(512) Aenanthe isabellina.
The Isabelline Chat.
Saxicola isabellina Cretzschm., Atlas zu Rupp. Reise, Vog. p. 52 (1826) (Nubia); Blanf. & Oates, ii, p. 77.
Vernacular names. None recorded.
Description.— Male in summer. Head to back and scapulars sandy-brown; warmer and slightly buff on lower back and scapulars; longest feathers of the rump and upper tail-coverts white; middle pair of tail-feathers white at the base for about one-third of their length, black on .the terminal two-thirds; lateral feathers white on two-thirds of their length, black on one-third only, all narrowly edged and tipped with white or pale fawn; wings dark brown, each feather narrowly edged with fulvous; a narrow white supercilium from the nostrils to the ear-coverts; a line through the eye dark brown or black; ear-coverts fulvous, the colour extending down the sides of the neck ; chin and centre of throat whitish; rest of lower plumage buff albescent on centre of abdomen, warmer and more fulvous on breast and flanks.
In winter the edges to all the feathers are broader and affect the general colour to a greater extent.
Colours of soft parts. Iris deep brown; bill, legs and feet black.
Measurements. Total length about 180 mm.; wing 96 to 100 mm.; tail 53 to 56 mm.; tarsus 30 to 31 mm.; culmen about 15 mm.
Female like the male, but has the lores duller brown and the supercilium sometimes less distinct.
Distribution. Breeding from the South Russian Steppes, Asia Minor, Palestine, Afghanistan, Baluchistan, Persia and Tibet to East Siberia and N.W. China. It breeds in British Baluchistan, N.E. Kashmir and in Ladak, and winters in the plains of North-West India.
Nidification. The Isabelline Chat breeds within our limits practically all along the Baluchistan and Afghanistan frontiers. Betham and Marshall found many nests round about Quetta, and Rattray obtained others near Thull at about 4,500 feet. The nests taken by Betham and Marshall were all in rat-holes in the ground, and the former describes the nest as " composed of wool, hair, roots, feathers, cotton, coir, rags, or any other soft material avail¬able ; a conglomerate mass with a depression in the centre in which the eggs were deposited. Often toads and beetles share the burrow with the birds, though they may not occupy the nest-chamber itself." Rattray found the nest in holes under stones.
The eggs are four or five in number, and are generally a very pale spotless blue in colour, occasionally there are a few pale freckles at the larger end. In shape they are broad, rather blunt ovals.
Seventy-five eggs (Hartert 55) average 21.9 x 16.4 mm. Indian eggs are rather small, averaging only 21.3 x l6.l mm.: maxima 25.1 X 17.3 mm.; minima 19.5 x 15.6 and 20.0 x 15.2 mm. The breeding-season is from the beginning of April to the middle of June.
Betham notes that " during the breeding-season the male makes himself very conspicuous by bis quaint antics. He jumps up into the air, uttering a curious guttural note, and floats through it, with his tail spread and his rump arched showing up spotlessly white against the black. He gradually ascends some thirty or forty feet and then descends slantwise to the ground, but always on to some raised mound, never on to the flat ground."
Habits. Those of the genus. Buxton remarks on its partiality for salt desert with scanty vegetation, which it shares with Sylvia nana.