The American RedstartSetophaga ruticilla is a New World warbler and is unrelated to the Old World redstarts. It derives its name from the male's red tail, start being an old word for tail. It has a wingspan of 6.3 to 9.1 in. The breeding males are unmistakable, jet black above and large orange-red patches on their wings and tails. Their breast sides are also orange while the rest of their under parts are white.
The orange patches of the breeding males are replaced by yellow in the plumages of the females and young birds. Orange and yellow coloration is due to the presence of carotenoids; males possess the red carotenoid Canthaxanthin and the yellow carotenoids Canary Xanthophyll A and B, all of which mix together to produce an orange color, while the females possess only the yellow carotenoids. Recent research indicates that an age and sex effect on observed color attributes of hue, brightness, and saturation exists in American Redstarts, with the exception for saturation, which only showed an age effect. Their song is a series of musical see notes. Their call is a soft chip.