180 BIRD STUDIES WITH A CAMERA 
shared their underground homes, one bird’s nest 
being at the end of the burrow, the other about half 
way to the entrance. The Petrels also occupied 
burrows of their own, which, judging from the 
actions of the birds found in them, they had exca- 
vated by the aid of their toes.” 
The Petrel’s nests were composed of fine grasses 
and a few feathers, and one nest contained two bits 
of white birch bark, the presence of which raised 
the question as to whether these gleaners of the sea 
do not gather suitable nesting material when they 
find it floating on the surface of the water. Two of 
95. Leach’s Petrel on nest at end of excavated burrow. 
the eight or ten Petrels’ nests examined contained a 
single white egg; one egg constituting a full set 
with this species, as with all the other rock-nesting 
birds, except the Kittiwake. The remaining nests 
