The American Goldfinch is one of the last species in our area to build a nest, lay eggs and raise young. From March through August, American Goldfinch males are among the brightest songbirds in our area. Their lemon-yellow plumage is tied to a diet rich in carotenoids; the brighter the feather and the more orange the bill, the more attractive they are to a mate.
American Goldfinches commonly nest at the edge of fields, open deciduous woodlands, and riparian areas. A pair defends a small area near the nest, but not a large territory, allowing for several pairs to share the same locale tied to habitat and food resources. The female begins nest-building in late June or July. She will lay 4-5 eggs in a small cup nest made of fine grasses and a plush lining of soft cottony fibers and hairs. Incubation takes about 12-14 days and once hatched, nestlings are fed a seed-rich diet. This food is unsuitable for any parasitic cowbird chicks that might find themselves in the care of the goldfinches, and usually leads to the invaders’ demise. American Goldfinch chicks fledge in about 12 days, and the young will follow the parents for about three weeks, gradually becoming more independent. Occasionally, the female leaves the first brood so the male will finish raising the chicks, and she flies off with another mate to start a second brood.
Watch for large flocks forming in August, often consisting of many buff-colored young and a few adults molting back into winter (basic) plumage. A garden planted with a native meadow can attract over 100 American Goldfinches.
The closely related Lesser Goldfinch is a slightly smaller and less-bright goldfinch found in open woodlands—especially woodlands containing Oregon White Oak—but also in shrubby habitat and weedy fields. What they lack in stature, they make up for in voice: these bubbly songsters are known to include mimicked phrases of dozens of other species—from kestrels to wood pewees—in their repertoire. The Lesser Goldfinch was probably not present in the Willamette Valley prior to the 1940s, and has dramatically increased in our area over the past 40 years, most notably in urban environments. This range expansion may have been aided as logging activity created more open habitat and bird-feeding stations helped fuel an increase in winter survivorship.
Like their cousins, Lesser Goldfinches are semi-colonial breeders, with many nests found in a relatively small area. Nesting season begins in April, but can last through July. The pair produces about 4 eggs in a small cup nest composed of grasses and lined with some soft plant fibers and fur. The chicks hatch in about 12 days, then fledge in another 12 days. The young will stay with the parents for about a month.