Wood Thrush and Cowbird Nestling.
According to Cornell, link above: Once confined to the open grasslands of middle North America, cowbirds have surged in numbers and range as humans built towns and cleared woods.
Wood Thrush and Cowbird nestling. Better enlarged.
In response to a query, Cornell NestWatch Project Assistant Kenyon Stratton: As for the cowbirds, it is great that the Wood Thrush actually has chicks that are so well developed. Often times, the eggs do not hatch or the young die very young. However, because these chicks are almost completely feathered they are doing well. Once the cowbird chick does fledge the adults might not spend much time caring for it off the nest. Often, cowbird chicks are able to go their own way once they fledge. But, even if the adult does have to care for the cowbird off the nest she will continue to care for her own young as well. Right now, I’m thinking that all of these chicks will successfully fledge.
A BETTER WHITE-BALANCED RENDITION OF THIS PHOTO IS AVAILABLE BY EMAIL.