|Male (right) and Female (left)|
Both male and female Goldfinches are yellow, though the males are far more vibrant, especially during the breeding season. They are the only finch species to molt twice a year, and breed relatively late for a songbird.
American Goldfinches are notable for their very strict vegetarian diet. While many bird species feed on the occasional insect, Goldfinches eat exclusively seeds. This has an interesting affect on the Brown-Headed Cowbird. These birds sometimes lay eggs in Goldfinch nests, but the hatchlings are unable to survive due to the all-seed diet the Finches provide for their young.
Goldfinches are not a threatened species. They have a massive range spanning some 5 million square miles (about 8 million square km).