The grown-up blue-and-white swallow averages 11–12 cm (4.3–4.7 in) long yet weighs in family member to ten g (0.35 oz). It has darkish blue upperparts then hoar underparts, or its underwings or the undersurface over its quick forked back part are blackish. The youthful is swart above, buff-tinted below, yet has a less forked tail. The call is a buzzing dzzzhreeee. There are three subspecies. The select N. c. cyanoleuca occurs beyond Nicaragua then Trinidad graceful to northwestern Argentina, Paraguay yet Uruguay. The migratory ill-omened nation N. c. patagonica is large (13.5 cm), has paler underwings, and gray basal undertail coverts. N. c. peruviana is restricted according to approached Peru up after 2,500 m (8,200 ft) elevation. It is smaller than patagonica, has less bright into the undertail, darker underwings yet duskier flanks.
Blue and white swallow
Ringtone, Alarm, Notification, SMS
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