884. Aeanthopneuste reguloides harterti

(884) Acanthopneuste reguloides harterti Stuart Baker.
THE KHASIA CROWNED WILLOW-WARBLER.
Acanthopneuste trochiloides harterti, Fauna B. I., Birds, 2nd ed. vol. ii, p. 481.
Acanthopneuste reguloides harterti, ibid. vol. viii, p. 642.
This race breeds in the hills South of the Brahmapootra in Assam and in Manipur. La Touche’s “disturbans” from Yunnan, is very close to this bird and may be the same.
Its nest has so far only been taken in the Khasia Hills by myself.
This Warbler, which keeps entirely to forest, was not uncommon in the Khasia Hills, between 4,500 and 6,200 feet. We found it both in Pine-woods and in evergreen wet forest but, in the former, it only haunted those places where there was a mixture of other trees and the detritus on the ground was of moss, dead leaves etc. I never saw the bird among Pine-trees standing alone, with the ground bare and dry except for its dense covering of Pine-needles. Three nests out of every four were placed on banks covered with moss, weeds and small bracken, while the fourth was built in a hole of some kind in a tree, dead or alive, or in a rotten stump. Of the nests built on banks, some were placed in holes among the roots of trees, some in hollows in the bank, and one or two in among the thick beds of moss and fern, the nest itself just flush with the growing moss and looking exactly like it. One nest I found built in among the moss growing on the thick, but stunted, bole of an Oak-tree, the nest resting partly on the stump of a broken bough and completely hidden by the surrounding moss. Some nests were very carefully hidden while others were not in any way concealed by covering growth, yet simulated so exactly the surrounding vegetation that they were very difficult to detect.
Each pair of birds seemed to have a wide range of hunting area quite to themselves. Nearly every wood with a mossy under¬growth had one or two pairs but in no wood under a mile long have I found more than three nests. If the woods were partly dry and partly damp and mossy, and one wanted to find the nests, the latter places had to be found first and then every area watched until a bird, or pair of birds, had been seen. After this it was only a case of waiting until the hen could be roused from the nest or the cock spotted as he paid her a visit. Sometimes, if the cock was very agitated and excited, showing we were too close to the nest to please him, the hen might be flushed off it by an examination of each likely mossy bank. Often, however, much patience and self-restraint would have to be practised before the cock would give any indication as to the whereabouts of the nest. Often, also, the hen would sit so close that my foot almost kicked the nest before she left it.
The nest is a much better-built affair than that of the Himalayan bird, unless observers have much maligned the latter. All those I have personally seen, about twenty or so, have been well built little balls of dark green moss, measuring between 4 and 5 inches either way. It is always made of quite tiny fragments of moss, seldom over a couple of inches long, these being welded and woven into very compact walls and roof. In some nests nothing but moss is used but, in others, a few small leaves, scraps of dead lichen, bracken or other oddments may be incorporated, perhaps by accident rather than design. The lining, normally, is a felted mass of the soft, white, downy seeds of grass or Cotton-tree, worked into a regular mat. In one nest I have seen an inner lining of soft white feathers and in one or two others just three or four tiny feathers worked in with the down. The mat of down, it should be noted, was nearly always worked into the moss of the base of the nest. One nest was fined entirely with black and red feathers of a Minivet and looked quite startling when pulled in half.
The breeding season lasts from the end of April to the beginning of June and I have found fresh eggs myself on the 11th of the latter month.
The eggs in a full complement number four or five and I have seen one six and two or three threes.
They are typical Acanthopneuste eggs in every way, pure white and of the usual shape and texture.
Fifty eggs average 15.3 x 11.9 mm. : maxima 17.0 x 11.6 and 16.1 x 13.0 mm. ; minima 13.6 x 10.9 mm.
The cock bird incubates for a short time morning and evening and, perhaps, during the night, as I have found the cock bird snared on the nest when visiting the latter at dawn. He never, however, incubates during the day. Both birds assist in the building of the nest but the female, probably, does most of the work.
This Warbler is cuckolded both by Cuculus saturatus and by Guculus polycephalus and is, therefore, intensively worked for by my trained Cuckoo men, and this may have made me consider the bird to be more common than it is. The Cuckoo’s egg, whichever of the two species it may belong to, is placed in the nest without the latter being damaged in any way, though tw0 seen by myself had the top rather pressed in, as if the Cuckoo had settled on it in putting the egg in.