“In Britain the loss of these kinds of defenses makes the birds once again targets for attack by cuckoos, thereby continuing the process of coevolutionary alternation among hosts.”

“In the process called coevolutionary alternation, one species coevolves with several other species by shifting among the species with which it interacts over many generations.”

“Such studies, however, require that intact biological communities are preserved as precious natural laboratories for understanding the coevolutionary process.”