20 The Bird Rock Group. 
(See especially in this connection the skin, skeleton, and cast of 
the egg of the Great Auk in the Main Bird-Hall.) 
The Razor-bill breeds from the Bird Rocks and British Isl- 
ands northward and in winter is found as far south as Long Island 
and the Mediterranean. 
KITTIWAKE GULL ON NEST. 
From the Group. 
Kittiwake Gull (2’ssa tridactyla), From six to eight hun- 
dred Kittiwake Gulls nest on Bird Rock. They place their nests 
of sea-weed on the less accessible ledges and doubtless for this 
reason are less preyed upon by man than are the Murres. Kitti- 
wakes are the only birds on the Rock which lay more than one 
egg; their nests containing two or three. The young are born 
covered with down, and during their first winter differ from 
adults in having the tip of the tail and hind neck black. The 
birds of this species feed on fish and drink salt water in prefer- 
ence to fresh. Their name is derived from their singular call, 
