AVES STRIGID^. 705 



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 they occasionally 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 con- 

 nected 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 invari- 

 ably breeds in the kennels of the prairie-marmot. The small, neat bur- 

 rows of that mammal must be far better suited to its requirements than 

 the vast ones excavated by Vizcacha. 



"Probably the burrowing owl originally acquired the habit of breeding 

 in the earth in open level bare regions ; and when this habit (favourable 

 as it could 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 doubtless 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. Generally both birds 

 work, one standing by and regarding operations with an aspect of grave 

 interest, and taking its place in the burrows when the other retires ; but 

 sometimes the female makes the kennel without any assistance from her 

 partner. Some pairs work expeditiously, and their burrows are deep and 

 neatly made ; others go about their task in a perfunctory manner, and 

 begin and immediately abandon perhaps half a dozen burrows, and then 

 rest two or three weeks from their unprofitable labours. But, whether 

 industrious or indolent, by September they all have their burrows made. 



"Most, if not all, the writers who have mentioned our bird err in 

 speaking of its burrowing habits. Azara was perhaps the first to say that 

 it never constructs its own habitations. Molina (usually judicious) flies to 

 the opposite extreme, and asserts, on the authority of P. Fuielle, that it 



