Order LARIF0RME8 
No. 125. 
Family LARIDM. 
HYDROCHELIDON LEUCOPAREIA FLUVIATILIS. 
EAST AUSTRALIAN WHISKERED TERN. 
Hydeochelidon FLUVIATILIS Gould, Proo. Zool. Soo. (Lond.) 1842, p. 140, 1843 ; Interior 
of New South Wales. 
Hydrochelidon fluviatilis Gould, Proc. Zool. Soc. (Lond.) 1842, p. 140, 1843 ; id., Birds 
Austr., Vol. VII., pi. 31, 1848 ; Sturt, Narr. Exped. Oentr. Austr., Vol. II., App., 
p. 58, 1849 ; Mathews, Emu, Vol. X., p. 320, 1911. 
Hydrochelidon leucopareia Gould, Handb. Birds Austr., Vol. II., p. 406, 1865. 
Hydrochelidon hyhrida Ramsay, Proc. Linn. Soc. N.S.W., Vol. II., p. 201, 1877; id.. 
Tab. List Austr. Birds, p. 23, 1888 ; North, Austr. Mus. Cat., No. 12, pp. 353, 
402, 1889 ; Saunders, Oat. Birds Brit. Mus., Vol. XXV., p. 10, 1896 (pars) ; North, 
Birds County Cumber., p. 112, 1898 ; Keartland, Trans. Roy. Soc. South Austr., 
Vol. XXII., p. 191, 1898 ; Hall, Key Birds Austr., p. 87, 1899 ; Campbell, Nests 
and Eggs Austr. Birds, p. 829, 1901 ; Belcher, Emu, Vol. II., p. 33, 1902 ; Hall, Key 
Birds Austr., p. 87, 1906 ; Mathews, Handl. Birds Austral., p. 20, 1908. 
Hydrochelidon leucopareia fluviatilis Mathews, Nov. Zool., Vol. XVII., p. 497, 1910 ; id., ib., 
Vol. XVIII., p. 207, 1912. 
Distribution. East and South-east Australia. 
Adult in breeding-plumage. Similar to H. leucopareia rogersi, but the upper coloration is 
shghtly darker while the under surface is darker, more especially noticeable on the 
upper-breast ; the bill is also stouter, and the axiUaries are distinctly pale grey ; 
the axiUaries in H. 1. rogersi are pure white. 
Adult in winter-plumage. I have only examined birds in the change, and they differ 
from the same plumage of H. 1. rogersi in the stouter bill. 
Immature and Nestling. Appear to be undescribed. 
Nest. “ Built up from the bottom, in water about two feet deep, the under part formed 
of dry stalks of slender reeds ” (Belcher). 
“ Composed of green rushes, in most cases quite flat, the whole structure floating 
on the surface of the water ” (Bennett). 
Eggs. Clutch, two to three ; ground-colour greenish-buff, blotched all over with blackish ; 
with some underlying ones of grey ; axis 35 to 38 mm., diameter 27 to 28. 
Breeding-season. October, November, and December (Bennett). 
All observers have commented on the grace of these birds as they fly over the 
inland waters near which they make their home. Their progress is easy and 
graceful, every now and then darting down into the water after food, which 
consists of hve fish mostly, but they do not dive right under water. 
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