Variation in Size and Shape in Pigeons, Columba Livia

AnsraAcT.-Morphometric studies of Rock Doves and feral pigeons (Columba livia) are enhanced by knowing that variation in size and shape has a well-studied genetic causation in domestic pigeons. Size distributions of skeletal elements of the sexes approximate normality; males are significantly larger than females. Size as measured by principal component I of feral females shows significant interlocality variation, and tends to increase with latitude in North America. Size of males shows no such geographic patterning. Relative limb lengths vary inversely with core size in feral pigeons. Large pigeons have proportionately shorter wings, heavier wing-loading, and are likely to fly faster than small ones. This may explain why homing pigeons tend to be larger than feral pigeons, which are more like wild Rock Doves than homers. Since feral colonies could be colonized by domestics of all sizes, the absence of very small and very large birds probably reflects results of interbreeding of colonizers with resident ferals, and ultimately natural selection for intermediate sizes. Received 24 April 1989, accepted 26 Aug. 1989.