(280) Stachyridopsis rufifrons ambigua Harington.
THE ASSAM RED-FRONTED BABBLER.
Stachyridopsis rufifrons ambigua, Fauna B. I., Birds, 2nd ed. vol. i, p. 270.
The Assam Red-fronted Babbler is found from Sikkim to the extreme East of Assam, both North and South of the Brahma¬pootra, and Manipur. In Sikkim it appears to keep to elevations under 3,000 feet even in the breeding season, but I have no record thence of its nesting. It occurs all along the foot-hills, and Stevens records it from many places at the edge of the plains in Lakhimpur. Coltart and I obtained it breeding near Margherita, but it was very rare there. South of the Brahmapootra it was very common in the foot-hills, adjacent plains and up to 2,000 feet, though it bred in small numbers up to 3,000 feet in the valleys between much higher hills.
Like the Red-headed Babbler, these birds may be found in almost any kind of jungle or forest, though I never once saw them in Pine forest, perhaps because these grew mostly at a higher elevation than this species frequents. On the whole it is less often seen in green, humid forest than it is in bamboo-jungle, scrub and bush, or in deserted clearings. These last are certainly its favourite resort, especially for breeding purposes. The clearings are made for cultivation in dense forest, the trees are cut down, only the largest being merely ringed and left standing ; then, when the jungle has withered and dried, it is set fire to and burnt off. After cultivation of rice for a few years the clearing is abandoned and at once shrub-growth and weeds spring up ; in the second year clumps of small bamboos appear, and in the third year there is a dense matted jungle of bamboos, bush and small trees in which the Red-fronted Babblers, with many other birds, can nest and slink about with but little chance of interference.
H. A. Hole found this bird breeding in Sylhet in the numerous bush-covered ravines which debouched from the forest into the plains along the foot-hills ; whilst Stevens records their haunting similar ground in Lakhimpur.
The nests are not often placed actually on the ground, though I have seen a few in this position, generally on banks in rather thin bamboo-jungle in which there was not much undergrowth but where it was carpeted with a deep bed of fallen bamboo-leaves. Most of my nests have been taken from bamboo-clumps ; some from inside the clumps, resting on the rubbish collected there, more from the outside of the bamboos, where they were generally wedged in between the masses of little twigs springing from the lower nodes of the bamboos. In three instances out of four they would be placed between 18 inches and 3 feet from the ground but I have seen nests as high as 6 or 7 feet up.
The nests are typical of the genus but, considering the materials of which they are made, better put together and more compact than the others. The ordinary nest is domed, placed upright in between supporting twigs or on a bed of leaves and rubbish inside a clump. A few nests are deep cups or semi-domed, and I have taken several which were like big eggs, the smaller end having been sliced off on a slant. These generally stood a little on one side, whilst the materials were slightly drawn in at the small end to reduce the size of the entrance. The materials used are principally bamboo-leaves, but mixed with these are grasses and leaves, whilst some nests are almost completely made of grass alone, this being well interlaced and forming quite a stout little nest. The lining in most cases is of fine fibrous roots and is quite well and compactly made. At times, however, the lining is dispensed with, or consists merely of a few roots or fibres placed anyhow at the bottom of the nest. Domed nests measure from 5 to 7 inches outside if made of bamboos but, if made of grass only, some 4.1/2 to 5.1/2 inches. The cup is always a neat little affair about 2 inches in diameter by about 1.1/2 in depth.
The breeding season is May and June, but a few birds breed in July and a good many in April.
The usual clutch is four eggs, and I have taken one or two of five and a good many incubated sets of three.
The eggs certainly could not be distinguished from those of the Red-headed Babbler and, unfortunately, the birds also certainly cannot be distinguished at a cursory glimpse, so, as their breeding areas overlap, one has always to snare a bird on the nest in order to make certain of its identity. Although shy little birds, they sit very close and, if disturbed from the nest, soon return to it. Both sexes take part in incubation, for I have trapped both sitting on their eggs.
One hundred eggs average 16.1 x 12.4 mm. : maxima 17.3 x 12.8 and 15.5 x 13.2 mm. ; minima 14.8 x 11.9 mm.
In shape the eggs are broad ovals, the texture close and fine and the surface with a moderate gloss. The shell is stout for so small an egg.
280. Stachyridopsis rufifrons ambigua
(280) Stachyridopsis rufifrons ambigua Harington.