Birds of Celebes: Laridae. 



907 



Immature. Similar to the adult in winter plumage, but with the feathers of the upper parts 

 tipped with wliitish, and head above browner ((f , Bonthain, S, Celebes, 15. Jan 1895- 

 P.&F. Sarasin). 



Young. "Head streaked and mottled with brownish black; feathers of the upper parts dark 

 brown with rufous tips, which subsequently become paler, approaching white, and 

 finally wear away; under parts greyish white; bill and toes brownish" (H. Saunders 10). 



Measurements. Wing 240— 278 mm (the smallest being the above immature bird fi-om Bonthain, 

 the largest an exceptionally large example from Sangi measured by Prof. W. Blasius), 

 tail c. 170, depth of fork c. 100; tarsus 22; middle toe with claw 29; exposed cuhnen 

 c. 40—45. 



Eggs. J , sometimes 2. "The eggs have a white ground, violet shell-spots, and light and dark 

 brown superjacent spots, some sharply defined, some washy. The variabihty is very 

 great. Size 50—51 x 35—36 mm" (Nehrkorn MS); see, also, Finsch & Hartlaub 

 b 2, with figures; Heuglin b 5; Baird, Brewer & Ridgway 5; North 7; Hume 

 fl; etc. 



Nest. None. The egg (or eggs) is laid in a depression in the sand near liigh-water mark, 

 or among fragments of rock, or in clefts of the rocks, or in holes dug in the ground 

 to a depth of 1 to l'/2 feet, or under a tuft of grass, or under a small bush. Gene- 

 rally rather well concealed (S, h 3, 7, etc.). 



Distribution. From the Gulf of Mexico and the West Indies to W. Africa; the coasts washed 

 by the Indian Ocean and its seas, including the East India Archipelago and Australia; 

 the Western Pacific Ocean from Japan to the Phoenix and Tonga Islands (see 

 H. Saunders 10). — In the Oelebesian area: Great Sangi Island (Platen e 6); 

 Celebes — S. Peninsula at Bonthain (P. & F. Sarasin); Saleyer Island (Wallace 

 e 2, 10). 



Up to the present time we know of only one example of this wide-ranging 

 Tern from the mainland of Celebes, the immature male obtained by the cousins 

 Sarasin in the South. There is an immature example from Saleyer from Mr. 

 Wallace in the British Museum, and a male of unusually large size, as Prof. 

 W. Blasius shows, from Great Sangi in the Brunswick Museum. 



The Brown-winged Tern is easily distinguishable from the other Terns, 

 breeding in or visiting Celebes, by its brown upper parts and white under sur- 

 face. Its toes have the webs somewhat deeply indented, and in this respect it 

 forms an approach to the genus Hydrochelidon, as it does also by its somewhat 

 thin, sharply pointed bill and by its tendency to dusky hues; but its tail- 

 feathers, lengthened laterally into rather long streamers, as well as its marine 

 habits, serve to separate it from that genus. It has the wing of a bird of great 

 flying powers — lengthened primaries, the inner ones with the ends somewhat 

 angularly cut, and short secondaries, and Heuglin describes it as the predicate 

 of a perfect flier; its movements in the air, even against strong breezes, are as 

 active as strong, light, soft, and enduring. With two other species, Sterna 

 fuliginosa Gm. inhabiting the warmer seas of the globe, and S. lunata Peale from 

 some of the warmer parts of the Western Pacific, east to Hawaii and the 

 Paumotu Islands, the present species has been placed in the genus Onychoprion, 

 which has this peculiarity amongst others, of usually laying only a single egg; 



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