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. (Howard and Moore, 1991; Robbins, et al., 1983)
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. (Cavitt and Haas, 2000; Peterson, 1999; Peterson, 2001)
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. (Cavitt and Haas, 2000; Dunning, 1993; Godfrey, 1986)
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. (Cavitt and Haas, 2000; Fergus, 2004)
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. (Cavitt and Haas, 2000; Ehrlich, et al., 1988)
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. (Cavitt and Haas, 2000; Ehrlich, et al., 1988)
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. (Cavitt and Haas, 2000; Ehrlich, et al., 1988)
These birds are usually territorial and are found in pairs or with offspring during the breeding season. They compete with other birds for habitat and nesting areas. This competition results in hostile encounters with birds like gray catbirds (Dumetella carolinensis). Most often these encounters are instigated by males. During winters brown thrashers often displace other birds from their feeding areas. The name "thrasher" may come from the bird's habit of thrashing ground litter with its bill. Migration is over short distances and at night. (Cavitt and Haas, 2000; Fergus, 2004)
Territory-mapping studies indicate variation in territory densities. Most activites of a pair are confined to territories. (Cavitt and Haas, 2000)
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. (Cavitt and Haas, 2000; Ehrlich, et al., 1988)
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. (Cavitt and Haas, 2000)
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. (Cavitt and Haas, 2000; Rivers and Sandercock, 2004)
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. (Cavitt and Haas, 2000; Rivers and Sandercock, 2004)
Ecosystem roles include competition with other birds for nesting sites and resources. Also these birds are prey for many snakes and other birds. (Cavitt and Haas, 2000; Ehrlich, et al., 1988; "Mockingbirds", 1985; Fergus, 2004)
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. (Ehrlich, et al., 1988)
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. (Cavitt and Haas, 2000)
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. (Cavitt and Haas, 2000; Ehrlich, et al., 1988; Fergus, 2004)
Tanya Dewey (editor), Animal Diversity Web.
Phillip Gray (author), Kalamazoo College, Ann Fraser (editor, instructor), Kalamazoo College.
living in the Nearctic biogeographic province, the northern part of the New World. This includes Greenland, the Canadian Arctic islands, and all of the North American as far south as the highlands of central Mexico.
uses sound to communicate
living in landscapes dominated by human agriculture.
young are born in a relatively underdeveloped state; they are unable to feed or care for themselves or locomote independently for a period of time after birth/hatching. In birds, naked and helpless after hatching.
having body symmetry such that the animal can be divided in one plane into two mirror-image halves. Animals with bilateral symmetry have dorsal and ventral sides, as well as anterior and posterior ends. Synapomorphy of the Bilateria.
uses smells or other chemicals to communicate
humans benefit economically by promoting tourism that focuses on the appreciation of natural areas or animals. Ecotourism implies that there are existing programs that profit from the appreciation of natural areas or animals.
animals that use metabolically generated heat to regulate body temperature independently of ambient temperature. Endothermy is a synapomorphy of the Mammalia, although it may have arisen in a (now extinct) synapsid ancestor; the fossil record does not distinguish these possibilities. Convergent in birds.
forest biomes are dominated by trees, otherwise forest biomes can vary widely in amount of precipitation and seasonality.
offspring are produced in more than one group (litters, clutches, etc.) and across multiple seasons (or other periods hospitable to reproduction). Iteroparous animals must, by definition, survive over multiple seasons (or periodic condition changes).
makes seasonal movements between breeding and wintering grounds
imitates a communication signal or appearance of another kind of organism
Having one mate at a time.
having the capacity to move from one place to another.
the area in which the animal is naturally found, the region in which it is endemic.
an animal that mainly eats all kinds of things, including plants and animals
reproduction in which eggs are released by the female; development of offspring occurs outside the mother's body.
Referring to something living or located adjacent to a waterbody (usually, but not always, a river or stream).
scrub forests develop in areas that experience dry seasons.
breeding is confined to a particular season
reproduction that includes combining the genetic contribution of two individuals, a male and a female
living in residential areas on the outskirts of large cities or towns.
uses touch to communicate
that region of the Earth between 23.5 degrees North and 60 degrees North (between the Tropic of Cancer and the Arctic Circle) and between 23.5 degrees South and 60 degrees South (between the Tropic of Capricorn and the Antarctic Circle).
Living on the ground.
defends an area within the home range, occupied by a single animals or group of animals of the same species and held through overt defense, display, or advertisement
uses sight to communicate
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