(1892) Petrocles alchata caudacutus.
THE LARGE PIN-TAILED SAND-GROUSE.
Tetrao caudacutus Gmel., Reise de Buss., iii, p. 93 (1774) (N. Persia). Pteroclurus alchata. Blanf. & Oates, iv, p. 59.
Vernacular names. None recorded.
Description.— Adult male. Centre of crown and nape grey, tinged with ochre; chin and throat black; remainder of head rich orange or rufous-buff shading into ochreous on the neck all round; a black line from the eye to the back of the ear-coverts; back and scapulars olive-ochre, a few feathers of the back and most of the scapulars with a yellow subterminal spot and all margined with grey; lower back and rump yellow-buff barred with black ; upper tail-coverts more yellow and the bars on the longest arrow-shaped; tail barred blackish and buff at the base, becoming black and olive-ochre at the tip and the prolongations black; outer tail-feathers are tipped yellow and subtipped blackish ; wing-coverts white with black edges and broad bauds of chestnut-chocolate near the tips ; winglet, primary coverts and primaries grey, the last darker on the inner webs and edged with white ; outer web of first primary and all the shafts black; innermost secondaries like the scapulars ; secondary coverts yellow ochre with deep chocolate terminal bands ; breast pale pinkish-rufous, divided from the yellow of the neck and the white of the abdomen by narrow black bands; greater under wing-coverts grey; other under wing-coverts, axillaries and under tail-coverts white.
Colours of soft parts. Iris brown; bill dusky green to dull brown or shite-colour; feet dirty yellow to dusky green.
Measurements. Wing 213 to 224 mm.; tail 140 to 190 mm.: tarsus about 25 to 29 mm.; culmen 12.5 to 14.5 mm. Weight 10 to 12 oz.
Female. Upper parts from forehead to tail buff barred with black; interscapulars more rufous and tail-coverts more yellow; chin and throat white; rest of head like that of the male but pale and dull; wing-coverts white with black edges and rufous sub-terminal bars ; below the rufous of the neck there is a broad black collar, then a narrow ochre baud shading into grey and then another narrow band of black ; remaining under plumage as in the male.
Measurements. Wing 194 to 231 mm. Weight 8 1/4 to 11 1/4 oz.
Young males are barred above as in the female and acquire the adult plumage in patches.
First plumage.— Male and female. Whole upper parts, head, breast and neck dull buff barred with black or dark brown above and dull brown below; chin and throat white; wing-quills paler and freckled with reddish towards the tips.
Eclipse plumage similar to that of the female but without the dark bars on the back.
Nestling. Above reddish-brown, profusely spotted all over with black and with apical specks of white; white, black-edged lines on crown and sides of head from bill to the centre of the back and horse-shoe shaped on the mantle, two small similar horse-shoes on wings.
Distribution. Persia, Baluchistan, Afghanistan West to the South Russian Steppes, Asia Minor, Arabia and Northern Africa; South to the Sahara, Nubia and Abyssinia and India.
In the latter country it occurs in enormous numbers in the North-West Trans-Indus country and again between the Indus and Chenab; it is still frequently met with as far as the Gara and the Beas through the Punjab to Ludhiana and Delhi in the East; South it has been obtained as far as Sambhur, Jodhpur, Bikanir and Deesa.
Nidification. Pitman found this fine Sand-Grouse breeding in enormous numbers in Mesopotamia. During June and July he refers to one of the camps of the troops advancing on Kut-el-Amara as "-one huge breeding-ground," the birds not selecting the barest places like P. senegallus but making the scrapes for their eggs on places growing grass, thin vetch or the Polygonum, the seeds of which form their staple food. Vast multitudes breed in the same area, many nests being within a few yards of one another placed without regard to any special shelter. Many millions of pairs of birds must breed in the Tigris Valley, for day after day the troops were marching through breeding country in which the birds literally swarmed. They breed from early May to the middle of July but most eggs are laid during the last week of May and the first two weeks of June. Three eggs form the normal clutch but two only are often laid. They are the boldest and most richly marked of all Sand-Grouse eggs. In groundcolour they vary from a pale cream or yellowish-stone to a bright warm buff or salmon-pink. The primary markings consist of bold blotches and a few specks of vandyke-brown or deep red with light grey or neutral-tint secondary marks. These are numerous and generally all over the surface, in a few eggs being more numerous at the larger end. In shape they are nearly true ellipses. One hundred eggs average 45.0 x 30.4 mm.: maxima 49.9 x 29.9 and 40.1 x 33.3 mm.; minima 39.6 x 28.3 and 46.1 x 28.0 mm.
In India it certainly breeds in the Peshawar Valley and almost equally surely in the Quetta District. Bogle found it in pairs in the former district in June and a female shot by him contained an egg ready for expulsion.
When the young are hatched they are given drink by the male bird saturating his under plumage with water when drinking and then flying straight back to the nest, when the young suck the water from the soaked feathers.
Habits. For the most part at all events these Sand-Grouse are Winter visitors to India but they are resident over the greater part of their habitat, though making long local migrations or movements for the purpose of food or breeding. When rip© the seeds of a plant, Polygonum argyrocoleum, winch grows over an immense area in the Tigris and Euphrates valleys, forms the sole food of this Sand-Grouse and the birds resort to these places in myriads for breeding purposes, often coming great distances. Their young reared and the seeding of the Polygonum finished, the birds move elsewhere, again clear the ground of the special food available and then once more move off. During heavy rains and extreme droughts similar movements occur.
In India the birds are wild and afford splendid sport but in Mesopotamia Pitman and others speak of their being tame to foolishness and, though after a month's harrying they furnished splendid sport, they still refused to desert their favourite drinking-places. Their call has been described as " caa caa," rapidly and often repeated on the wing and as an angry " twoi twoi " when disturbed or frightened.
They run well and actively on the ground and swim lightly and elegantly on the water, looking like gulls in the distance.