Breeding success of common cuckoosCuculus canorusparasitising four sympatric species ofAcrocephaluswarblers

Abstract

We investigated the level of parasitism, egg mimicry and breeding success of cuckoos parasitising four sympatric species ofAcrocephaluswarblers in southern Moravia, Czech Republic. The parasitism rate was highest in the marsh warblerAcrocephalus palustris(44.8%) followed by great reed warblerA. arundinaceus(33.8%), sedge warblerA. schoenobaenus(26.5%) and reed warblerA. scirpaceus(11.6%). Although the cuckoo eggs showed a high level of mimicry the eggs of the marsh warbler this host species rejected 72% of the cuckoo eggs, resulting in a cuckoo breeding success of only 4.3%. Cuckoo eggs laid in great reed warbler and reed warbler nests showed a similar hatching success, but the cuckoo chicks survived better in great reed warbler nests, resulting in a breeding success of 30.4%, as compared to 16.4% in nests of the reed warbler. The relationship between the level of parasitism, host rejection of cuckoo eggs, cuckoo chick survival and breeding success is discussed for the four host species.