EXOTIC BIRDS FOR BRITAIN 171 



mountain summits the ptarmigan gets his living. 

 Wagtails run on the clean margins of streams; 

 and littoral birds of many kinds are in possession 

 of the entire sea-coast. Thus, the whole ground 

 appears to be already sufficiently occupied, the 

 habitats of distinct species overlapping each other 

 like the scales on a fish. And when we have 

 enumerated all these, we find that scores of others 

 have been left out. The important fly-catcher; 

 the wren, Nature's diligent little housekeeper, 

 that leaves no dusty corner uncleaned; and the 

 pigeons, that have a purely vegetable diet. The 

 woods and thickets are also ranged by jays, 

 cuckoos, owls, hawks, magpies, butcher-birds — 

 Nature's gamekeepers, with a licence to kill, 

 which, after the manner of game-keepers, they 

 exercise somewhat indiscriminately. Above the 

 earth, the air is peopled by swifts and swallows 

 in the daytime, and by goatsuckers at night. And, 

 as if all these were not enough, the finches are 

 found scattered everywhere, from the most se- 

 cluded spot in nature to the noisy public thorough- 

 fare, and are eaters of most things, from flinty 

 seed to softest caterpillar. This being the state 

 of things, one might imagine that experience and 



