126 A HISTORY OF BIRDS 



during the breeding season. In the case of aquatic birds 

 which have perforce to congregate in great numbers on a small 

 area of land, this phase is presented in a very striking manner. 

 Moseley cites a case of this kind, where, when visiting Night- 

 ingale Island — one of the Tristan Da Cunha group — he found 

 vast numbers of Penguins {CatarrJiactes chrysocouie) and Yellow- 

 billed Albatrosses {Dioinedea cubninata) breeding together on 

 the open ground, and with these were many nestling pairs of 

 Skuas {Stercorarins autarcticus), while the soil beneath was 

 riddled with holes burrowed by various species of Petrels. 



Similarly, the huge nests of large birds of prey, such as 

 those of the Secretary-bird {Serpentarius) and of the Osprey 

 {Pandion\ invariably lodge within their walls numbers of nests 

 of small Passerine birds — and even Night-herons in the case of 

 the Osprey — these nests being built into the outer walls, much 

 as birds build nests in the thatched roofs of houses. This 

 peculiar site is chosen, however, not so much for convenience 

 as for the sake of freedom from molestation which they gain 

 by thus seeking the protection of their powerful neighbours. 

 Similarly, in France the Chaffinch is said to build its nest, 

 whenever possible, as near as may be to that of the Missel- 

 thrush, a bird which is exceedingly pugnacious and intolerant 

 of the presence of Magpies which have rather a fondness for the 

 eggs of small birds. 



But instances of this kind could be multiplied with ease. 

 Let as pass on to stranger associations. One of the most 

 familiar examples of the kind to which we refer is that 

 afforded by the Burrowing Owl {Speotyto) of America. In 

 North America this bird shares the burrows of " prairie-dogs," 

 rats, ground-squirrels or badgers, and in South America those 

 of the Viscacha, Patagonian hare, and, it is said, even of 

 armadillos and large lizards, constructing therein a nest of 

 grass and feathers. Where ready-made burrows are not to be 

 had, however, they will dig for themselves. Similarly, various 

 species of Petrels in New Zealand share the burrows of the 

 " Tuatera Lizard " (Sphenodon). The Petrel seems generally 

 to live on the left, the Tuatera on the right side of the burrow ! 



The amicable terms which these birds seem to have es- 

 tablished with the occupants of these burrows is the more 

 striking because the British Puffin which, whenever possible, 



