An insect-like trill sounds repeatedly as you hike along the foot of a steep forested slope. But it’s no insect sounding off. If you wait patiently and quietly, you may see the singer: a handsome, buff-colored little warbler with a striking head pattern of alternating black and buff.
Contrary to its name, the Worm-eating Warbler doesn’t eat earthworms, but it does eat worm-like caterpillars, along with many other insects and spiders. Its most characteristic foraging behavior is “dead-leafing”—investigating and prying apart clumps of dead leaves hung up in branches and vines in search of the prey hiding there. They also glean among green leaves and the bark of trees and shrubs, like many other warbler species.
Forest fragmentation is the greatest threat facing the Worm-eating Warbler, both on its breeding grounds, where habitat loss exposes this ground-nesting species to nest predation and cowbird parasitism, and on its wintering grounds, where deforestation continues to reduce this bird’s wintering habitat.