The Sudan golden sparrow (Passer luteus) is a small species of bird in the sparrow family found in sub-Saharan Africa. It is a famous cage bird, and in aviculture, it is known as the golden song sparrow. The Arabian golden sparrow and this species are sometimes considered one species, as the "golden sparrow". Taxonomy and systematics This species was first described by Martin Lichtenstein in 1823, as Fringilla lutea, from a specimen collected at Dongola, Sudan. Since then it has generally been placed in the genus Passer. The species name luteus means saffron yellow in Latin. The two golden sparrows are very similar, and have often been treated as the same species. Both are similar to the chestnut sparrow, and all three may once have been only clinally different. The male Arabian golden sparrow is almost entirely gold-coloured, the male chestnut sparrow is mostly chestnut, and the male Sudan golden sparrow is intermediate. British ornithologist Richard Meinertzhagen considered even the chestnut sparrow to be conspecific, though the range of the Sudan golden sparrow overlaps with that of the chestnut sparrow without any known interbreeding in a small area of Darfur. The three species are similar in their behaviour, which is adapted to the unpredictable conditions of their arid habitat. In particular, they and the Dead Sea sparrow share a courtship display in which males quiver 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 golden sparrows and chestnut sparrow 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, or a superspecies. 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, studies of sparrow mitochondrial DNA indicate that these species are either derived from or are the closest relatives of the Palaearctic black-bibbed sparrows. Description The Sudan golden sparrow is a smaller sparrow, at in length, with a wingspan of . Males are distinctive in their bright yellow head and underparts, deep chestnut brown wings and back, and two white wingbars. In