a chirp, transcribed as , softer and more melodious than that of the house sparrow. It gives a flight call transcribed as twerp, and a song described by Russian naturalist V. N. Shnitnikov as "not loud, but pleasantly melodious with fairly diversified intonations". Taxonomy The saxaul sparrow was first described by English zoologist John Gould in a March 1872 instalment of The Birds of Asia, from a specimen collected near Kyzylorda, now in southern Kazakhstan, by Russian naturalist Nikolai Severtzov. Severtzov had been planning to describe the species as Passer ammodendri for several years and had been distributing specimens among other naturalists. When natural history dealer Charles Dode escaped from the Paris Commune in 1871 with some of his collection, Gould obtained specimens from a set of rare birds Dode exhibited to the Zoological Society of London. Severtzov did not describe the species until 1873, and some later writers preferred to attribute him, but Gould's description takes priority over Severtzov's. The saxaul sparrow's species name refers to its desert habitat, coming from the name of the Ammodendron or sand acacia tree, which is in turn derived from the Ancient Greek άμμος (ammos, "sand") and δένδρον (dendron, "tree"). The English name saxaul sparrow refers to the saxaul plant, with which it is closely associated. The saxaul sparrow usually is classified in the genus Passer with the house sparrow and around twenty other species, although a genus Ammopasser was created for the saxaul sparrow by Nikolai Zarudny in 1890. The saxaul sparrow's relations within the genus Passer are unclear, although with its black throat feathering it has usually been considered part of the "Palaearctic black-bibbed sparrow" group related to the house sparrow. J. Denis Summers-Smith considered that the Palaearctic Passer sparrows evolved about 25,000 to 15,000 years ago, during the last glacial period. During this time, sparrows would have been isolated in ice-free refugia, such as a certain steppe region in Central Asia, where Summers-Smith suggested the saxaul sparrow evolved. Genetic and fossil evidence suggest a much earlier origin for the Passer species, perhaps in the Miocene and Pliocene, as suggested by Luis Allende and colleagues in their 2001 phylogenetic analysis of mitochondrial DNA. This analysis also suggested that the saxaul sparrow may be an early offshoot or basal species in its genus, a relative of certain African sparrows such as the northern grey-headed sparrow. If the saxaul sparrow is related to