108 BIRDS' NESTS 



a stone, with no definite tunnel running to them, 

 although in some cases the bird would scratch an 

 entrance. A typical nest measured seven inches by 

 five inches, and the depth of the bowl was five inches. 

 Then we may mention Bulwer's Petrel {Bulweria 

 columhina), which places its egg under rock fragments 

 or large stones at the foot of cliffs, whilst the Stormy 

 Petrel is especially addicted to nesting in heaps of 

 loose stones. Mention might here also be made of 

 the Little Auk (Mergulus alle), which deposits its soli- 

 tary egg under large stones and rock fragments, but 

 does not, however, make a nest. Taking another 

 example from the same family (Alcidae) of birds, 

 we may instance the Horned Puffin (Fratercula 

 corniculata), a species which breeds in some numbers 

 on Bering Island and the Commander Islands, and 

 which lays its egg between stones or in holes in rocks. 

 Then some of the Owls must be included in the 

 present class of rock-breeders. Perhaps one of the 

 most familiar is the Little Owl {Athene noctua) with its 

 southern representative Athene glaux. These birds 

 often lay their eggs on a scanty nest (usually of food 

 refuse after the manner of their kind) in a rock 

 crevice or beneath a large boulder ; whilst in Algeria, in 

 localities where cliffs are absent, the Southern Little 

 Owl seeks a suitable substitute in the sides of the wells. 

 Mention should also here be made of such species as 

 the Jackdaw and the Starling, which not unfrequently 

 resort to such localities in quest of a nesting site. 



