Helpers at birds' nests

the long version

"In Helpers at Birds' Nests, renowned naturalist and ornithologist Alexander Skutch provides vivid, detailed accounts of a remarkable aspect of bird behavior - the aid that one bird gives another who is neither its mate nor its dependent young and who may even belong to a different species."--BOOK JACKET. "Skutch describes the cooperative behavior of more than fifty families of birds. Each family is introduced by a brief sketch of its distribution and outstanding features, followed by intimate, nontechnical accounts of the helpful behaviors that have been most carefully studied. Skutch considers the significance of helpful birds and discusses the theoretical aspects of cooperative breeding, its evolution, kin selection, altruism, and demography."--BOOK JACKET.