Meet the brown thrasher- red-brown feathers and beady yellow eyes, attached to a slender body and spindly legs. It looks fierce, and it is. If it sees people or animals too close to its nest, it attacks. If a brown-headed cowbird tries to lay its eggs in the brown thrasher’s nest, it chases it away. And if any other birds get on its nerves, it can just open its beak and scare them away with the call of a hawk or the hiss of a snake. As a bird enthusiast, first-time birdwatcher, or curious student, the brown thrasher is a particularly interesting bird to observe; in the backyard, on a hike or on the edge of any woodland.
The brown thrasher does not call attention to itself, and birders might not notice it immediately. Although, once an observer has seen the bird, it has plenty of obvious physical features that can help identify it (“Brown Thrasher”).
Most feathers are brown in color with a reddish tinge. Many sources will identify its coloring as “rufous” (“Brown Thrasher”).
The underside is off-white and flecked with very distinct dark streaks. These markings are a major clue when identifying the brown thrasher (“Brown Thrasher”).
The tail feathers are very long and straight. Like the feathers of the posterior and head, they are reddish brown (“Brown Thrasher”).
The brown thrasher has a long, straight beak with very little curve. The beak is dark gray with few easily distinguishable characteristics (“Brown Thrasher”).
The brown thrasher’s eyes are beady and yellow. Their color and tendency to appear as though staring can give the bird an eerie, harsh expression (“Brown Thrasher”).
Differences Within the Species
In terms of appearance, males and females are virtually identical. There are no major definable differences between the two genders (Gray).
In the juvenile stage of a brown thrasher’s lifespan, the bird does not look quite the same as it will when fully developed (Gray). It has
- black eyes
- smaller streaks on the breast
- pinker legs
- and a shorter beak.
Brown thrashers that live in eastern North America are smaller than those of the western Great Plains (“Brown Thrasher”).
In order to survive in a hostile world full of predators and other natural threats, the brown thrasher has adapted to its environment and lifestyle. It is well-camouflaged, and every part of its body is specifically designed to further its chances of survival.
The brown thrasher’s red-brown feathers help it to blend in with the shrubs and thickets it can usually be found in (“Brown Thrasher,” 2017).
Camouflage is one of the most common ways to avoid being eaten by predators. When a bird can hide from danger, it doesn’t need to be faster, stronger, bigger, or fiercer than the danger.
Brown thrashers that spend most months in the northern United States (and some parts of southern Canada) live in colder climates. When winter comes, these areas are too cold for them to survive easily, so they migrate to Mexico and the southern US (“Brown Thrasher,” 2017).
Northern brown thrashers migrate to stay warm and to find food that might be scarce in the north during the winter (“Brown Thrasher,” 2017)
Brown thrashers that raise their young in southern parts of the USA do not need this adaptation, because the weather there is warm enough for them even in the winter. (“Brown Thrasher,” 2017)
Brown thrashers, as members of the Mimid family, have the unique ability to mimic the calls of other birds (“Brown Thrasher,” 2017).
They can also mimic the sounds of predators, such as snakes and cats (Mayntz).
Mimicry can warn other birds and predators away from the nest. This protects the brown thrasher’s eggs and young (Mayntz).
The brown thrasher builds a nest for its eggs and young, which helps keep them safe. Without a nest, they are much more vulnerable to predators and other threats such as weather (“Brown Thrasher”).
The birds build their nests low to the ground (2-7’ up). This allows them to forage for food for their young without straying too far from the nest and leaving it unprotected (“Brown Thrasher,” 2017).
The nest is built out of sturdy, durable materials (“Brown Thrasher,” 2017) such as
- weeds and grass
- bark fibers
- and small roots.
The brown thrasher possesses a long, narrow beak (Gray).
This beak is a critical feature of the bird because it is perfectly shaped to fit its diet. The brown thrasher uses it when foraging through leaves for insects, and when eating berries & fruit (“Brown Thrasher”).
The beak can also be used to strike predators or other animals if they display threatening behavior. Brown thrashers have been known to draw blood from people and cats lingering too close to their nests (Gray).
Predators and prey
The brown thrasher is an omnivore, meaning it eats both plants and animals (specifically insects). Not only does it have to worry about finding food, it is also constantly threatened by a wide variety of predators.
Brown thrashers eat a wide variety of insects, which they find on the forest floor (“Brown Thrasher,” 2017). These insects may include
- and true bugs.
In addition to insects, the rest of the animal portion of its diet consists of
- and occasionally small lizards or frogs. (“Brown Thrasher,” 2017).
Berries and small fruits are eaten largely in the fall, when insects may be less common (“Brown Thrasher,” 2017).
Brown thrashers also eat nuts and seeds, primarily acorns, that they find lying on the ground in the spring and fall (“Brown Thrasher,” 2017).
While they are still in the nest, brown thrasher hatchlings and eggs are often eaten by the gray catbird (Gray).
Brown thrashers are preyed upon by quite a diverse range of snakes (Gray), such as
- eastern yellowbelly racers
- Great Plains rat snakes
- common king snakes
- milk snakes
- prairie king snakes
- black rat snakes
- bull snakes
- and even the non-venomous common garter snake.
They are also eaten by domestic cats all over the USA, and peregrine falcons where their habitats overlap (Gray).
Competition and symbiosis
In every ecosystem, organisms are constantly at war with each other over limited resources like mates, food, and shelter. The brown thrasher and its ecosystem are no different. This bird is engaged in a battle with several other birds, primarily over nesting space.
A well-known example of parasitism that involves the brown thrasher is the relationship between it and the brown-headed cowbird (“Brown Thrasher”). The brown-headed cowbird lays its eggs in the brown thrasher’s nest, destroying any eggs that are already there (“Brown Thrasher”). This poses a threat to the species (“Brown Thrasher”). Not only do cowbirds replace thrasher eggs with their own, they also leave and let the brown thrashers care for the foreign eggs (“Brown Thrasher”). Sometimes, brown thrashers will reject the eggs, destroying them, but brown-headed cowbirds are often raised by the unsuspecting birds (“Brown Thrasher”).
The brown thrasher competes similarly with the gray catbird. However, in this case, both birds play a parasitic role. They each lay their eggs in the nests the other one has already built (Gray). Like with the brown-headed cowbird, they will destroy any eggs they find there, but there’s a strange twist. The gray catbird is considered unique for its unusual habit of consuming the broken eggs. This behavior is uncharacteristic of a small songbird like the catbird (Gray). In addition, the two species will compete for areas in which to build their nests, since their criteria is very similar (Gray).
The brown thrasher also shares a similar diet with other birds, and may compete with them for limited supplies of food. One such case is with the wood thrush, a small bird that looks very like the brown thrasher, and eats much the same food. A large portion of both birds’ diets is made up of the same insects and berries (“Wood Thrush,” “Brown Thrasher,” 2017). Especially in winter, when food may be scarce, the two might compete for access to these limited resources (“Wood Thrush,” “Brown Thrasher,” 2017).
The brown thrasher also interacts in much the same way with the black-billed cuckoo. They both eat caterpillars and other insects (“Black-Billed Cuckoo,” “Brown Thrasher,” 2017). This might spark competition between them. They also eat many of the same berries and fruits, and these may be fought over in seasons when they are are primary food sources (“Black-Billed Cuckoo,” “Brown Thrasher,” 2017).
This page was created by a student at Oak Middle School as a part of our project called Bird is the Word. During this project our team partnered with the Mass Audubon Society and Broad Meadow Brook to create educational materials for their fundraising event called the Bird-a-Thon. Each student chose a bird to study. My bird was the brown thrasher. If you want to learn more about the brown thrasher and other birds, click below to check out the field guides made for the Audubon Society Bird-a-Thon. On this website you can also find glideshows about various other birds that can be seen in springtime Massachusetts.
shedding leaves every year
a complex set of relationships among the living and non-living resources in a particular area
a young bird that has not yet left the nest
not yet fully grown or mature
factors such as food, water, shelter, and mates that are finite and may result in competition between organisms
to move from one place to another in search of food, water, warmth, etc.
the imitation of behaviors or characteristics of other organisms or inanimate objects
a relationship between two organisms of different species in which one benefits and the other is harmed
the back of a bird's body
an animal that hunts other animals for food