(2153) Crocethia alba.
Trynga alba Pallas. Vroeg's Cat. Coll. Adum.,p. 7 (1864) (Holland). Calidris arenaria. Blanf. & Oates. iv, p. 279.
Vernacular names. None recorded.
Description. - Breeding plumage. Upper parts rufous, each feather with a broad black centre and narrow white fringes ; lateral rump-feathers and upper tail-coverts white; central tail-feathers blackish, narrowly tipped with white and paler on the inner webs, lateral feathers grey-brown edged with white; primaries black with white shafts and with pale inner webs becoming white, extending to the outer webs on the innermost primaries; outer secondaries grey with white edges ; greater coverts brown with broad white tips ; inner coverts like the back; chin, throat, fore-neck and upper breast rufous spotted with black ; remaining under plumage, axillaries and under wing-coverts white, the rufous with black spots sometimes extending down the flanks.
Colours of soft parts. Iris dark brown ; bill black; legs and feet, dusky-grey or brown to black.
Measurements. Wing 118 to 129 mm.; tail 52 to 62 mm.; tarsus 23 to 26 mm. (once 21 mm. only); culmen about 21 to 26, once 28 mm.
In Winter the upper plumage is black with broad white edges, giving the impression of greyness ; the hind-neck is generally grey, the dark centres obsolete ; forehead and face white, but generally some rufous and black markings on the lores; lower back, rump and upper tail-coverts grey, the back' and rump with tiny black bars, the coverts with pale whitish tips and blackish sub-tips merging into the grey of the base; wing-coverts and innermost secondaries like the back; quills as in the Summer plumage ; lower plumage all white.
Distribution. Cosmopolitan, breeding in the Artie regions and migrating South in Winter over all the Southern continents. In India it is a common visitor to the North-West, extending South to the Maldives and the Malabar coast (one); East it is found scattered here and there throughout Eastern India and Burma, though very rare. It occurs also on Christmas Island, Henderson Island and more frequently in Borneo.
Nidification. The breeding of the Sanderling is so far North that but little has been recorded. It lays from the end of June to the middle or end of July, laying the normal four eggs in a scraping in the soil of the tundras, generally selecting a rather bare, stony patch. In colour the eggs have a rather dull greenish ground, becoming more buff if kept for long, spotted and speckled rather sparsely with reddish-brown and ashy-grey. The average of forty-one eggs (Jourdain) is given as 35.7x 24.7 mm.: maxima 38.2 x 24.7 and 34.1 x 26.1 mm.; minima 33.1 x 24.4 and 35.3 x 23.5 mm. Both male and female take a share in incubation.
Habits. Very much the same as those of other small Waders, with which, in India, it is generally found consorting in small flocks, running about on sand and mud-flats, feeding on all kinds of small mollusca, insects, worms etc.