![]() The male helps, but can only cover the eggs rather than truly incubate them. She develops a brood patch of bare skin and plays the main part in incubating the eggs which lasts for 11-14 days. The female lays 4 or 5 white, bluish-white, or greenish-white eggs, spotted with brown or grey. House sparrows sometimes excavate their own nests in sandy banks or rotten branches, but more frequently use the nests of other birds in banks and cliffs, and old tree cavity nests. Holes in cliffs and banks, or tree hollows, are also used. Their nests are most frequently built in the eaves and other crevices of houses. House sparrows breed in colonies and generally produce 2 broods per year. When a female approaches a male during this period, the male displays by moving up and down while drooping and shivering his wings, pushing up his head, raising and spreading his tail, and showing his bib. Unmated males start nest construction and call particularly frequently to attract females. Males take up nesting sites before the breeding season, by frequently calling beside them. Many birds do not find a nest and a mate, and instead may serve as helpers around the nest for mated pairs this role also increases the chances of being chosen to replace a lost mate. House sparrows are monogamous and typically mate for life. This call is also used by females in the breeding season, to establish dominance over males while displacing them to feed young or incubate eggs. Aggressive males give a trilled version of their call, transcribed as 'chur-chur-r-r-it-it-it-it'. Much communal chirping occurs before and after the birds settle in the roost in the evening, as well as before the birds leave the roost in the morning. Most of their vocalizations are variations of their short chirping call that may sound like 'chirrup', 'tschilp', or 'philip' this note is made as a contact call by flocking or resting birds, or by males to proclaim nest ownership and invite pairing. Some young birds disperse long distances, especially on coasts, and mountain birds move to lower elevations in winter. However, limited migration occurs in all regions. Most House sparrows do not move more than a few kilometers during their lifetimes. On the ground, House sparrows typically hop rather than walk they can also swim when forced to do so by pursuit from predators. At feeding stations and nests, females are dominant despite their smaller size, and they can fight over males in the breeding season. These little birds feed mostly on the ground, but they flock in trees and bushes. House sparrows also engage in social activities such as dust or water bathing and "social singing", in which birds call together in bushes. They roost communally and while breeding nests are usually grouped together in clumps. They are gregarious during all seasons when feeding, often forming flocks with other species of birds. The bills of young birds are light yellow to straw, paler than the female's bill. Juvenile males tend to have darker throats and white postoculars like adult males, while juvenile females tend to have white throats. Juveniles are similar to adult female, but deeper brown below and paler above, with paler and less defined supercilia. The female's bill is brownish-grey and becomes darker in breeding plumage approaching the black of the male's bill. ![]() Its upperparts and head are brown with darker streaks around the mantle and a distinct pale supercilium. The female has no black markings or grey crowns. The male's bill is dark grey, but black in the breeding season. Wear and preening expose many of the bright brown and black markings, including most of the black throat and chest patch, called the "bib" or "badge". The male is duller in fresh nonbreeding plumage, with whitish tips on many feathers. The upper back and mantle are a warm brown, with broad black streaks, while the lower back, rump, and upper tail coverts are greyish brown. The underparts are pale grey or white, as are the cheeks, ear coverts, and stripes at the base of the head. ![]() It has a small white stripe between the lores and crown and small white spots immediately behind the eyes (postoculars), with black patches below and above them. It has black around its bill, on its throat, and on the spaces between its bill and eyes (lores). The male has a dark grey crown from the top of its bill to its back, and chestnut brown flanking its crown on the sides of its head. The sexes exhibit strong dimorphism: the female is mostly buffish above and below, while the male has boldly colored head markings, a reddish back, and grey underparts. The plumage of the House sparrow is mostly different shades of grey and brown.
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