(780) Chaptia aenea aenea (Vieill.).
THE NORTHERN BRONZED DRONGO.
Chaptia oenea oenea, Fauna B. I., Birds, 2nd ed. vol. ii, p. 368.
The dividing line between this and the next race is very hard to define ; the extreme Northern birds are decidedly bigger and not so dark as the extreme Southern but, as they grade gradually into one another over an immense area, in which there is no space not inhabited by them, any line of demarcation can only be an arbitrary one. I retain, therefore, the distribution as given in the ‘Fauna’ for the present race, i. e., the Himalayas, from Mussoorie in the West to Eastern Assam and North-East Bengal, Manipur, Chin and Kachin Hills, Yunnan to Hainan ; 1 Saigon.
This little Drongo breeds from the plains up to 4,000 feet and, occasionally, up to 5,000. It does not seem to mind much where the tree is in which it builds its nest, but it certainly has a preference for one which hangs over water or over some jungle-track. It frequents forests of all kinds, other than the deepest and wettest of evergreen. It will, on the other hand, sometimes select a small tree quite in the open or standing in low scrub-jungle. Often it breeds in bamboo-jungle, and will then place its nest either high up on a hanging spray from a waving bamboo or in among the masses of upright twigs which grow from the lower nodes between 5 and 15 feet.
In Nepal Hodgson says that they “breed in the plains near these hills, rarely quitting large woods.” In Sikkim, Gammie writes, “I have found the Bronzed Drongo breeding from April to June in the low hot valleys at about 2,000 feet above the sea. It suspends its nest in a slender horizontal fork at 10 feet or more from the ground and appears, like its frequent neighbour Dicrurus longicaudatus, to prefer a bamboo clump to breed in.” Cripps, in Furreedpore, found a nest “built on a slender twig on the outer side of a mango- tree which was standing near a ryot’s house, and was about 15 feet from the ground.”
In Assam Coltart and I occasionally took them from places as described above, but most often we found them breeding in rather small trees standing in thin forest or open scrub-jungle, and several nests were built on thin scraggy saplings standing at the edge of forest surrounding the various Tea estates.
The nests are very like those of the genus Dicrurus—shallow saucers, built in slender branches in small forks on the outskirts of the tree, and at any height from 5 to 25 feet, generally between 10 and 15 feet. In size the nests would probably average about 3 or 3.1/4 inches in external diameter, with a cavity for the eggs about 1/2 inch less.
In depth they vary greatly, but moat of those I have personally taken have only been about 1.1/2 inch, with very thin bases. One such, which was placed on the upper surface of a rotten branch, just like a Minivet’s, had practically no bottom at all in the centre, the eggs resting on the lichen-covered branch. This nest was also rather exceptional in having the outside well covered with scraps of bark and lichen, though Chaptia certainly adorns its nest outside in this manner more often than does any Dicrurus.
Hume says that the depth in some nests is considerable and "nearly an inch thick at bottom." Like most nests of the Dicruridoe, even those which look fragile are really very strong, as they are well put together and strengthened inside and out with a plentiful coating of spiders’ webs. The materials are just the same as in the nests of Dicrurus.
The breeding season throughout their area seems to be fairly regularly April and May, but some birds breed a little earlier and others a little later. Hodgson says that in Nepal they begin to lay in March, while he took eggs as late as the 6th May, and Cripps took one on the 1st of that month in Eastern Bengal.
In the Northern race the number of eggs laid is almost invariably four, three rarely, while I have once seen five young ones.
I cannot improve on Hume’s description of the normal type of egg, which runs :—“The eggs very much recall the eggs of Niltava and others of the Flycatchers. They are moderately elongated ovals, in some cases slightly pyriform, in others somewhat pointed towards the small end. The shell is fine and compact, smooth and silky to the touch, but they have little gloss. The ground-colour varies from a pale pinkish-fawn to a pale salmon-pink, and they exhibit round the large end a feeble, more or less imperfect and irregular zone of darker-coloured cloudy spots, in some cases reddish, in some rather inclining to purple, which zone is more or less involved in a haze of the same colour, but slightly darker than the rest of the ground-colour of the egg.”
Occasionally an egg of the above type has the blotching distributed more or less over the whole surface and forming no zone at the larger end, though they are more numerous there.
An unusual type of egg, but one which crops up everywhere (taken by myself in North Cachar, Jones in Kanchrapara and Mackenzie in the Chin Hills), has the ground white or nearly so, freely blotched and spotted with reddish primary and grey secondary marks, thick at the larger end and decreasing towards the smaller end. These eggs can be matched in colour with many of the Grey Drongo group. I have also one egg, an addled one, found with two young, with a pale pink ground dotted with deep red-brown, almost black, and lavender. This is like many eggs of the Black Drongo group.
One hundred eggs average 21.1 x 16.1 mm. : maxima 24.1 x 16.0 and 22.2 x 17.2 mm. ; minima 19.9 x 15.9 and 20.0 x 15.0 mm.
Both birds share in the task of incubation, for we have often caught the male on the nest. This seems to be contrary to the general custom of the Drongos. Both sexes also help in building the nest. Hume also refers to this fact and says that “both sexes participate in the work of incubation and in rearing the young.” Incubation, I think, takes only thirteen days.
It is impossible for any one who watches birds and has any idea of their movements and actions to miss a nest, for, no matter how invisible it may be, it is always given away by the anxiety of the parents, who dash wildly out and pursue any other bird which approaches their home.
780. Chaptia senea senea
(780) Chaptia aenea aenea (Vieill.).