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 (Linne) 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. unicolor (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; sand 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, pi. 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 cerulea. 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., pi. 37 (pt. xxxv.), Dec. 1st, 1848. Mathews, Vol. II., pt. 4, pi. 118, 

 Nov. 1st, 1912. 



Anous cinereus Gould, Proc. Zool. Soc. (Lond.), 1845, p. 104, Feb. 1846 : northern coasts 

 of Australia (? error = Lord Howe Island). 



