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 sribsequently become paler, ajiproaching white, and 
finally wear away; under parts greyish white; bill and toes brownish” (H. Saunders JO). 
Measurements. Wing 240 — 278mm (the smallest being the above immature bird from Bonthain, 
the largest an exceptionally large example fr-om Sangi measured hy Prof. W. Blasius), 
tail c. 170, depth of fork c. 100; tarsus 22; middle toe with claw 29; exposed culmen 
c. 40—45. 
Eggs. 1, sometimes 2. “The eggs have a white gi'ound, violet shell-spots, and Mght and dark 
brown superjacent spots, some sharply defined, some washy. The variability is very 
great. She 50 — 51 X 35 — 36 mm” (Nehrkorn MS); see, also, Finsch & Hartlaub 
d 2, with figures; Heuglin b 3; Baird, Brewer & Eidgway 5; North 7; Hume 
.9; etc. 
Nest. None, The egg (or eggs) is laid in a depression in the sand near high-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 [9, b 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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