(488) Heteroxenicus cruralis (Blyth).
THE WHITE-BROWED SHORT-WING.
Heteroxenicus cruralis, Fauna B. I., Birds, 2nd ed. vol. ii, p. 17.
This Short-wing breeds from Sikkim to Eastern and Southern Assam and thence into the Chin and Kachin Hills to Karenni. In Sikkim it breeds at all heights from 5,000 feet to 10,000 feet, at which height Stevens shot a breeding pair ; in Assam they breed from 5,000 feet up to 9,000 ; in the Chin and Kachin Hills apparently from 6,000 feet upwards ; whilst in Karenni they probably only breed in a few places on the highest ridges.
It keeps almost entirely to forest or thick brushwood at all seasons and prefers such, even of these, which are green, wet and mossy, with plentiful rocks and boulders breaking up the undergrowth.
The first nest ever taken of this bird contained an egg of Cuculus poliocephalus in it under two of the foster parent. This nest was taken by a Mr. F. Gleadow at an elevation of about 9,500 feet in the Tons Valley and given to Osmaston, who at the time did not know what the nest was. “The nest was cup-shaped, made of moss and lined with thin black fern-stalks. It was placed up against a low rock and concealed by a bunch of ferns growing out of the same” (Journ. Bomb. Nat. Hist. Soc. vol. xi, p. 471, 1898.)
In 1903 Osmaston took seven nests round Darjiling, and from them was able to indentify the above. Of these nests he writes (ibid. vol. xv, p. 511, 1898) :—“ The bird is not uncommon in the dense mossy forests from 6,000 to 8,000 feet. It has a pretty short song of a few notes which, however, ends up harshly.
“I found seven nests of this species this year between 15th June and 15th July. They were all domed structures composed entirely
of moss and lined with fine roots, with a large opening, about 2" to 2.1/2" across, on one side.
“They were all built up against the face of a moss-covered vertical rock or tree-trunk, the nest being so neatly incorporated into the mossy covering of the rock or tree that it was almost impossible to say where the nest began and where it ended. The entrance to the nest is often parallel to the face of the rock or tree and is so artfully concealed that the presence of a nest is rarely suspected until betrayed by the exit of the parent bird.
“The full complement of eggs is three, though only two are some¬times laid.
“They are long ovals, pure white, with a slight gloss.
“The mean of the measurements of 15 eggs gave .90" x .64".”
In the Khasia Hills they breed earlier than in Sikkim, for I found eggs from the middle of May to the middle of June on some of the highest ridges, 5,000 to 6,200 feet, making a similar domed nest of moss to that described by Osmaston.
They were all found in very damp shady forest of Oak and Rhododendron, growing very densely, with a thick green under¬growth of bracken, ferns and bushes. Everywhere there were many orchids and long streamers of vivid green moss growing all over the trunks of trees and on the great rocks which showed their heads in numbers above the bushes. The nests were woven into these masses of green moss, the entrance in most cases being between the nest and the face of the rock or tree and the nest itself looking like a bulge in the moss surrounding it. The bird was rare and we never found more than two nests in a season and often none at all.
The eggs are as described by Osmaston, pure white, with a fine satiny texture and a slight gloss. In shape they are rather long ovals, with the smaller end often slightly pointed. A few eggs are rather broader.
Thirty-one eggs, including Osmaston’s, most of which are now in my collection, average 22.7 x 16.0 mm. : maxima 23.2 x 15.6 and 23.1 x 16.5 mm. ; minima 19.8 x 14.3 and 20.1 x 14.1 mm.
As already stated, the season in Assam for laying is May and early June, and in Sikkim, at all events at the higher elevations, between early June and late July.
The male bird, as with so many others of the Short-wing Chats, seems to breed as often in the immature as in the mature plumage and, it may be, that some males never acquire this in the Eastern portion of their range.
488. Heteroxenicus cruralis
(488) Heteroxenicus cruralis (Blyth).