The feathers of a male goldfinches become brightly colored each spring. which best describes why the color of the feathers change each year?

American Goldfinch follows this pattern. Beginning in September, and continuing for six to eight weeks, they molt all of their feathers, ending up with a completely new and pristine set of feathers (and drab colors) as they head into the winter. In the spring, as they grow new body feathers the males especially transform into bright yellow breeding plumage, but the wing and tail feathers remain from the previous fall. As these wing feathers get older the pale buff edges fade to white and disintegrate, so that by the end of the summer the wings look essentially all black. And in September another complete molt begins.

Explanation:

maritime tropical may be your answer.