A WELL DEVELOPED SINGLE CECUM IN THE COMMON BRONZEWING (PHAPS-CHALCOPTERA) AND THE SPINIFEX PIGEON (GEOPHAPS-PLUMIFERA)

Most groups of birds have paired (left and right) ceca opening into th e cranial part of the rectum. Ceca are absent in a number of birds, e. g. Psittaciformes and some Columbidae (e.g. Baumel 1979, Landolt 1984) . A single cecum (typical for almost all mammals) is only found in cer tain birds, notably known up to now in some spp. of Procellariiformes, Ciconiiformes (especially herons), and Pelecaniformes (Clench & Mathi as 1995). We dissected two different Columbidae-species (freshly kille d and then lost by an Australian Hobby Falco longipennis) in Karijini NP, Western Australia, in November 1996. They both showed an unpaired cecum. in Phaps chalcoptera the cecum reached a length of at least 45 cm (length of total alimentary tract: 45 cm). The one of Geophaps plum ifera was about 4 cm in length (total alimentary tract: 39 cm). These relatively big ceca may be related to food availability.