Brood parasitism: Eastern Phoebe (Sayornis phoebe) nest with begging Brown-headed Cowbird (Molothrus ater) nestling. Cowbird nestling is large, has red gape, eyes open. Phoebe nestlings are smaller, have yellow gape, eyes still closed, New York, USA
Slide # B105-41 (Digitally retouched image)
Digitally retouched image (background cleaned up)