Sometimes she does, and she uses her beak to put a hole through the shell and then ejects the egg out of the nest. But surprisingly often, that's not the case. And there's a number of reasons for why ...

Every cuckoo is an adopted child—raised by foster parents, into whose nest the cuckoo mother smuggled her egg. The cuckoo mother is aided in this subterfuge by her resemblance to a bird of prey. There ...

Perhaps the most famous nest hijacker in the bird world, the common cuckoo has even given rise to the phrase “cuckooing.” A female cuckoo carefully watches her host bird, usually small songbirds like ...

Female adult Common Cuckoos appear in two color morphs, shown here as half of the rufous (hepatic) form (left) and half of the gray morph (male-like, right). Several species of cuckoos, a genus of ...

Every cuckoo is an adopted child -- raised by foster parents, into whose nest the cuckoo mother smuggled her egg. The cuckoo mother is aided in this subterfuge by her resemblance to a bird of prey.

Sexual dimorphism—the visible difference between females and males—can be seen in diverse animals, including humans. One intriguing aspect of this phenomenon is sex-limited polymorphism, where one sex ...