Willow sparrow
The Spanish sparrow or willow sparrow (Passer hispaniolensis ) is a passerine bird of the sparrow family Passeridae. It is found in the Mediterranean region and south-west and central Asia. It is very similar to the closely related house sparrow, and the two species show their close relation in a "biological mix-up" of hybridisation in the Mediterranean region, which complicates the taxonomy of this species.
The Spanish sparrow is a rather large sparrow, at 15–16 cm (6–6.5 in) in length, and 22–36 g (0.78–1.27 oz) in weight. It is 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 differs in that its underparts are heavily streaked with black, has a chestnut rather than grey crown, and has white rather than grey cheeks. The female is effectively inseparable from the house sparrow in its basic plumage, which is grey-brown overall but more boldly marked. The female has light streaking on its sides, a pale cream supercilium, and broad cream streaks on its back.
Two subspecies of the Spanish sparrow – the western Spanish sparrow (P. h. hispaniolensis ) and eastern Spanish sparrow (P. h. transcaspicus ) – are recognised, with little visible difference between them in worn breeding plumage. They are more easily distinguished in fresh winter plumage, with the eastern subspecies P. h. transcaspicus being paler with less chestnut.
The Spanish sparrow has a highly complex distribution in the Mediterranean region, Macaronesia, and southwest to central Asia. It breeds mostly in a band of latitude about 15 degrees wide, from the Danube Valley and the Aral Sea in the north to Libya and central Iran in the south. Its range has expanded greatly by natural colonisation over the last two centuries, in the Balkans, where it reached Romania, Serbia, and Moldova from 1950 onwards; and in Macaronesia, where its range expansion has been attributed to introductions and travel by ship, but was more likely natural colonisation by migrating birds. Vagrants occur widely, as far north as Scotland and Norway.
A study has shown that vagrant individuals tend to occur very close to railway lines, much closer than with other vagrant passerines. This results suggests that Spanish sparrows' vagrancy and expansion may be facilitated in part by cargo trains.
In most of its range, the Spanish sparrow occurs alongside the house sparrow. In such areas, both species breed in farmland and open woodland, with the Spanish sparrow preferring moister habitats. In areas where house sparrows are absent, the Spanish sparrow may live in urban habitats, as in the Canary Islands, Madeira, and some Mediterranean islands. In a few urban areas, such as those in eastern Sardinia, the primary sparrow species is the Eurasian tree sparrow. Before the Spanish sparrow arrived in the Canary Islands and Madeira, the rock sparrow was the sole native sparrow. In the Canaries, the Spanish sparrow occurs in most habitats, having ousted the rock sparrow from all but the driest localities. In Madeira the Spanish sparrow is common in cultivated areas, but it has not fully adapted to nesting in buildings or breeding in the drier north of the island. The Spanish sparrow is not common on most of the Cape Verde islands, due to the presence of the endemic Iago sparrow, and the house sparrow on São Vicente. On Fogo, where it is the sole species of sparrow, it is common in all habitats, breeding both in the houses of São Filipe and on the cliff walls of the volcano Pico do Fogo.
The Spanish sparrow is strongly gregarious, flocking and breeding in groups. In the winter, it mostly wanders nomadically or makes regular migrations.
Little is known of the Spanish sparrow's survival rate, and the maximum age recorded is 11 years.
Like other sparrows, it feeds principally on the seeds of grains and other grasses, also eating leaves, fruits, and other plant materials. Young birds are fed mostly on insects, and adults also feed on insects and other animals during and before the breeding season. Nestlings are fed almost exclusively on insects for their first few days, and are gradually fed larger amounts of grains. The portion of insects in nestling diets is recorded at a range from 75 to over 90 percent. In preying on insects, the Spanish sparrow is opportunistic, feeding on whichever insects are most common. In Central Asia, these are caterpillars, ants, grasshoppers, and crickets. While migrating through Central Asia in the spring, the Spanish sparrow feeds mostly on crops in cultivated areas, and while breeding it feeds mostly on insects, wild plants, and seeds from the previous year.
The Spanish sparrow nests in large colonies of closely spaced or even multiple shared nests. Nests are usually placed in trees or bushes, amongst branches or underneath the nests of larger birds such as white storks. Colonies may hold from ten pairs to hundreds of thousands of pairs. Each pair lays 3–8 eggs, which hatch in 12 days, with the chicks fledging when about 14 days old. Males spend more time constructing nests than females.
The European population of the Spanish sparrow comprises between 2,800,000 and 6,200,000 breeding pairs or 8,400,000–18,600,000 individuals. Partly from the European population, the global population is estimated to be between 17 and 74 million individuals. There have been population decreases in some parts of Europe, but in other areas the population has increased and the species is not seriously threatened, so it is assessed as least concern on the IUCN Red List.
