I talk to my good friend Larry Walthall just about everyday. In the last month or so he has been seeing a few American goldfinches at his bird feeder. They are commonly called wild canaries.
American goldfinches, which are the state bird of Iowa, New Jersey and Washington, are one of the latest breeding songbirds. They begin nesting from late July into September. This coincides with the abundance of their chief food source - seeds.
Almost any sort of seed will do. They readily feed on a wide variety of weed, flower, tree and grass seeds as well as buds, sap, berries and less commonly, insects. But, thistle seed is their favorite food. The American goldfinch’s scientific name is carduelis (from the Latin word carduus which means thistle) tristis.
Unlike many birds, American goldfinches molt their feathers twice a year. The male in breeding plumage is easy to recognize: bright yellow with black wings and cap. Like other common feeder birds such as northern cardinals, the American goldfinch is a sexually dimorphic species with females much more drab than the eye-catching male.
After nesting in the fall, they molt again and male and female look more alike with feathers of brown, olive and dull yellow-green accented by buff or white markings. The change in the males plumage leads some people to believe that American goldfinches are absent in the winter when in fact they may still be around- just in duller plumage. When the males molt back from drab to brilliant it seems as if they just appear from nowhere.
Four subspecies are recognized, separated by size, wing and tail markings and color intensity.
Many southern populations are resident, but northern populations are short distant migrants, traveling during the day in sizable flocks. In winter, flocks wander nomadically in search of food and are common visitors at backyard bird feeders. Resident flocks may move as much as 4-6 miles between multiple feeding sites.
Feathers are much more dense in the fall molt which provides additional layers of insulation to help keep them warm throughout the winter.
Since finches are granivorous (mostly seed eating diet) they also have other adaptations such as a strong conical bill that easily gathers and splits seeds and dexterous legs and feet which allow them to scramble up and down plant stems and hang from seedheads while feeding thereby accessing seed sources unavailable to other birds.
The American goldfinch male courts a female through flight displays and song. When a female accepts a male as a mate each flies in wide circles while the male sings.
The male then selects a territory, often close to several other goldfinch pairs in a loose colony. The close proximity of the pairs may help in defense against predators.
The female builds the nest, a tightly woven cup of plant fibers and spider webs lined with thistle down in a tree or shrub, usually 15’-17’ high. The nest is attached to the supporting twigs with spider web. American goldfinches nests are so well made that they have even been known to hold water.
While the female incubates the eggs by herself, the male feeds her on the nest. After the chicks hatch (in about 12 days) the female in turn feeds her chicks. As the nestlings grow, both parents feed them directly, but the male gradually takes over feeding the young birds. Nestlings fledge in about 12 days. Since they begin nesting late, American goldfinches usually only produce one brood of four to six eggs per season. It is estimated there are about three males for every two females because males live longer.
The American goldfinch is one of the very few species not affected by the brown-headed cowbird which are parasitic nesters. Cowbirds do not build a nest of their own. It has been documented that the female cowbird lays eggs in as many as 220 different species’ nests. The incubation period for brown-headed cowbirds is generally shorter than the host nest species. The cowbird egg hatches first, chicks develop faster, and the cowbird chick tosses out other eggs or nestlings of the host species. Any cowbirds that hatch in an American goldfinch nest usually die of starvation because goldfinches feed regurgitated seeds to their young, a diet that fails to meet a cowbird’s nutritional requirements.
“We still do not know 1/1000 of 1% of what nature has revealed to us.” -Albert Einstein
