Circus spilonotus Kaup, Cont. Orn. (1850), 59; Sharpe, Cat. Birds
Brit. Mus. (1874), 1, 58; Hand-List (1899), 1, 245; Blanford,
Fauna Brit. Ind. Bds. (1895), 3, 388; Oates, Cat. Birds' Eggs
(1902), 2, 236; McGregor and Worcester, Hand-List (1906), 40.
La-uin', Manila; ma-na-o', Calayan, all species of small hawks.
Batan (Edmonds); Calayan (McGregor); Luzon (Heriot, Whitehead);
Mindanao (Platen); Mindoro (Everett); Palawan (Whitehead,
Everett); Sulu (Guillemard). Eastern Siberia; in winter to China,
Indo-Burmese countries, and Malay Archipelago.
Adult male.--Above black, nape and hind neck narrowly streaked with
white; feathers of lower back and rump tipped with ashy gray or white;
sides of head and ear-coverts black; lower parts white; chin, throat,
and breast with bold black shaft-streaks; primaries black, white for
basal third; alula, primary-coverts, and secondaries ashy white with
blackish shafts; secondary-coverts black, more or less mixed with
ashy white; under coverts and axillars white; tail ashy white; upper
tail-coverts white. Iris bright yellow; legs dull yellow; cere waxy
green; bill and nails black. The above specimen from Tarlac Province,
Luzon, measures, 520 in length; wing, 410; tail, 230; culmen from base,
33; tarsus, 92; middle toe with claw, 63.
Younger male.--Color pattern similar; upper parts brown; white streaks
on head and neck more numerous; under parts white with wider streaks of
reddish brown which are also present on flanks and abdomen; primaries
black, some of them barred with ashy white; wing-coverts brown with
less white than the adult; primary-coverts and alula ashy white but
with blackish brown bars; under wing-coverts white, streaked with
blackish brown; axillars white, streaked and barred with reddish
brown. Length, 533; wing, 400; tail, 235; culmen from base, 32;
tarsus, 80; middle toe with claw, 61.
"Adult female.--Above brown slightly shaded with ashy, the dorsal
feathers obsoletely margined with dull rufous; crown and hind neck
tawny-buff, paler on the neck, all the feathers mesially streaked
with brown; scapulars and wing-coverts margined and barred with tawny
or fulvous, the least wing-coverts more conspicuously margined with
rufous; quills brown, narrowly tipped with whitish, externally shaded
with ashy gray, the secondaries less distinctly, and all barred across
with darker brown; under surface of wing white, the dark bars showing
very distinctly; lower back and rump brown, the feathers distinctly
tipped with pale rufous; upper tail-coverts pure white; tail ashy
gray, tipped with fulvous and crossed with five blackish bands, the
subterminal one much the broadest, the ashy gray interspaces inclining
to or replaced by pale tawny on the outer feathers; lores as well
as a distinct eyebrow and ear-coverts buffy white; sides of face
and of neck, as well as the facial ruff, rufous-buff streaked with
dark brown; under surface of body creamy buff, with central pointed
marks of rufous-brown to the feathers, more distinct on the fore
neck and under wing- and tail-coverts; flank-feathers and axillars
rufous-brown, with large rounded spots of creamy buff on both webs;
under wing-coverts and thighs creamy buff, with irregular central
streaks of rufous-brown occupying the major part of the greater under
wing-coverts. Length, 584; wing, 394; tail, 279; tarsus, 79." (Sharpe.)
"Adult female.--Brown above, the feathers throughout with pale
rufous edges; tail-coverts white and rufous; tail with about six dark
cross-bands, which disappear in old individuals; lower parts buff,
with broad rufous-brown shaft-stripes. The quills are dark brown but
become grayish in old birds.
"Young birds so closely resemble those of C. æruginosus as to be
indistinguishable at times. The pale head and neck-feathers are
always striated in C. spilonotus, but the body, wings, and tail are
uniform brown or variegated with buff on the wing-coverts, back,
and breast. Generally, though not invariably, traces of bars will
be found on some of the tail-feathers of C. spilonotus, but this
occasionally happens in C. æruginosus also.
"Length, of male, 508; tail, 235; wing, 394; tarsus, 89; tail of
female, 254; wing, 419; tarsus, 94." (Blanford.)