A GREAT-REED X REED WARBLER (ACROCEPHALUS -ARUNDINACEUS X ACROCEPHALUS-SCIRPACEUS) HYBRID AND ITS PARENTAGE

A medium sized Acrocephalus Warbler which initially could not be ident ified was captured in Bavaria in June 1995. The bird held a territory between two Great Reed Warbler males and responded to playback of Grea t Reed Warbler song. Using PCR with microsatellite primers sequence th e bird could be identified as a Great Reed x Reed Warbler hybrid (Fig. 1). Based on mt DNA sequence analysis the hybrid's mother was a Great Reed Warbler (Fig. 2). With respect to the hybridization process the main difference between the parental species occur in body size (Great Reed Warbler being 2.7 times larger than Reed Warbler) and mating sys tems. Whether the hybrid resulted from an extra-pair copulation or a m ixed pairing is unknown. External morphology of the hybrid was interme diate between the parental species (Tab). The bird sang a mixed song i ncorporating both parent species' songs (predominantly Great Reed Warb ler) as well as intermediate songs into its own (Fig. 3).