310 MR. W. H. HUDSON ON THE BURROWING OWL. [May 19, 



though old and dried up as a bit of parchment. This I have often 

 seen them do. Though the Owls are always on familiar terms with 

 the Vizcachas, and occasionally breed in one of their neglected 

 burrows, they generally excavate their own burrows. The kennel is 

 crooked, and varies greatly in length, from 4 to 12 feet. The 

 nest is at the extremity, composed of wool and dry grass, often 

 exclusively of horse-dung. The eggs are five, white, and nearly 

 spherical. After the female has begun laying, the birds continue to 

 carry in dry horse-dung, until the floor of the burrow and a space 

 before it is thickly carpeted with this material. The following 

 spring the loose earth and rubbish is cleared out ; for the same bur- 

 row may serve them two or more years. It is always untidy, but 

 mostly so during the breeding-season and when prey is very abun- 

 dant, the floor and ground about the entrance being often littered 

 with excrements and pellets of hair and bones, wing-cases of 

 beetles, and feathers, hind quarters of frogs in all stages of decay, the 

 great hairy black spiders of the pampas, and remains of half-eaten 

 snakes and other unpleasant creatures they subsist on. But all 

 this carrion about the Owl's disordered house reminds one forcibly 

 of the important part assigned to it in the natural economy. 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 appearing 

 reluctant to enter the burrow ; but for some weeks after learning to 

 fly they make it their refuge from danger. Old and young birds 

 often live four or five months together. I believe nine tenths of the 

 Owls in this country make their own burrows ; but as thay occa- 

 sionally prefer breeding in the forsaken burrows of mammals to 

 mining themselves, it is probable they would almost always observe 

 this last habit did suitable burrows abound. 



I have never seen any complete account of the North-American 

 form of this Owl, but presume its habits are now well known, as all 

 matters connected with science receive so much attention in that 

 country. From such stray notices of the bird as I have met, I learn 

 that it inhabits and invariably breeds in the kennels of the Prairie- 

 Marmot. The small, neat burrows of that mammal must be far 

 better suited to its requirements than the vast ones excavated by the 

 Vizcacha. 



Probably the Burrowing Owl originally acquired the habit af 

 breeding in the earth in open level bare regions ; and when this 

 habit (favourable as it could not but be in such shelterless places) 

 had become ineradicable, a want of suitable burrows would lead it to 

 clean out such old ones as had become half filled with rubbish, to 

 deepen such as were too shallow, and ultimately to excavate new ones. 



In Buenos Ayres the mining instinct varies greatly in individuals. 

 In the birds that breed in Vizcachas' burrows the instinct is doubt- 

 less weak ; they can hardly be said to possess it. 



Some pairs, long mated, only begin their burrows when the 

 breeding-season is already on them ; others make their burrows as 

 early as April — that is, six months before the breeding-season. Gene- 



