publication in press
Abstract
The Giant Cowbird (Molothrus oryzivorus) is an obligate brood parasite whose historically recognized hosts were dominated by colonial, pendulous-nesting icterids. Subsequent records have expanded its host spectrum and now do include solitary territorial and cooperative-breeding species. This report increases the documented host spectrum of Giant Cowbird and expands its known range of exploited breeding systems by a territorial, pair-breeding host with a solitary open-cup nest. An observation is described and evidence provided of a juvenile Giant Cowbird repeatedly soliciting and receiving food from an adult Scrub Blackbird (Dives warczewiczi). The repeated observations provide strong behavioural evidence of post-fledging parental care and host use. Scrub Blackbird therefore represents a previously unrecorded host species and the first host record for the genus Dives.
