Introduction 1.3 



the two questions. By distribution we mean, unless it 

 is otherwise stated, the limits within which a species 

 ranges in the breeding season, just as tlie bird's range 

 is, if unqualified, taken to mean its summer range. 

 Even in Britain distribution is often limited, as in the 

 case of the Snow Bunting of the Scottish highlands or 

 the Nightingale of England ; but the range of each 

 species will be found given in detail below, and need 

 not delay us here. Many birds throughout the world 

 are extremely local ; many are only found in deserts, 

 isolated islands, and so forth, while the Red Grouse may 

 be given as the example nearest to our doors, as it is 

 absolutely confined, as a native species, to the United 

 Kingdom. But Britain is a comparatively small area, 

 and it is necessary to survey the whole globe in distri- 

 butional questions. This is far beyond our scope, and 

 we need only state that, taking into consideration birds 

 alone, Dr P. L. Sclater suggested a division of the 

 world into six Regions, the Palsearctic, Ethiopian, Indian, 

 Australian, Nearctic, and Neotropical (see map), in each 

 of which he considered the forms — taken as a whole — 

 to be more closely connected with each other than with 

 those of another Region. The Palaearctic and Nearctic 

 (of the Old and the New Worlds) together form the 

 Holarctic ; New Zealand may be considered separately. 

 If our readers ever proceed from the study of British 

 Birds to that of foreign species, they will be greatly 

 struck by the prevalence of very peculiar forms in 

 certain countries, by the wonders of the Arctic and 

 Antarctic areas, by the marvels of desert and island 

 life, by curious extinct birds, by extraordinary habits 

 of courtship, sexual display, parasitism, and many other 

 subjects, but even within our islands they may spend 



