Brood parasitism by Horsfield's Bronze-Cuckoo in a fragmented agricultural landscape in Western Australia

Abstract

The avian brood parasite, Horsfield's Bronze-Cuckoo, Chrysococcyx basalis, showed evidence of area sensitivity in highly fragmented habitat in the central wheatbelt of Western Australia. Adult cuckoos were rarely recorded in small remnants and their breeding success depended on females finding a concentration of their host species in a single large remnant. Thus, the effects of habitat loss and fragmentation on the density and spatial distribution of their hosts would be expected to have an adverse outcome for this cuckoo and possibly also for other species of cuckoos in this area. Parasitism by Horsfield's Bronze-Cuckoos did not appear to have a negative effect on the persistence of their major host, the Blue-breasted Fairy-wren, Malurus pulcherrimus, in this area. Fairy-wrens bred successfully in the smaller remnants where parasitism was rare and the rate of parasitism varied considerably between seasons, being zero in some years.