Geography/Habitat:

The Black-and-White Warbler, (Mniotilta varia), was first described by Linnaeus in 1766 on an expedition to Hispaniola, (now the Dominican Republic). It is the only member of the genus Mniotilta. It is monotypic but occasionally hybridizes with Cerulean and Blackburnian War-bler. 

Black-and-White Warblers are migratory, breeding throughout central and eastern Canada, and the eastern United States. They winter in Texas and Florida, throughout Mexico, the Caribbean islands, Central America, and down to Venezuela, Colombia and northern South America. They appear as a year-round resident in some areas, and some individuals are only very short distance migrants (notably in Texas).

Their preferred habitat is mature deciduous woodlands, but they are typically found anywhere there are insect-laden deciduous trees, especially during migration. Black-and-White Warblers feed on all sorts of insects, but caterpillars, flies, bugs, beetles and spiders are preferred. They forage tirelessly on the bark, often going downwards head first (nuthatch or creeper like) of trees and feed voraciously. They are the only North American warbler with this distinctive feeding behavior. A close examination shows a highly modified and lengthened rear toe that has evolved to enable and enhance this feeding behavior.

A small nest composed of twigs and grass and lined with hair and fern is constructed at the base of tree trunks or stumps in which 4-6 creamy white eggs are laid, usually in May to July. The female incubates these for 10-12 days, and it is a further 12 days before the chicks leave the nest. The parents will feign injury to lure predators away if the nest is threatened. 

Identification:

A very distinctive all black and white striped warbler, (occasionally with buffy flanks), the male is more boldly striped with distinctive black auriculars and throat with a white eyebrow. The female is similar but more subdued and lacks the black auriculars and throat.

Black-and-White Warblers have a distinctive song with a two syllable phrase repeated in series 5 to 10 times “ weesa weesa”. Its call is sharp and rattling “schtick” again repeated in series.

Interesting Facts:

·      Black-and-White Warblers are not currently officially listed as threatened but their population is decreasing markedly down about 35% since the 1970s.

·      The only member of the genus Mniotilta which is translated “a moss plucker”- a perfect description.

·      They are often known as black-and-white creepers, and can be unusually aggressive for a warbler, often fighting with nuthatches and chickadees.

·      A group of warblers is known as a dichotomy, a distinction, or an integration.