Thistles are favored, but this goldfinch readily feeds on a wide variety of weed, flower, tree, and grass seeds, as well as buds, sap, berries, and, less commonly, insects. This timing coincides with the abundance of their chief food source - seeds - in the late summer months. The American Goldfinch only begins nesting from late July to September, when most other songbirds are winding down breeding activity. It only begins to nest late in the summer, later than almost any other North American songbird. Unlike more rarely seen relatives such as the Pine Siskin and Evening Grosbeak, this widespread finch is a familiar sight year round, although most colorful in the breeding season. 'It has a definite personality exemplifying light-hearted cheerfulness, restlessness, sociability, and untiring activity.' Famed ornithologist Roger Tory Peterson made a similar observation: 'The responsibilities of life seem to rest lightly on the Goldfinch's sunny shoulders.' 'The goldfinch is an active little bird, always in the best of spirits,' observed noted naturalist Arthur Cleveland Bent early in the 20th century.
