BURROWING-OWL 41 



but mostly so during the breeding-season, when 

 prey is very abundant, the floor and ground about 

 the entrance being often littered with castings, green 

 beetle-shells, pellets of hair and bones, feathers of 

 birds, hind quarters of frogs in all stages of decay, 

 great hairy spiders (Mygale), remains of half-eaten 

 snakes, and other unpleasant creatures that they 

 subsist on. But all this carrion about the little Owl's 

 disordered house reminds one forcibly of the im- 

 portant part the bird plays in the economy of nature. 

 The young birds ascend to the entrance of the burrow 

 to bask in the sun and receive the food their parents 

 bring; when approached they become irritated, 

 snapping with their beaks, and retreat reluctantly 

 into the hole ; and for some weeks after leaving it 

 they make it a refuge from danger. Old and young 

 birds sometimes live together for fotu: or five months. 

 I believe that nine-tenths of the Owls on the pampas 

 make their own burrows, but as they occasionally 

 take possession of the forsaken holes of mammals to 

 breed in, it is probable that they would always 

 observe this last habit if suitable holes abounded, 

 as on the North American prairies inhabited by the 

 marmot. Probably our Burrowing-Owl originally 

 acquired the habit of breeding in the ground in the 

 open level regions it frequented ; and when this 

 habit (favourable as it must have been in such un- 

 sheltered situations) had become ineradicable, a want 

 of suitable burrows would lead it to clean out such 

 old ones as had become choked up with rubbish, 

 to deepen such as were too shallow, and ultimately 



