Why do cuckoos cuculus canorus use so many species of hosts?

Abstract

Observations of territorial behaviour at Dungeness, Kent, indicated that territory-holding Cuckoos expelled non-territorial females from the vicinity of their host species’ breeding habitat but tolerated them at the periphery of the territory. Paired males assisted their territory-holding mates in expelling intruding females but associated with these outside the territory and may have mated with them. Non-territorial females may well have had the same host preference as territory-holders, if so, they were denied access to the nests of their chosen species and thus obliged to lay elsewhere. This may explain recent parasitism of Whitethroat and Skylark at Dungeness and the wide range of species chosen as Cuckoo hosts in Britain. © 1986 Taylor & Francis Group, LLC.