BANK-MARTIN 39 



laria) have everywhere afforded the Martins abun- 

 dance of breeding-places on the plains, even where 

 there are no streams or other irregularities in the 

 smooth surface of the earth. 



The Minera bores its hole in the sides of the 

 Vizcacha's great burrow, and in this burrow within 

 a burrow the Martin lays its eggs and rears its young, 

 and is the guest of the Vizcacha and as much depen- 

 dent on it as the House- Wren and the Domestic 

 Swallow on man ; so that in spring, when this 

 species returns to the plains, it is in the villages of 

 the Vizcachas that we see them. There they live and 

 spend the day, sporting about the burrows, just as 

 the Common Swallow does about our houses ; and 

 to a stranger on the pampas one of these villages, 

 with its incongruous bird and mammalian inhabi- 

 tants, must seem a very curious sight in the evening. 

 Before sunset the old male Vizcachas come forth to 

 sit gravely at the mouths of their great burrows. 

 One or two couples of Mineras, their little brown 

 bird-tenants, are always seen running about on the 

 bare ground round the holes, resting at intervals 

 with their tails slowly moving up and down, and 

 occasionally trilling out their shrill laughter-like cry. 

 Often a pair of Burrowing-Owls also live in the 

 village, occupying one of the lesser disused burrows ; 

 and round them all flit half a dozen little Martins, 

 like twilight moths with long black wings. It is 

 never quite a happy family, however, for the Owls 

 always hiss and snap at the Vizcacha if he comes 

 too near ; while the little Martins never become 



