REPRODUCTION— NIDIFI CATION 175 



dark recesses of caves or the deserted burrows of other animals. 

 Not finding these in all cases sufficiently roomy, they naturally 

 enlarged the end of the burrow which was to form the brooding 

 chamber, and thus they acquired the first lessons in excavation, 

 to be turned to account when no ready-made burrows were to 

 be found. 



A survey of the various types of living birds will show that 

 in nearly every group some select either burrows or caves for 

 the work of incubation. Thus one of the " Rock-hopper" Pen- 

 guins ( Catarrhactes chrysocome) in K erguelen's Land nests in caves, 

 though in Prince Edward Island it must be remarked they 

 breed in the open, laying a single egg on a small heap of stones. 

 The Magellan "Jackass" Penguin {Spheniscus magellanicus) 

 digs large and deep burrows in the peat banks by the sea, often 

 constructing one large chamber to serve for several pairs of 

 birds ; and similarly the little Blue Penguins of the Genus Endy- 

 ptula breeds in dark recesses of caves. All the Petrels, save the 

 Albatrosses and the Giant Ydtx€is,{Pssifiagagigantea),\)\xi\.6. either 

 in deep crevices or in burrows, though but the merest apology 

 for a nest is ever made, and this may be wanting. The Tropic- 

 birds {PJuEthori) nests in holes in cliffs, eg., P. rubricauda, or, 

 when these are wanting, in holes in trees, eg., P. fulus. 

 Among the Anserine birds we find the Golden-eye duck {Clan- 

 gula glaucion) breeding in holes in trees, and the Sheld-ducks 

 (Tadomd) in burrows, usually those excavated by rabbits. But 

 these birds will also, when ready-made holes are wanting, dig for 

 themselves. Where rabbit-burrows are used it appears to be a 

 common practice to lengthen the tunnel leading to the brood 

 chamber, and in one instance this was found nearly sixteen feet 

 from the entrance, and seven feet below the surface! The 

 Puffins again, among the Auk-tribe, breed in rabbit-burrows, or 

 in burrows of their own making, or in crevices of rocks. Where 

 rabbit-burrows are to be had they will not scruple to eject the 

 rightful owners should there be no deserted tenements in the 

 neighourhood. Among the Pigeons we find the Rock-dove 

 breeding in caves or deep fissures, and the Stock-dove in-rabbit- 

 burrows, or holes in trees, and also in deserted squirrel '• dreys," 

 or thick ivy on old walls. The Parrots all breed in holes, save 

 only the Quaker-parrot {Myopsittacus monachus), which builds a 

 nest of sticks, a huge pile, containing a central chamber, so that 



