(682) Niltava grandis grandis (Blyth).
THE SIKKIM LARGE NILTAVA.
Niltava grandis grandis, Fauna B. I., Birds, 2nd ed. vol. ii, p. 257.
This beautiful Flycatcher is found from Nepal to Eastern Assam, both North and South of the Brahmapootra, to the Chin Hills and Manipur, breeding at elevations between 3,000 and 7,000 feet.
In Sikkim Stevens gives their Summer range as between 4,700 and 6,000 feet, but Gammie found nests up to 7,000 feet round Darjiling.
The site selected for the nest is invariably in fairly thick cover and generally in evergreen forest. Very rarely I have seen the nest built in ravines in bush or bamboo-jungle, but it will only be found in these when there is ample green and mossy undergrowth in the ravine itself. It was a very common bird in North Cachar and in the Khasia Hills, where its favourite resorts were deep and rocky ravines running through dense and humid forest, with a good flow of water along the bottom. Next to these ravines the nests were most often found on the rocky banks of the bigger streams in the same kind of forest. Nearly all the nests I have seen in situ, well over a hundred in number, have been built in among large boulders, in holes of, or in among the long moss growing on, the faces of big rocks beside streams and waterfalls. In nearly every case the surroundings were mossy, and situations are nearly always selected in which long moss conceals the nest from view. In Assam other sites were rare. I have seen one or two nests in holes in dead tree-stumps, one or two others tucked away among the great roots of some forest-tree and yet one or two more built under fallen logs. Rather more often the nest may be placed on steep banks in forest, either among the roots of a tree or in some natural hollow among the undergrowth. Outside Assam, however, their nests have been found built against the sides of trees.
Gammie writes :—“A favourite position for the nest is against the side of a gigantic buttressed tree, about four or five feet up, in the angle formed by two of the buttresses.” A more curious site still is mentioned by Hodgson, who says :—“They are placed on the branch of some tree, between three or four slender shoots, at an elevation of a few feet above the ground.”
The birds often build in places where the nest is constantly more or less wet. In Shillong a pair built annually on a ledge of the rock-face of the Elephant Falls, the spray from which fell over the nest in a shower whenever the falls were swollen by recent rain. Another pair had their nest in a deep crevice in a rock down which, just behind the nest, ran a constant trickle of water which also, when increased by rain, ran over the edge of the nest. In spite of these disadvantages the Flycatchers managed to raise a propor¬tion of their broods each year.
The nest is made entirely of fresh green moss and is lined with the fine roots of the same, well matted and intertwined with one another. Occasionally a few maidenhair-fern rachides or a little rhizomorph of some fungus may be found mixed with the moss- roots.
The nest usually conforms in shape to the hole or crevice in which it is placed and is often very bulky. I have seen nests a full foot across one way and about 8 inches the other, though the inner cup is the usual neat hemisphere, measuring only about 3 inches in diameter by 1.1/2 deep. When it is built against the side of a rock or tree it is a massive cup between 5 and 6 inches in external diameter by about 4 inches in depth. These nests would be circular cups but for the fact that the side against the rock-face is, as a rule, flattened and very thin.
The breeding season is May and June in Assam but, in the Chin Hills, Hopwood took nests with full complements of eggs in the latter half of April. I have also seen one or two belated nests with eggs in the first half of July. They are, I believe, single brooded but, of course, often have a second nest if the first comes to grief before the chicks have attained any size.
The full clutch of eggs is four but I have seen a five, and have also seen three only incubated occasionally.
Many of the eggs could not possibly be distinguished from those of the White-tailed Blue Chat but, as a series, they are decidedly more freckled and blotched and not so unicoloured. The ground¬colour varies from the palest creamy white or pinkish-white to a quite warm buff. Most eggs are distinctly freckled with light reddish or buffy brown, while in a very few the freckles become real blotches. In others, again, the markings are so minute that the eggs look all one colour, except for a faint cloud-like cap at the larger end, where the specks are densest and darkest.
In shape the eggs are broad, blunt ovals, occasionally a little lengthened and slightly compressed at the smaller end. The texture is fine and close and the unicoloured eggs have a distinct gloss, though not so highly developed as it is in Muscisylvia.
One hundred eggs average 24.3 x 17.8 mm. : maxima 26.1 x 18.0 and 23.0 x 19.0 mm. ; minima 20.4 x 17.0 and 21.0 x 16.0 mm.
682. Niltava grandis grandis
(682) Niltava grandis grandis (Blyth).