Photo courtesy Charles Martinez
This week’s Bird of the Week, compliments of the Weminuche Audubon Society and Audubon Rockies, is the American goldfinch.
Many songbirds instinctively time migration to take advantage of peak insect hatches at distant breeding grounds. Some fly great distances to raise young in boggy northern regions filled with insects. Even seed-eating birds usually rely on the extra protein provided by insects to fuel the growth of nestlings. In a warming climate, northern insects are hatching earlier, sometimes leaving migratory birds out of sync with the availability of this important food source.
Insect availability is not one of the challenges faced by American goldfinches. These birds are entirely vegetarian, only eating an insect on occasion. They feed on the seeds of weeds, flowers, grasses and trees like the alder. Favorite seed heads are those of thistle, sunflower and flowers in the aster family.
American goldfinches breed later than most North American birds. Not dependent on insect availability, they time nest building and egg laying to take advantage of the availability of fibrous seeds like those of milkweed and thistle. Nestlings are fed a mixture of regurgitated seed matter. Cowbird chicks that hatch in a goldfinch nest cannot survive on this vegetarian diet.
The bright yellow color, offset by a black forehead, tail and wings, of the spring and summer male have earned him the name of wild canary. Females are a duller green-yellow color and lack the black forehead. In winter, both sexes molt to a grayish-brown color.
Feeders stocked with sunflower seeds and nyjer thistle, and flowering plants gone to seed, will attract these beautiful birds to your yard.
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