Caprimulgus griseatus Walden, Trans. Zool. Soc. (1875), 9, pt. 2,
160; Tweeddale, Proc. Zool. Soc. (1877), 691; Hartert, Cat. Birds
Brit. Mus. (1892), 16, 550; pl. 11; Grant and Whitehead, Ibis
(1898), 245, pl. 6, fig. 7 (egg); Clarke, Ibis (1900), 353; Sharpe,
Hand-List (1900), 2, 86; Oates and Reid, Cat. Birds' Eggs (1903),
3, 67; McGregor and Worcester, Hand-List (1906), 57; Worcester,
Phil. Jour. Sci. (1907), 2, sec. A, 271, pls. 1 & 2.
Catanduanes (Whitehead); Cebu (McGregor); Luzon (Everett,
Whitehead, McGregor); Mindanao (Goodfellow); Mindoro (McGregor,
Porter); Negros (Keay); Sibuyan (Bourns & Worcester, McGregor).
Adult male.--Upper parts finely vermiculated with blackish brown,
pale buff, and gray, more heavily marked with blackish brown on top of
head and on scapulars, some of the latter with wide edges of fulvous
or buff on outer web; an obsolete collar of buff on hind neck; lower
parts finely marked with blackish brown, buff, and whitish buff; a
large white patch on each side of throat; some of the breast-feathers
with rather large, pale buff, terminal spots; lower breast, flanks,
and abdomen buff, rather narrowly barred with brown, less closely
barred posteriorly; under tail-coverts very pale buff or white and
unbarred; inner primaries, primary-coverts, and outer secondaries
strongly barred with rich fulvous; first primary with a large white
spot reaching shaft; second, third, and fourth primaries each with a
buff-margined white spot crossing both webs and involving the included
section of shaft; exposed portion of each of the two outer pairs of
rectrices with a large terminal white area, a dusky wash near the
tip; rectrices barred basally with buff and dark brown. A male from
Mariveles measures: Length, 228; wing, 170; tail, 103; tarsus, 18;
middle toe with claw, 25.
Adult female.--Differs from the male in lacking the terminal white
area on tail-feathers which are barred and mottled with pale buff and
dark brown; on the outer feather there is an ill-defined light buff
area at tip of inner web. A female from Mariveles measures: Length,
228; wing, 164; tail, 100; tarsus, 18; middle toe with claw, 26.
Young.--Upper parts blackish brown, very finely vermiculated with white
and lacking the black blotches and fulvous edges to scapulars which
are present in the adult plumage; under parts about the same shade
of gray as in the adult but more finely and more uniformly mottled
and barred and without fulvous or buff spots on breast; white spots
on throat just indicated; wings and tail similar to the adult.
Eggs.--Whitehead took two eggs of this species at Cape Engaño,
Luzon, May 26, 1895, which he described as follows: "Shape elliptical
oval; ground-color pale creamy white, with very pale lavender-gray
under-markings and very pale brownish over-markings; the blotches and
markings, none of which are very large, are unevenly distributed over
the whole surface; measurements 31 by 22 mm. The eggs were placed on
the sand just above high water mark among sea drift, which, in this
instance, consisted of huge tree trunks. Both birds were seen and
identified beyond doubt." (Grant and Whitehead.)
The gray nightjar appears to be confined to the vicinity of sandy or
shingle beaches and while abundant in the localities where it has been
discovered the species has been recorded from but few islands and the
female and young have been but recently described. The description
of the eggs was published two years before that of the female.
Clarke says with feeling that the female "is not an easy specimen
to describe," but it is much easier to describe a single specimen
than to write anything that will apply to the variations which occur
in the species. In using the descriptions given above considerable
allowance must be made for variation in the shade of buff or fulvous;
this refers particularly to the scattered spots on breast, the broad
edgings of scapulars, and the rusty bars on primaries, primary-coverts,
and secondaries, all of which vary from a light buff (even almost white
on edges of scapulars) to rich fulvous. These variations are probably
due to age, the parts becoming darker with successive molts. In two
females from Mariveles, Luzon, the buff spot on first primary does
not reach the shaft.