Black-and-white Warbler

The standout feature of the Black-and-white Warbler is its habit of foraging along the trunks and limbs of trees like a nuthatch. They are aided in this behavior, as are nuthatches, by possessing a longer-than-usual hind claw and heavier legs. Their bill is also more strongly curved than those of most warblers, and helps them reach into bark crevices for caterpillars, beetles, insect eggs, and spiders. Even their genus translates as “moss plucker.” They are not restricted to foraging on bark however, and will frequently glean insects from foliage like other warblers.

For all the time they spend in trees, Black-and-white Warblers return to the ground to nest, building a neat cup of grass and pine needles at the base of a tree trunk or stump. The 3-5 eggs are incubated for 10-12 days, after which the parents feed the chicks for another 10-12 before they fledge.

Population trends for the Black-and-white Warbler are difficult to interpret. In much of the Northeast they were stable through the 1990s, only to drop precipitously through the early 2000s. After around 2005 they again stabilized or started to increase slightly. In contrast, trends to our west often involve a gradual increase in though the 1980s or beyond, and a more recent decrease. Since species has not been subject to extensive study, we don’t really know the degree to which it is sensitive to threats that affect other forest birds, particularly habitat fragmentation, increased predation, and changes in forest composition resulting from invasive species.