Woodland Birds, Pacific Northwest
The black throated gray warbler is a small songbird that breeds in open coniferous and mixed forests on the BC Coast, especially in alder and maple forests mixed with conifers. They winter in Mexico and the south western United States.
They have a black crown touched with yellow, a white face along with a thin pointed bill, white wing bars, grey upper plumage with black streaks on their back and white under parts with black streaks on their flanks. Adult males have a black throat and cheeks and the females have a white throat and dark grey cheeks.
The open cup nest is usually situated on a horizontal tree branch. The female lays 3 to 5 eggs. Both parents feed the young.
They mostly feed on insects with a love of caterpillars. They forage in low foliage but may also hover and capture insects in flight.
Much of the breeding rituals of the Black Throated Gray Warblers is still unknown. They are most likely monogamous, and nests are typically situated on horizontal branches from 2 to 10 meters off the ground. Nests are open bowls constructed of grass, plant fibers, and moss, with a lining of animal fur and feathers. The female builds the nest and incubates up to 4 eggs, although the incubation period is not known. Once the young hatch, both sexes feed them. It is not known when the young fledge, or for how long the parents feed them. In some areas, as soon as the young can fly and find their own food, they leave the breeding grounds for higher elevations.
The population status of the Black Throated Gray Warblers appears stable. They are one of the favorite birds to be parasitised by the Brown Headed Cowbirds, but the rates of parasitism seem relatively low. Settlement and forest management may have benefited the Black Throated Gray Warblers, because this development has increased the amount of hardwood growing in these historically coniferous zones. More study is needed on the status of the Black Throated Gray Warbler population range the BC Coast.