BASS STRAIT TERN. 
Adult female. Similar to the adult male ; cuhnen 52, wing 326, tail 164. 
Adult in winter-plumage. Differs from the adult bird in breeding-plumage by the 
absence of the black on the crown of the head ; the feathers on the fore-part of 
the head, face, and sides of nape with white margins, becoming black on the 
occiput. 
Immature female. Differs from the adult female in having some of the feathers of the 
upper-back with dark shaft-streaks, the lesser wing-coverts rusty-brown, bastard- 
wing and primary-coverts brown ; primary-quills brown, inner webs white ; 
secondaries white with brown on the outer webs, middle tail-feathers white tipped 
with grey, outer feathers brown with white on the inner webs, the outermost pair 
white tipped with brown ; the feathers on the fore-part of the head black margined 
with white, while those on the nape are brown. 
Nest. A depression in the sand. 
Eggs. Clutch, one ; sometimes two ; ground-colour dark to light stone, marked with 
blotches and wavy lines of very dark purple, other markings of lavender which 
appear as if beneath the shell ; axis 56, diameter 39. 
Breeding-season. October (Hull) ; November (Campbell) ; January (Mellor). 
Me. H. Stuaet Dove* says, when diving for its food, this bird does not go any 
depth beneath the water, and in some cases only half submerges itself, and 
rises on the wing immediately afterwards. It has a peculiar way of bending 
its head down when on the wing, looking for prey, and this, combined with 
its sharp-pointed beak, gracefully curved wings, and forked tail, render it 
unmistakeable. 
Leggef writes : “ This handsome Tern breeds at the Little Actseon. The 
nests were sHght depressions among shingle, overgrown with herbage, just 
above high water mark, a few herbs and strips of seaweed being the only 
lining in the bottom. 
“ The eggs were two in number. The ground colour varies from pale 
yeUowish-stone to stony-white, and the markings, which are very handsome, 
are hieroglyphic in character, consisting of zigzag and otherwise irregular 
linear blotches, slightly confluent in parts, and laid on over light, inky grey or 
lilac streaks and spottings. They measure from 2.24 to 2.3 inches in length, 
by 1.52 to 1.55 inches in breadth ” : and noted that Hume’s measurements of 
twenty- flve eggs from the Island of Astolah off the Mekra coast gave 2. 3-2. 7 
inches bv 1.63-1.78 inches.” 
%/ 
The same writer J says : “A single example seen near Penguin Island. 
The so-called ‘ Bass Straits ’ Tern, is common in the Derwent from August 
until midsummer. It breeds down the Channel and at the Little Actseon 
Islands, but it is apparently more abundant in the Straits than in the South, 
breeding on many of the islands on the former. I have entered this Tern in 
* Emu, Vol. V., p. 160, 1906. 
t Papers and Proc. Roy. Soc. Tasm. 1887, p. 130, 1888. 
J i6., p. 95 : “ Birds of Maria Island.” 
VOL. II. 
341 
