Interspecific Communication Signals in Parasitic Birds

Abstract

The visual conspicuousness of parasitic cuckoos is significantly less than in non-parasitic cuckoos. Dull plumages are prevalent in all groups of parasitic birds. In-conspicuousness and an absence of agonistic releasers is thought to increase the vulnerability of hosts to the brood parasites. Polymorphisir and an unusual degree of plumage variation in some parasitic cuckoos reduces the probability of recognition by hosts. The cuckoo Chryso-coccyx caprius is polymorphic in egg color and pattern; the tendency for morphs to be laid in host nests with matching eggs is statistically significant.