16 The Bird Rock Group. 
family Alcidz, a group of sea-birds found only in the North 
Atlantic and North Pacific. (Several allied species may be found 
in the general collection of North American Birds, see gallery, 
Case A.) Everywhere they are island-nesting birds, indeed some 
of the largest bird islands in northern seas are inhabited almost 
entirely by Murres:—the Farne Islands off the eastern coast of 
northern England, the Farallones at the entrance of San Francisco 
COMMON MURRE AND EQQ. 
From the Group. 
Bay, and St. Paul Island in Bering Sea, are tenanted by countless 
individuals of these birds. Murres feed on fish, which they se- 
cure by diving, using both wings and feet in propelling themselves 
while under water. Their note isa hoarse call sounding somewhat 
like the syllable murve, whence their common name. They make 
no nest, but lay their one peculiarly shaped and colored egg on an 
exposed ledge of rock or in a similarly unprotected place. The 
shape of the egg is supposed to be an adaptation to the require- 
oD 
ments of the nesting sites, from which a more elliptical or spheri- 
