Order LABIFORMES 
No. 126. 
Family LABIDJE. 
HYDROCHELIDON LEUCOPAREIA ROGERSI. 
WEST AUSTRALIAN WHISKERED TERN. 
(Plate 103.)* 
Hydeochelidon leucopaeeia eogersi Mathews, Nov. Zool., Vol. XVIII., p. 207, 
1912 ; North-west Austraha. 
Sterna gracilis (not Gould) Ingram, Ibis 1907, p. 392. 
HydrocTielidon hyhrida (not Pallas) Hall, Emu, Vol. II., p. 67, 1902 ; Carter, il)., p. 104 ; 
Mathews, ih., Vol. IX., p. 54, 1909 ; Crossman, id)., Vol. X., p. Ill, 1910. 
HydrocTielidon leucopareia rogersi Mathews, Nov. Zool., Vol. XVIII., p. 207, 1912. 
Distribution. North-west Australia ; Northern Territory. 
Adult male. General colour pale grey including the back, wings, and tail ; outer web of 
first primary dark brown, and showing scarcely any grey, the remainder silvery- 
grey on the outer webs, darker at the tips, and on the inner webs near the shafts 
as also the inner margins ; basal portion of inner webs white, which extends in a 
narrow line towards the tips of the feathers ; inner primaries and secondaries 
pale grey with white on the inner webs ; tail pale grey, the outer feathers margined 
and tipped with white ; head and hind-neck black ; sides of face, throat, under 
tail-coverts white, hke the axillaries and under wing-coverts ; fore-neck pale grey ; 
breast and abdomen dark slate-colour, more intense on the latter ; “ Bill 
dusky red, base of upper mandible black, tinged with red ; iris blackish-brown ; 
feet and legs red” (J. P. Rogers). Total length 274 mm. (“in the fiesh, 269 mm.” — 
J. P. Rogers) ; culmen 31, wing 231, tail 90, tarsus 23. 
Adult female. Similar to the adult male, but paler on the upper-parts and the dark slate 
grey of the under-parts restricted to the abdomen, the breast being similar to the 
fore-neck. Total length, “ m the flesh, 250 mm.” (J. P. Rogers) ; cuhnen 28, 
wing 213, tail 70, tarsus 22. 
Adult male in winter. Differs from the adult male in breeding-plumage, in having the crown 
of the head white with minute pear-shaped black spots, which increase in size on 
the nape ; the ear-coverts dusky-black, and the entire under surface pure white. 
A male example, which I do not consider to be quite adult, appears to be just 
assuming the breeding-plumage, and has the head black with the remains of white 
feathers intermixed, and the dark lead-grey of the breast approaching. 
Immature. Almost pure white below with only a tinge of grey on the abdomen ; more 
or less streaked with dusky on the lesser wing-coverts ; head black with a mixture 
of white on the forehead ; feathers of the nape black, with a brownish tinge. 
* The Plate is lettered HydrocTielidon hybrida . 
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