American Goldfinch - Behavior

Behavior

The American Goldfinch is gregarious during the non-breeding season, when it is often found in large flocks, usually with other finches. Flocks generally fly in an undulating pattern, creating a wave-shaped path. During the breeding season, it lives in loose colonies. While the nest is being constructed, the male will act aggressively toward other males who intrude into his territory, driving them away, and the female reacts in the same way toward other females. This aggressiveness fades once the eggs have been laid.

The American Goldfinch does not act aggressively toward predators within its territory; its only reaction is alarm calling. Predators include snakes, weasels, squirrels, and Blue Jays, which may destroy eggs or kill young, and hawks and cats, which pose a threat to both young and adults. As of 2007, the oldest known American Goldfinch was 10 years and 5 months old.