Avian Foster Care The brown-headed cowbird doesn't look like much of a villain. But this species and many other birds, as well as some insects and fish, are "brood parasites"—a phrase ecologists use to describe animals that skip out on parenting by depositing their young in the care of another. The unwitting foster parent raises the parasitic young as if they were its own and bears the considerable cost of feeding and protecting the babies. What tactics do animals use to dupe others into parenthood? Here, take a look at some of the tactics, from grisly competition to more subtle deception.—Rachel VanCottCaption: The mottled cowbird egg seen here looks nothing like the host robin's eggs, but the brood parasite will be raised right along with the rest of the robin family.