Saxaul Sparrow - Behaviour

Behaviour

Little is known of the Saxaul Sparrow's behaviour, because of its remote range. It is shy in many areas, and spends much time hidden in foliage, but breeding birds in Mongolia were reported to be "quite confiding". When not breeding, it is social, and can form flocks of up to fifty birds, sometimes associating with Eurasian Tree, Spanish, and House Sparrows. In some regions, it makes small local migrations. Towards the spring, Saxaul Sparrows form pairs within their flock, before dispersing in April. Seeds, especially those of the saxaul, are most of its diet, though it also eats insects, especially while breeding, most commonly weevils, grasshoppers, and caterpillars. It forages in trees and on the ground. In a study of insects fed to nestlings in the Ili River valley, it was found that beetles are predominant, with weevils and Coccinellidae comprising 60 and 30 percent of the diet of nestlings, respectively. Because of its desert habitat and scarcity, it is not a pest of agriculture. Where water is not available, the Saxaul Sparrow may fly several times each day over long distances to drink.

The Saxaul Sparrow is less social than other sparrows while breeding, due to its dry habitat and its choices of nesting locations, holes in trees and earth banks. Isolated pairs are usual, though it sometimes breeds in small groups, with members of its own species as well as House and Eurasian Tree Sparrows. The breeding season is short, lasting from May to July, with most young raised in April and June. Unusually for a sparrow, it has not been recorded nesting openly in branches, though this may simply represent the lack of published records. Nests are often built in tree cavities, where they are sometimes placed close together. Other common nesting localities are earth banks and rocky slopes, and nests have been recorded on the nests of birds of prey, unused buildings, walls, and electricity pylons. Nests in man-made structures are increasingly common, as large trees in the Saxaul Sparrow's habitat are removed. Nests may be quite close to the ground, especially when they are built in trees.

The Saxaul Sparrow's nests are untidy dome-shaped constructions, with an entrance in the side or top. They are built of grasses, roots, and other plant materials, and are lined with feathers, fur, and soft plant material. The nest is mainly built by the female, though the male may actively take part in building. Typical clutches have five or six eggs, and two clutches a year are normal. Eggs are broad and ovular, slightly pointed at an end. They are glossy, coloured white and shaded with rusty grey or yellowish brown. In some clutches, one egg is noticeably paler than the others. Four eggs collected by Zarudny from Transcaspia had an average size of 1.9 × 1.4 cm (0.75 × 0.57 in). Females play the main part in incubating eggs, and males can often be seen guarding the nests during incubation. Males and females share in feeding their young, which they do every 4 to 12 minutes. Young that have left their nest remain nearby until well after their moult, before departing for winter flocks, followed later by the adults.