their wings above their body. This intense display is probably an adaptation to nesting in a clump of trees surrounded by similar habitat, where such an intense display may serve important purposes in keeping a colony together. The chestnut and golden sparrows have been seen as highly primitive among the genus Passer, only distantly related to the house sparrow and the related "Palaearctic black-bibbed sparrows". In recognition of this they are sometimes placed in a separate genus or subgenus Auripasser. The courtship display of the Dead Sea sparrow was thought to have evolved separately in a similar environment from that of these species, in an example of convergent evolution. However, mitochondrial DNA phylogenies indicate that the chestnut and golden sparrows are either derived from or are the closest relatives of the Palaearctic black-bibbed sparrows. Description Like the other members of the sparrow family, the chestnut sparrow is a small, chunky songbird with a thick bill suited to its diet of seeds. At in length, it is the smallest member of the sparrow family. It weighs between and . Wing length ranges from in males and from in females. The tail, bill, and tarsus lengths are about , , and respectively. The plumage of the breeding male is mostly a deep shade of chestnut in colour with black colouration on the face, wings, and tail. The breeding male is not easily confused with any other birds except the chestnut weaver, which is substantially larger and has white on its wings. The breeding male's legs and feet are horn (pale grey) in colour. The non-breeding male chestnut sparrow has white flecking on the upperparts, and much of its plumage is buff or whitish with chestnut crescent markings, until the bright chestnut of the breeding plumage is exposed by wear. The non-breeding male's bill fades to a dusky-tipped horn, similar to that of females, but without dusky tones on the cutting edge of the mandible (lower portion of beak). Females have the same plumage pattern as males, though with somewhat duller colouration. The female has a grey head; buff supercilium, chin, and throat; black and warm brown upperparts; and off-white underparts. The bill of the female is pale yellow with the tip and cutting edge of mandible dusky. Juveniles are dull grey with a brown back, a pale yellow supercilium, and a pale horn bill. Females and juveniles have hints of chestnut on