GREY NODDY. 103 
portions, remainder black ; a blush of hoary-grey pervades the sides of the face 
and hind-neck ; under wing-coverts plumbeous-black ; bill and feet black. Total 
length 395 mm. ; culmen 39, wing 262, tail 150, tarsus 26. 
Adult female Similar to the adult male but browner in colour and somewhat 
smaller. 
Immature—Uniform, brown, without a cap. 
Nestling (two days old) —Covered with down, sooty-brown on the upper-surface 
as well as on the throat, fore-neck and chest, becoming paler and inclining to white 
on the abdomen, with the fore-head dirty white, darker on the top of the head, only 
an indistinct cap being seen. 
Nest.—Constructed of seaweed, about six inches in diameter, and varying in 
height from four to eight inches, but without anything like regularity of form ; the 
top is nearly flat, there being but a very slight hollow to prevent their single egg from 
rolling off. 
Egg.—Clutch, one ; ground-colour light stone ; spotted on the larger end with 
reddish-brown and sparsely spotted all over with dull grey ; axis 54-56 mm., diameter 
36-38. 
Breeding-season.—October to January. 
Distribution and forms.—Throughout the tropical oceans, breeding on isolated 
islets. Mathews differentiated eight forms and has since added a ninth; these 
are as follows: A. s. stolidus (Linné) from the Atlantic Ocean; A. s. rousseaui 
Hartlaub from Madagascar, Mauritius, etc., in its larger size and darker coloration ; 
A. s. plumbeigularis Sharpe, from the Red Sea, in its smaller size and slightly paler 
coloration ; A. s. pileatus (Scopoli) from the Philippine Islands, Liu Kiu Islands, 
and China Seas in being darker and again larger ; A. s. wnicolor (Nordmann), from 
the South Pacific Islands (Society, Paumotu, etc.) in its still larger size; A. s. 
gilberti Mathews from West Australia, lighter and larger than A. s. pileatus and 
smaller than A. s. unicolor; A. s. antelius Mathews from East Australia, browner 
with head lighter and with longer wings; A. s. galapagensis Sharpe from the 
Galapagos Islands with its dark blackish coloration and dark grey cap, a very distinct 
form; and A.s. ridgwayi Anthony from the Pacific Coast of Mexico, paler than 
preceding, but darker than A. s. stolidus, the top of the head darker grey, etc. 
Genus PROCELSTERNA. 
Procelsterna Lafresnaye, Mag. de Zool., 1842, pl. 29. Type (by monotypy): P. tereticollis 
= Sterna cerulea Bennett. 
Small Noddies with short slender bills, long wings, long tails, and long toes 
fully webbed. 
The tail has the outer rectrix shorter than the second, which is longest, but 
longer than the middle feathers. The middle toe without the claw is about the 
same length as the exposed portion of the culmen and longer than the metatarsus. 
The tail is slightly more than half the length of the wing. 
Coloration all bluish-grey. 
Procelsterna ceruleak—GREY NODDY. 
[Sterna cerulea Bennett, Narr. Whaling Voy., Vol. II, p. 248, (pref. April 14th) 1840: 
Christmas Island, Pacific Ocean. Extra-limital.] 
Gould, Vol. VII., pl. 37 (pt. xxxv.), Dec. Ist, 1848. Mathews, Vol. II., pt. 4, pl. 118, 
Nov. Ist, 1912. 
Anous cinereus Gould, Proc. Zool. Soc. (Lond.), 1845, p. 104, Feb. 1846: northern coasts 
of Australia (? error = Lord Howe Island). 
