Physical characteristics

The sparrows, with their short, robust bills, have specialized in the seeds of grasses, particularly the cultivated cereals that have been developed from them. Their tongues have a unique skeletal structure that plays a part in dehusking the seeds. These birds are also distinguished by a complete post-juvenile moult. The bills of the males change from horn to black when they become sexually active. Most are comparatively sedentary. The true sparrows and the rock sparrows have short, blunt wings and are not strong fliers, making short, direct flights. The snow finches and the ground sparrows, living in more open country, have proportionately longer wings with varying amounts of white in their plumage that show prominently in the display flights that are characteristic of open-country birds. The sexes in the snow finches, ground sparrows, and rock sparrows are basically alike, the latter being distinguished by a yellow spot on the throat. In contrast, most of the true sparrows are dimorphic with the males characterized by black bibs and well developed head patterns.

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