Black-and-white warblers are small birds that are black and white all over. They have a black crown with bright white stripes behind each eye, a black-and-white back, and a grayish tail with white spots at the corners. They weigh 9 to 15 g and are 11 to 13 cm long. Black and white warblers have a long back claw on each short leg. These help them to climb around on branches and trunks. Their bills curve slightly downward. This shape helps them when they are probing in bark and mosses for food.
Black-and-white warblers breed throughout the eastern United States and much of Canada. They spend the winter in southern Florida, Mexico, Central America, the Caribbean Islands and northern South America. (Dunn and Garrett, 1997; Ehrlich, et al., 1988)
Black-and-white warblers breed in deciduous and mixed deciduous-conifer forests. They prefer forests with large trees and an understory of smaller trees and shrubs. In winter, black-and-white warblers can be found in a variety of forest types, as well as woodland borders, gardens, and coffee plantations. (Dunn and Garrett, 1997; Ehrlich, et al., 1988)
Black-and-white warblers are probably monogamous.
Black-and-white warblers breed between April and August. Males arrive first in the spring. Soon after arriving, they establish a territory, and then begin looking for a mate. The males try to attract a female by following her around, singing and showing off their feathers. They may also perch near the female and flutter their wings.
Once a pair has formed, the female builds the nest. The nest is cup-shaped, and is made of leaves and grasses. Nests are built on the ground at the base of a tree or next to a fallen log. They are usually hidden under dead leaves or branches.
When the nest is finished, the female lays 4 to 6 (usually 5) white eggs with brown flecks. She incubates them for 10 to 12 days. The male sometimes brings food to the female while she is incubating. After the chicks hatch, both parents feed them and defend the nest. The chicks leave the nest after 8 to 12 days. They stay in their parents' territory for 2 to 3 weeks before leaving.
Both male and female black-and-white warblers take care of their young. The female builds the nest and incubates the eggs. After the chicks hatch, both parents feed and protect them. (Kricher, 1995)
The oldest known black-and-white warbler lived at least 11 years. Most black-and-white warblers probably do not live nearly this long. ()
Black-and-white warblers are diurnal (active during the day). They are also migratory. All black-and-white warblers migrate in the spring and fall.
Black-and-white warblers are territorial. They defend territories during the breeding season and sometimes in the winter too. During migration and winter, black-and-white warblers are more social. They often join feeding flocks with other bird species. (Burtt, 1980; Dunn and Garrett, 1997; Ehrlich, et al., 1988; Kricher, 1995)
The home range of black-and-white warblers is unknown.
Black-and-white warblers use calls and body signals to communicate. The songs of black-and-white warblers are high-pitched and squeaky. The most common song sounds like wee-see repeated 6 to 10 times. It can last up to 3 seconds. To some people, this song sounds like a squeaky wheel. Black-and-white warblers also use call notes, like chip and tik to communicate. (Dunn and Garrett, 1997)
Black-and-white warblers are insectivores. They mostly eat insects that they find on the trunks and limbs of trees. Common foods that black-and-white warblers eat include caterpillars, flies, bugs, beetles, borers, spiders, larvae, and egg masses.
Black-and-white warblers are the only wood-warblers that forage for most of their food on bark. They creep along branches and trunks from the ground up to the canopy, picking and probing into cracks and crevices with their bills. They even hang on the undersides of branches and creep down tree trunks head-first. Because black-and-white warblers find most of their food in tree trunks, they don't have to wait for insects to emerge in the spring. This means that they can arrive at the breeding grounds earlier in the spring than other warblers. Black-and-white warblers sometimes forage by catching insects in the air and searching for them amongst leaves. (Dunn and Garrett, 1997; Ehrlich, et al., 1988; Kricher, 1995)
There is not much information available about predation of black-and-white warblers. As a ground nesting species, black-and-white warblers are probably vulnerable to many different predators, especially during the breeding season. Common forest animals such as blue jays, deer mice, eastern chipmunks, northern flying squirrels, red squirrels, raccoons and black bears are likely to be predators of black-and-white warblers. (Ehrlich, et al., 1988)
Black-and-white warblers affect the populations of insects they eat. They also provide food for their predators. Finally, they are habitat for parasites such as feather mites, lice and blood parasites. (Ehrlich, et al., 1988)
We do not know of any way that black-and-white warblers harm humans.
We do not know of any way that black-and-white warblers affect humans.
Black-and-white warblers are a fairly common forest bird. There are about 14,000,000 black-and-white warblers across their range. Black-and-white warblers prefer large areas of forest. One of the major threats facing them is forest fragmentation. Other things that may harm black-and-white warblers include nest parasitism by cowbirds and pesticide poisoning.
Kari Kirschbaum (author, editor), Animal Diversity Web.
Jacob Foster (author), University of Michigan-Ann Arbor, Terry Root (editor), University of Michigan-Ann Arbor.
Anderson, K., H. Maxfield. 1967. Warbler returns from southeastern Massachusetts. Bird Banding, 43: 218-233.
Blake, C., J. Cadbury. 1969. An old warbler. Bird Banding, 40: 255.
Burtt, E. 1980. Overwing and underwing head scratching by a male Black-and-white Warbler (Mniotilta varia). Ibis, 122: 541.
Dunn, J., K. Garrett. 1997. A field guide to warblers of North America. Peterson Field Guide Series. NY: Houghton Mifflin Co.
Ehrlich, P., D. Dobkin, D. Wheye. 1988. The birder's handbook: A field guide to the natural history of North American birds. NY: Simon & Schuster Inc.
Kricher, J. 1995. Black-and-white Warbler (Mniotilta varia). Pp. 1-20 in A Poole, F Gill, eds. The Birds of North America, Vol. 158. Philadelphia, PA: The Academy of Natural Sciences, and Washington DC: The American Ornithologists' Union.