SOOTY TERN. 99 



Most writers upon the Terns have intimated their disapproval of lumping this 

 species in with Sterna, but have all been unable to find distinct structural differences 

 in the skin to justify the separation. The nature of the young has influenced us 

 in accepting Onychoprion, while most writers have commented upon its habit of 

 laying one egg only. 



71. Onychoprion fuscatus. SOOTY TERN. 



[Sterna fuscata Linne, Syst. Nat. 12th ed., p. 228, (pref. May 24th) 1766: Santo Domingo, 



West Indies. Extra-limital.] 



Gould, Vol. VII., pi. 32 (pt. xxvm.), Sept. 1st, 1847. Mathews, Vol. II., pt. 4, pi. 113, Nov. 



1st, 1912. 



Sterna serrata Wagler, Natur. Syst. Amphib., p. 89 (note), 1830 (ex Forster MS.) : New 



Caledonia. 



Sterna melanura Gould, Synops. Birds Austr., pt. iv., App., p. 7, April 1st, 1838 : New South 



Wales. 



Sterna gouldii Reichenbach, Aves Natat. Longip., pi. XXII., f. 829, 1848 : West Australia. 



Onychoprion fuscatus kermadeci Mathews, Austral Av. Rec., Vol. III., pt. 3, p. 55, April 



7th, 1916 : Kermadec Islands = Long Reef, Sydney. 



DISTRIBUTION. Tropical Australian Seas. 



Adult male in breeding-plumage. Crown of head and nape black, as also a line 

 of feathers from the gape to the eye ; hind-neck, back, scapulars, wings and tail 

 sooty -black ; the small coverts along the upper margin of the wing white ; inner 

 webs of secondaries whitish towards the base ; outer tail-feathers greyish-brown, 

 darker towards the tips on the inner webs ; fore-head and a narrow line to above the 

 middle of the eye white ; sides of neck, throat, and under-surface of body also white, 

 becoming shaded with grey on the lower -abdomen, under tail -coverts, axillaries, 

 and under wing-coverts ; bill and feet black ; iris black and white. Total length 

 475 mm. ; culmen 42, wing 304, tail 210, tarsus 24. 



Adult female. Similar to the adult male, but smaller in every dimension. 

 Adult in winter-plumage. Similar to the adult in breeding-plumage, but the 

 lores and crown of head intermixed with white and black. 



Nestling (a few hours old). Covered with dirty white down, more inclining to 

 white on the abdomen ; bill yellowish, tip black ; iris deep brown ; feet and legs 

 nearly black. 



Nestling (three days old). A mixture of brown, black, and white down on the 

 upper-surface, somewhat darker on the lores and sides of face ; under-surface white, 

 with indistinct dark pectoral band and ashy-black throat. 



Progress of young. South Island, Houtman's Abrolhos : 



January Ylik, 1843. In down. Mottled brownish and white above and on sides 

 of the breast ; under-surface white. 



January 30th, 1843. Fore-head and throat and flanks still down covered. Head 

 dark brown with darker tips ; all back, wing- and tail-feathers brown, with more 

 or less extensive white tips ; under-surface ashy-brown with white patch on the 

 abdomen. 



February I6th, 1843. No down remaining. Wing- and tail-feathers half grown. 

 Head and under-surface all brownish, lighter on flanks ; under tail-coverts paler 

 with rufous tips ; back and tail, scapulars and lesser wing-coverts faintly rufous 

 and tipped with white ; primaries untipped. 



Kermadecs. About the same age as second above. Has down remaining on head, 

 which shows slightly rufous tips underneath ; the general upper coloration is slightly 

 darker, while the tips on the back, wing-coverts and tail-feathers are distinctly 

 rufous, those on the scapulars being rufous-white ; the under-surface is darker 

 and more mottled with greyish-white. 

 Kermadecs. Slightly older than third above, about ready to fly. Has the head 



H 2 



