(1147) Riparia riparia ijimae.
The Eastern Sand-Martin.
Clivicola r. ijimae Lonnb., J. Coll. Sci. Tokyo, xxiii, Art. 14, p. 38 (1908) (Sachalin). Cotile riparia. Blanf. & Oates, ii, p. 272 (part).
Vernacular names. None recorded.
Description. Similar to R. r. diluta but darker and with more conspicuous white, rather than sandy-grey, edgings to the feathers.
Colours of soft parts the same as in the other races.
Measurements. Wing 99 to 107 mm.; tail 49 to 52 mm.; tarsus about 12 mm.; culmen about 5 to 6 mm.
Distribution. Saghalin, Assam, Burma,Tibet, probably extending, throughout the North of China.
Nidification. Professor Ijima found large numbers of these little Swifts nesting on the cliffs along the shores of Saghalien. In Assam there were several breeding colonies, each of about 40 pairs, in Cachar, Sylhet and Dibrugarh. In two instances colonies of the Eastern Sand-Martin and the Indian Sand-Martin were breeding at the same time within a mile of one another, but in both cases each colony contained nothing but the one species and there was no interbreeding. Nests and eggs are indistinguishable from others of the genus. The few eggs in my collection vary in length between 14.9 and 18.5 mm., and in breadth between 11.8 and 12.1 mm. They possibly have two broods, as I found birds breeding in October and November and again in January and February.
Habits. Those of the genus. These little birds when not breeding roost in bushes and low trees where there are no reeds or elephant-grass but, where these hitter are available, always select them, occupying the same patch for weeks on end. They are very crepuscular and may be seen hawking insects over lakes and swamps until almost dark and again in the early morning they are among the first to wake and commence the daily quest for food. I once shot one of these Martins at Gunjong in N. Cachar at 2,500 feet, many miles from any water.