(1814) Accipiter virgatus affinis.
THE NORTHERN- BESRA SPARROW-HAWK.
Accipiter affinis Hodgs., Beng. Sport. Mag., New Series, viii, p. 179, (1836) (Nepal). Accipiter virgatus. Blanf. & Oates, iii, p. 404 (part.).
Vernacular names. As in A. v. besra.
Description.— Adult male. Similar to the preceding bird but above much darker, more blackish-grey throughout, the head hardly darker than the back; below the colouring is also rather richer and deeper if stage by stage is compared.
Colours of soft parts as in the Southern Besra.
Measurements, wing 165 to 175 mm.; culmen 16 to 17 mm. , wing 197 to 210 mm.; culmen 18 to 20 mm.
Female. This differs from the Southern Besra in being a darker chocolate-brown above and especially in its much darker slaty-black crown and nape ; below there seems to be little difference.
Young birds appear to be darker brown and edged with rufous of a richer tint.
Distribution. Breeding Himalayas from the extreme West to Yunnan and the Western Chinese Hills. South it breeds in the Assam and Sarrma Valley ranges, as well as in Manipur, Lushai and the higher ranges of Northern Burma. In Winter it is found over the greater part of Northern India.
Nidification. The Northern Besra breeds during April and May, making a nest, on the basis of some old nest, in .much the same manner and situation as the Southern bird. It breeds from quite low down—I have taken one nest at 1,500 feet—up to at least 7,000 feet. As a rule, the birds do not go beyond protests, very noisy and vehement, when their eggs or young are interfered with but occasionally both parents will make repeated swoops at the intruder. The eggs number three or four, rarely five and occasionally two only. They cannot be distinguished from those of the preceding bird though, as would be expected, they average! a little bigger, the average of fifty being 37.7 x 30.0 mm.: maxima 40.4 x 30.8 and 38.3 x 32.2 mm.; minima 35.0 x 29.6 and 38.4 x 28.8 mm.
Habits. Similar to those of the Southern form. Most of the birds obtained in Cachar had fed principally on insects but I have seen remains of small flying squirrels, mice, bats and birds, such as barbets, thrushes and bulbuls on and under their nests. They are very quick on the wing and I have seen them capture the small swift, Tachornis b. infumatus. They are jealous birds and allow no other Sparrow-Hawks to enter their particular piece of forest. In Winter they descend into the plains and at this time keep much less to forest and may be seen in fruit-groves and well-wooded open country.