The Spanish Sparrow Passer hispaniolensis, also sometimes called the Willow Sparrow, is a species of sparrow closely related to the House Sparrow. It has a complex distribution in the Mediterranean region in Cape Verde, the Canary Islands, Madeira, northern Africa, western Spain, Sardinia, Sicily, Malta, the Balkans, and across southwest and central Asia from Turkey east to westernmost China. It is however absent from some parts of the Mediterranean region, notably Italy and Corsica, where it is replaced by the Italian Sparrow, a sparrow intermediate (and possibly hybrid) between Spanish Sparrow and House Sparrow. It also hybridises freely with House Sparrow in parts of northern Africa (northeastern Algeria, Tunisia, and northwestern Libya), forming highly variable mixed populations with a full range of characters from pure House Sparrows to pure Spanish Sparrows and everything between.
The range expanded greatly over the last 200 years, partly through natural colonisation, as in the Balkans (Bulgaria, Romania, Serbia, and Moldova colonised from 1950 onward), and partly through accidental human intervention, with the species reaching the Canary Islands (early 19th Century) and Cape Verde (1832) on board ships. Madeira was colonised in May 1935 after a period of severe east winds blew some birds in. It is mainly resident in the west of its range, but eastern populations are more migratory; birds from the Balkans and Turkey migrate to northeast Africa and the Arabian Peninsula. Odd birds have wandered as far north as Scotland and Norway.
It is 15-16 cm long and weighs 22-36 g, slightly larger and heavier than House Sparrows, and also has a slightly longer and stouter bill. The male is similar to the House Sparrow in plumage, but has a red-brown (not grey) crown, white (not pale grey) cheeks, blacker back, and underparts heavily streaked with black. The female is effectively inseparable from House Sparrow on plumage, only distinguishable by its slightly heavier build.
It is an urban bird in some areas, notably where House Sparrows are absent such as the Canary Islands, Madeira, and Malta, but more often breeds in trees near rivers or other wet areas in farmland well away from buildings. Like other sparrows this species feeds principally on seeds. It is strongly gregarious, often building closely spaced or even multiple shared nests, though each pair having an individual nest cavity and entrance; some colonies breed in the base of large nests of birds like White Storks. Colonies may hold anything from a few pairs up to over a thousand pairs. Each pair lays 3-8 eggs, which hatch in 12 days, with the chicks fledging when about 14 days old.