When you're warbler hunting and a nuthatch catches your eye, look again! Black-and-white warblers are often mistaken for nuthatches due to their habit of creeping along tree trunks and large limbs, searching the bark for insects, spiders and their larvae. Easily observed and identified (unlike many of their cousins), they are aggressive birds, often chasing other insectivores from their feeding site.
Fairly common summer residents of deciduous and mixed forests in the eastern U.S. and southern Canada, they are often encountered in suburban woodlots and city parks during migrations. Once in their breeding territory, these agile arborists place their nest on the ground, hiding the cup of vegetation beneath understory shrubs, in rock crevices or among fallen limbs; nuthatches, by contrast, nest in tree cavities.
As chilly autumn nights spread south through the Continent, black-and-white warblers head for warmer climes where their prey remains active; their wintering grounds extend from South Texas to South America and from Florida to the Caribbean islands. Meanwhile, the hardy nuthatches of North America stay behind, managing to survive on hibernating insects, their pupae or their eggs and a variety of seeds.