Riparia riparia - Sand Martin
Feather characters. Barbules are extremely short (0.45-0.49 mm) and divided into pigmented nodes and partly pigmented (less than 50%) internodes. Bell-shaped nodes are equally distributed along the proximal part of the barbules (36-44 per mm). Depending on the feather type, nodes gradually or abruptly decrease in size towards the distal end until only slightly thickened. Villi are rounded and internodes are straight. Prongs are absent. Barbules have this typical structure for Passeriformes; pigmented, bell-shaped nodes combined with rounded villi.
Field characters. Size 12 cm. Weight 14.6 g (12.0-18.6) (Dunning, 1993). Smallest swallow, easily identified by white underparts with brown breastband, white throat, dark underwings and much shallow forked tail. Smaller than Barn Swallow with much shallower forked tail; separable from House Martin by lack of white rump and by brown upperparts, not shiny black and bluish. Flight weaker than Barn Swallow. Often in large flocks, especially near colonies, but also seen in singles during migration. Outside breeding season, roosts in flocks on electricity wires, branches, etc.
Voice. Call 'drrr' or 'chrrt', drier and more buzzing than call of House Martin. Song chittering and buzzing, like a series of calls.
Distribution. Summer visitor. Widespread and common, but decreasing in many parts of region due to habitat destruction. Map: see MapIt.
Habitat. Breeds in self-constructed holes in sandy and loamy river banks and on other places with vertical banks like gravel pits. Usually avoids mountainous areas.
Food. Invertebrates, taken on wing only. Feeds in lower airspace.