(1145) Riparia riparia diluta.
The Siberian SAND-MARTIN.
Cottle diluta Sharpe & Wyatt, Mori. Hirund., i, p. 65 (1893) (Taschent). Cotile riparia. Blanf. & Oates. ii, p. 272.
Vernacular names. Ababil Paki (Sind).
Description. Whole upper plumage smoky grey-brown, the tail and wing-quills darker; in fresh plumage there are pale edges to all the feathers, more conspicuously so on the lower back, rump and upper tail-coverts; lower plumage white with a broad band of smoky-grey across the upper breast; sides of neck, throat and flanks more or less suffused with smoky-grey; axillaries and under wing-coverts greyish-brown.
Colours of soft parts. Iris dark brown; bill black; legs and feet dark brown.
Measurements. Total length about 125 mm.; wing 96 to 108 mm.; tail 46 to 51 mm.; tarsus about 10 mm.; culmen about 6 mm.
Young birds are more boldly marked with pale rufous edges to their feathers and have the chin and throat fulvous.
Distribution. Breeding in Western Siberia and in Winter South to North-West India to Sind, Punjab and North-West Frontier Provinces. Osmaston saw Sand-Martins, probably of this race, in Ladakh during July at about 14,000 feet.
Nidification. It is possible this form breeds in Northern Xashmir and Ladakh but the material in the British Museum is so poor that it is impossible to decide this point. Eggs taken by Smirnoff in Minisinsk. on the 3rd June, are just like those of the Common Sand-Martin. The eggs of two clutches, one of four and one of six eggs, vary between 17.0 x 11.3 and 18.9 X12.7 mm.
Habits. Similar to those of the Common Sand-Martin. This race appears to be merely a Winter visitor to the plains of North-West India, arriving in late October and leaving at the end of March and early April. It is a common visitor to North-West India, South to Sind and the Bombay Presidency, East to the United Provinces and to Bihar, where it was obtained by Inglis.