Day 121: American Goldfinch

The American Goldfinch can be found throughout temperate North America. They are both sexually and seasonally dimorphic birds, undergoing a complete molt. Male birds are bright yellow in the summer and an olive color in the winter, while females are a dull yellow-brown color which brightens some during the summer.

We are fortunate to have several American Goldfinches that frequent a feeder on our porch. This time of year, they are particularly beautiful and fun to watch. Evidently, the bright yellow plumage of males is derived from carotenoid pigments, which birds and all other vertebrates acquire from their diet. Females prefer to mate with males that exhibit the brightest colors and thus may acquire the most skilled foragers.