102 BIRDS' NESTS 



From nests made in burrows we may conveniently 

 pass to a consideration of those which are concealed 

 in caves. The number of species that breed in caves 

 is not very great comparatively speaking, and of those 

 not a few make use of other situations as well. Of 

 the species that occasionally make use of caves for 

 nesting purposes one of the most familiar is the 

 Jackdaw (Corvus monednla). The nest of this bird is 

 often a huge pile of sticks wedged into some crevice 

 of the rocks in a cave. At the apex of this pillar or 

 heap of sticks a nest of dry grass, moss, dead leaves, 

 and straws, lined with fur, wool, and feathers, is 

 formed. Another, but in our country unfortunately 

 now much less common, cave dweller is the Chough 

 {Pyrrhocorax gracuhis). This species again is by no 

 means confined to caves for nesting purposes, for it 

 selects holes in cliffs or ruins as well. When the nest 

 is made in a cave some fissure in the sides or roof is 

 selected. This nest is made externally of sticks, 

 branches of heather, and stalks of plants, and the 

 cup containing the eggs is formed of dry grass, roots, 

 wool, fur and occasionally hair. The structure varies 

 a good deal in bulk, according to the size of the site 

 selected, the birds evidently liking to cram as much 

 material into the fissure as it will conveniently hold. 

 The Rock Dove {Columha livia) is a much more per- 

 sistent cave haunter, always selecting such a spot for 

 nesting duties if such be available. Colonies of this 

 Dove, varying in size according to the amount of 



