(1728) Falco severus severus Horsf.
The BURMESE HOBBY.
Falco severus severus, Fauna B. I., Birds, 2nd ed, vol. v, p. 45.
This handome little Falcon is a resident breeding bird from Assam, Cachar, Manipur, the whole of Burma from the Northern hills to Tenasserim ; Siam ; probably the Malay States, to the Philippines. It has also been recorded from Trangbong in Cochin China. It occurs in the hill country only, I believe, but at no very great elevations. In North Cachar (Journ, Bomb. Nat. Hist. Soc. vol. xi, p. 403, 1898) I saw its nest, which I could not get at, at about 2,500 feet, while in the Khasia Hills several pairs bred in the precipitous hills facing the Sylhet district, between 3,000 and 4,000 feet. Macdonald also found a nest with one young bird in Pakokku (ibid, vol. xvi, p. 518, 1905).
This is a Falcon of well-wooded country and even of forests, hut it prefers wide open spaces with ample tree-growth and not much underwood.
In the Assam Hills we found them breeding only on precipitous cliff-sides, sometimes heavily wooded on the lower slopes but, generally, only scantily dotted with trees and bushes on the higher parts, which were for the most part too steep, and with too little soil, except in the crevices and on the ledges, for much vegetation. Here the birds made use of an old nest of a Crow, Magpie or Wood- Pigeon. Sometimes, beyond adding a little lining, practically nothing more was done to the nest but, at other times, the birds would add much material and a fine lining of leaves and green twigs.
Occasionally I think these Falcons make nests for themselves in trees. One nest I found at Lilancote was built in a small tree growing out of a deft in a steep hill-side and was made of fine, rather long twigs, none as thick as a pencil and, when first found, all fairly new and fresh, as was the lining of leaves and twigs. A second nest belonging to this same pair of Hobbies, some 200 yards away, was similar in position and make and had also, I believe, been made by the birds themselves.
These nests, though quite unapproachable from above, were easily climbed up to from below, and of all the nests I have seen of this Hobby only two defeated us, and even these might have been reached with ropes had they been available. At the same time they always, in my experience, choose sites on cliff-sides or the faces of very steep bills, and I have seen none on the flat. Occasionally the birds find or make a nest on the ground on a ledge of rock or earth and, in such cases, it may consist of a very meagre collection of a few sticks or tufts of coarse grass. K. C. Macdonald (loc. cit.) says : “On the 13th May I found the Indian Hobby (F. severus) breeding on the banks of the Nugittha River in this district. The nest was in a hole in the cliff about 30 feet above the water-level. I should rather say the solitary young bird was in the hole, as there was no nest.”
Most pairs of Hobbies seem to have alternate nests for laying in, and we found these sometimes quite close to one another and at other times at considerable distances apart. In one instance the two nests were not separated by more than 200 yards, but in another they were over half a mile apart. Each pair, however, nearly always selected similar sites for the two abodes. One pair chose quite small trees growing out of crevices in precipices, another tall Pine-trees growing on precipitous and heavily-wooded sides of very steep hills, while yet a third pair had both their nests on ledges of rock on cliff-faces ; these nests seemed to be occupied in no particular order or system, though when a nest was robbed the birds nearly always went to the second nest, in which they laid another clutch which we never interfered with.
The breeding season is from the last week in March to the first week in May, but I have taken eggs as late as the 19th June, though I think these were a second laying.
The eggs are like those of the English Hobby but, on the whole, better and more richly marked. The ground is a buff, reddish buff or light rich brick-red. In some eggs the whole surface is almost obliterated with dark brick-red, brownish-red or purplish red specks but in some the markings are bolder, richer and stand out more from the ground-colour, somewhat approaching Merlin’s eggs in type. Almost unicoloured brick-red eggs are not rare.
In shape they are broad ovals ; the texture is fairly fine and close but the surface has no gloss.
Fifty-four eggs average 40.1 x 31.9 mm. : maxima 41.4 x 33.0 and 41.1 x 34.0 mm. ; minima 37.1 x 30.9 and 38.4 x 30.0 mm.
Both birds incubate and both assist in the nest work, but I think the male does the bringing of the material and the female does the patch-work.
Incubation takes twenty-six days. A clutch taken in April was replaced with four eggs on the 27th May, when the hen began to sit, and the first egg hatched on the 16th June and the three others the next day. The young stayed in the nest for over a month.
When a nest is robbed the birds both fly screaming overhead but will not attack the intruder.
1728. Falco severus severus
(1728) Falco severus severus Horsf.