(1815) Accipiter gularis gularis.
THE JAPANESE SPARROW-HAWK,
Astur gularis Temm. & Schleg. in Sieb. Faun. Jap., p. 5 (1845) (Japan).
Vernacular names. None recorded.
Description. Plumage generally like that of other Sparrow-Hawks ; the upper parts are blackish-slaty throughout, the rump but little paler than the head; the white marks on the nape and supercilium obsolete or, rarely, entirely absent; the ear-coverts are pale grey or vinous-grey, hot mixed with chestnut or white as in the Indian forms of nisus; below the,plumage varies from smoky vinous-white to ferruginous, the chin and' throat white with a narrow black1 mesial line; there are faint traces of darker or paler barring on the abdomen and lower breast even in the oldest birds; under tail-coverts white ; tail with four broad bands of blackish.
Colours of soft parts. Iris crimson (La Touche), straw-yellow in the female (Whitehead); bill slaty-blue, tipped black; cere and legs yellow, claws black.
Measurements. wing 165 to 173 mm.; culmen 14 to 15 mm. wing 186 to 198 mm.; culmen 16 to 18 mm.; tarsus 51 to 54 mm.; tail 117 to 137 mm.
Females are dark brown above, the head blackish-brown; there is a distinct mesial line on the throat and in fully adult birds barring on the whole of the lower parts from fore-neck to vent, the under tail-coverts alone being white.
Young birds are brown above, the feathers edged with buff: or rufous, the head brown like the back ; the mesial throat-streak is broader and the breast is marked with broad brown streaks, not barred; remainder of plumage as in the female; the outermost tail-feathers have five or six bars; the under tail-coverts are occasionally marked with a little brown in bars or streaks.
Distribution. North China to Japan, wintering as far South as the Philippines, Malay Archipelago and, rarely, Burma and even India.
Kirke-Swann records variation of depth, of under plumage in males according to geographic distribution but the material in the British and Tring Museums is amply sufficient to show that it is individual only.
Nidification. This Sparrow-Hawk breeds in Japan in May and June, according to Ouston, principally in old nests of Crows. In a clutch of five sent to me the eggs vary from 38.8 x 32.1 to 40.8 x 31.4 mm.; these two eggs embracing all four extremes of measurement.
Habits. This is migratory bird, wandering very far in the Winter months, when it may be seen in the same country as the next two forms and, as the youngest birds travel farthest, it has been most difficult to determine the subspecific differences between them, the disentanglement being due to Robinson. In habits they seem to be very similar to the Common Sparrow-Hawk.