FAUNA OF THE MONTE BELLO ISLANDS. 639 
no nest, the single newly-hatched chick lying in a depression in 
the flat rock, into which had been placed a scanty collection of 
grass and sticks as a lining; here there was no danger of the egg 
or young bird falling out and being destroyed. 
The species seems to subsist entirely upon fish and sea-snakes, 
never molesting the sea-birds (at least the adults), though the pair 
upon Trimouille were subject to violent attacks from a pair of 
Ospreys which were nesting upon a neighbouring rock. Whenever 
they were in the air together, the Ospreys would circle above the 
Eagle, screaming loudly, and then suddenly swoop down upon it. 
The latter bird would usually turn sharply sideways or almost 
upon its back, holding out its formidable talons and thus warning 
off its assailants, a feat of balance and flight fascinating to watch, 
24. HALIASTUR GIRRENERA Vieill. 
This species occurs around the coasts of Northern and Eastern 
Australia, and New Guinea. The N.W. Cape and Monte Bello 
Islands are near the southern limit of its distribution on the 
west side of the continent. In the region of the Ashburton 
River it is not uncommon, and two pairs were observed upon the 
Monte Bello Islands, where they seem to subsist almost entirely 
upon small rock-crabs. On Trimouille one of these birds was 
observed to leave a heap of broken limbs and empty carapaces, 
which formed a pile more than a yard across upon a slab of rock in 
a large shallow cave to the east of the island. A nest contain- 
ing similar remains was discovered amongst the mangroves on 
Hermite. It was placed in the fork of a Bruguiera, and was 
deep in form, about equal in size to that of a crow and composed 
of sticks, seaweed and Spinifex, with no distinct lining. It con- 
tained a single egg, dirty white in ground-colour, with scanty and 
minute streaks and sparks of rusty brown. 
25. PANDION HALIAHTUS MELVILLENSIS. 373. Northern White- 
headed Osprey. (PI. IT.) 
Mathews, Austral Avian Record, vol.1. p. 34,1912; Melville I. 
This Western Australian form of the almost cosmopolitan species 
occurs very abundantly, particularly frequenting the archipelago of 
flat rocks and islets lying to the north of the group, upon neariy 
every one of which there was a nest. The majority had laid early in 
June, but fresh eggs were obtained late in July and early in August. 
The nest isa conspicuous and bulky structure, ranging from about 
11 inches to 5 feet in height, but always measuring about 3 ft. 6 in. 
in internal and about 5 feet in external diameter. It is composed 
of sticks, drift-wood, seaweed and bits of coral, etc., the shallow 
cavity being lined with finer seaweeds and any other soft 
material. Only one nest is ever found upon an island, though 
nests may be in close proximity if separated by water. When 
situated upon a low rock, the nest is usually four to five feet high 
and forms a conspicuous object. On the larger islands it is 
