19 days.
Key Reproductive Features: iteroparous ; seasonal breeding ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Average eggs per season: 4.
Both parents incubate, brood, and feed nestlings. They incubate by sitting tightly on the nest and slip off when disturbed. During the incubation period, the female does the majority of the incubating. Both parents feed the chicks.
Parental Investment: altricial ; pre-fertilization (Provisioning, Protecting: Female); pre-hatching/birth (Provisioning: Female, Protecting: Male, Female); pre-weaning/fledging (Provisioning: Male, Female, Protecting: Male, Female)
