Order LARIFORMES Family LARIDM. 
No. 139. 
STERNULA NEREIS HORNI. 
WESTEEN WHITE-FACED TERNLET. 
Sterna nereis horni Mathews, Nov. Zool., Vol. XVIII., p. 209, 1912 ; West Australia. 
Sterna nereis (not Gould) Le Souef, Emu, Vol. II., p. 107, 1902 ; Carter, ib., Vol. III., p. 208, 
1904 ; Gibson, ih., Vol. VIII., p. 65, 1908 ; Ogilvie-Grant, Ibis 1910, p. 185. 
Sterna nereis horni Mathews, Nov. Zool., Vol. XVIII., p. 209, 1912 ; id., Austral Av. Rec., 
Vol. I, p. 54, 1912. 
Distribution. West Australia (type from South-west ; Kalgan River). 
Adult male in breeding -plumage. Wings, scapulars, mantle, and middle of back silvery- 
grey, becoming white on the upper tail-coverts and tail ; outermost primary- quills 
shghtly edged with darker on the outer web, and a shade of the same colour on the 
inner web adjoining the shaft ; a spot in front of the eye, hinder part of the crown, 
and nape black ; forehead to the midde of the crown, lores, and entire under- 
surface silvery-white including the axillaries, under wing-coverts, and under tail- 
coverts ; “ Bill and feet orange-yellow, claws brown ; eyes black ” (G. C. Short- 
ridge). Total length 262 mm. ; culmen 34, wing 185, tail 96, tarsus 18. 
Adult female. Similar to the adult male. 
Adult in winter-plumage. Similar to the adult in breeding-plumage, but the black in 
front above the eye less pronounced. 
Immature. Top of head white, nape dull black, tail greyish, otherwise as in adult ; 
“ Iris black, legs brown tinged with yeUow, bill ohve-brown tinged with yellow 
at gape ” (G. C. Shortridge). 
Nestling {flying). Forehead and fore-part of head white, back of head and neck blackish- 
brown and white tipped with buff ; primaries and primary-coverts deep grey, 
most of the inner w^ebs white ; greater series of wing-coverts dark grey, median 
and lesser lighter grey, some of the median with brown spots ; feathers of back and 
scapulars with brown spots and tipped with buff ; tail white, faint brown tips to 
centre feathers. 
Nestling (younger). “Cream with longitudinal chestnut markings” (Le Souef). 
Nest. A depression in the sand. 
Eggs. Clutch, two ; similar to those of S. nereis nereis ; axis 35-36 mm., diameter 25-26. 
Breeding-season. November (Gibson) ; December. 
Mr. Le Souef* says he found this bird on the islands about fifteen miles 
south of Fremantle : “ We then made for the far side of the bay, where, separated 
by a narrow channel from the mainland, was a low sandbank, about an acre in 
* Emu , Vol. II., p. 107, 1902. 
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