704 PATAGONIAN EXPEDITIONS I ZOOLOGY. 



above the surface, and continuing a minute or longer without altering their 

 position. They do not drop the whole distance at once on their prey, but 

 descend vertically, tumbling and fluttering, as if wounded, to within 10 

 yards of the earth, and then, after hovering a few seconds more, glide 

 obliquely upon it. They prey on every living creature not too large to be 

 overcome by them. Sometimes they sever off and leave untasted the head, 

 tail, and feet of a mouse. The hind quarters of frogs and toads are almost 

 invariably rejected ; and inasmuch as these are the most fleshy and suc- 

 culent parts, this is a strange and unaccountable habit. They make an 

 easy conquest of a snake 18 inches long, and kill it by dealing it blows 

 with the beak, hopping briskly about it all the time, and appearing to 

 guard themselves with the wings. Many individuals become destructive 

 to poultry-yards, carrying off the chickens by day. In seasons of plenty 

 they destroy more prey than they can devour; but in severe winters they 

 come, apparently starving, about the houses, and will then stoop to carry 

 off any dead animal food, 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 burrow may serve them two or more years. It is always 

 untidy, but mostly so during the breeding season, and when prey is very 

 abundant, 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 



