180 BIED STUDIES WITH A CAMERA 



shared their underground homes, one bird's nest 

 being at the end of the burrow, tlie other about half 

 way to the entrance. The Petrels also occupied 

 burrows of their own, which, judging from the 

 actions of the birds f(jund 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 tiie surface of the water. Two of 



>m- 







■Set. 



11.'). lA'jleli's I'ctiL'l on Must at und ni' i',\(.'a\ atcil Ijilil'tw. 



the eight or ten Petrols" 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 Kittiwako. The remaining nests 



