Black and White to Pegapalo: The Two Worlds of a Warbler
Watching warblers on the wintering grounds is always amazing for me. Because I am most familiar with their breeding habits and habitats, they seem like completely different birds. But they are as at home here in the Dominican Republic where I stand as they are in the New England woods.
A Cape May Warbler forages in a bush in dry shrublands, a Black-throated Blue Warbler calls in a wet rainforest on a mountain slope. An American Redstart flits from fruit tree to fruit tree in an arboretum, a Blackpoll calls from a tree in the middle of the city on its way to South America, and a Black-and-white Warbler creeps down a limb, jumps to a hanging vine working its way downward foraging for insects.
The Black-and-white Warbler has an unusually long hind toe and claw on each foot, allowing it to walk on the surface of tree bark at any angle. They search trunks and branches for insects with pokes, prods and prying, which gives them their Spanish name here, Pegapalo – hitting stick. Most of their foraging time is spent on tree trunks and large, inner branches where fewer wood-warblers forage, effectively avoiding interspecific competition.
They are often found among mixed species foraging flocks comprised of other migratory and resident songbirds. As a flock of birds comes into their territory foraging, they tend to join and move with the group. This may have two benefits. It may reduce the chances of predation as more eyes and ears are on the alert, and it may increase foraging efficiency as the crowd flushes prey items.
Black-and-whites are most abundant in intact, large forests, but they are able to make a living in disturbed habitats too. I have seen them in city parks, backyards, and farms. Some of my colleagues in the Dominican Republic have found that 65% of Black-and-White Warblers kept territories on shade coffee plantations smaller than 25 acres. An amazing 40% of them returned to the same plantation a year or more later. That cup of shade grown, organic coffee in your hand is clearly important for Pegapalos.
In April and early May they’ll get the urge to migrate and soon they will be back at my house in New England singing their squeaky-wheel song and I’ll remember their southern home once again.