Geographical isolation and morphological and habitat differentiation between birds of the Kimberley and the Northern Territory

Abstract

Geographical barriers in the area of the Joseph Bonaparte Gulf, Victoria River and Daly River, have isolated populations of some birds in the Northern Territory from their vicariants in the Kimberley, Western Australia, thus allowing morphological divergence between them. These birds are adapted to wet-country habitats, sandstone ranges and tropical savanna woodland. Several stages of speciation are evident. At least four isolates in the Kimberley occupy different types of habitats compared with their vicariants in the Northern Territory.