March 2002 – vol. 95, issue 3, pp 101–115 ABSTRACT The sight of a small bird feeding a young Common Cuckoo Cuculus canorus, even as the cuckoo grows to ten times its own body weight, is astonishing.Why are the hosts apparently being so stupid? Do they accept cuckoo eggs and chicks because they have limited capabilities, and so will never evolve perfect defences? Or could hosts be gradually improving their defences in a continuing evolutio... This article is only available to registered users.To read more, please log in or purchase a subscription.