Gregarious for most of the year, American goldfinches finally pair off by mid summer, much later than most songbirds. Their late nesting behavior is timed to coincide with the lifecycle of native flora; using thistle down to construct their cup-shaped nests, these finches also wait to raise their young until weed and grass seeds are most abundant.
Due to the bright yellow summer plumage of the adult male, American goldfinches are often called "wild canaries." A favorite of naturalists and backyard birders, these small, common birds are easily attracted to Niger "thistle" feeders, where they are more than capable of feeding upside down. In late July or August, they place their nest in the fork of a sapling branch or shrub; a single clutch of 4-6 pale blue eggs is laid each year and the young are fed with softened, regurgitated seeds. By mid September, the males are molting to their dull, gray-olive plumage and the goldfinches begin to gather in large flocks once again.
