Microhierax Sharpe, Cat. B.M., i, p. 366 (1874).
Type, Falco fringillarius Drap.
The genus Microhierax contains five species of pigmy Falcons, or Falconet s, tiny Raptores with the carriage and wonderful eye of the fiercest Eagle, and habits which, almost alone, would justify their separation from the other Accipitres.
The bill is large, slightly compressed, with a very large tooth on the upper mandible, sometimes with a second and smaller anterior tooth; the wings are long in proportion to the size of the bird but are rather rounded, the second and third primaries are longest, the first and fourth sunequal and nearly as long; the tail is long and nearly square ; the tarsi and toes powerful with strong claws and the lateral toes nearly equal in length and not much shorter than the middle toe; the tarsus is feathered about half-way down.
Key to Species.
A.No white collar.
A.Thigh-coverts black............... M. fringillarius, p. 51.
B.Thigh-coverts and lower plumage white…………M. melanoleucus, p. 54.
B.A white collar............... M. coerulescens, p. 52.
It is doubtful whether caerulescens should not be treated as a subspecies of fringillarius but in the fine series in the British Museum, consisting of twenty-five specimens of the latter from South Tenasserim and seventeen of the former from North Tenasserim, I can find no intermediate forms. Each individual specimen can, without hesitation, be assigned to one or the other species and I therefore for the present give fringillarius the status of a full species.