INTEODUCTION. IX 



ferent years), Otis macqueeni (1), Anser ruficollis {12), 

 Tadorna rutila (8), Histrionicus torquaius (7 or 8), and 

 Somateria stelleri (2). Of these, as might perhaps be ex- 

 pected, the majority are small insessorial birds which, 

 travelling overland by short stages, would have less difficulty 

 in reaching our shores than if they had to contend with the 

 winds and storms which sweep a vast expanse of ocean. It 

 should, however, be remarked that although a larger number 

 of insessorial birds (8) have occurred less frequently, a 

 smaller number of natatorial birds (4) have occurred a 

 greater number of times. From what we know of the habits 

 of these, they would appear to be, with one exception, fresh- 

 water species (that is, frequenting inland lakes and estuaries), 

 and therefore likely to travel hither by an overland route. 



There is of course a difficulty in relying too strongly upon 

 statistics of this kind, from the fact that few species are 

 strictly confined to the country which they are said to inhabit. 

 In mauy cases the most that can be said is, that a species is 

 more numerous in one particular country than in any other ; 

 and this is the test which has been applied in determining 

 the habitat of the rare and accidental visitants which are in- 

 cluded in Part 11. of this Handbook. Bearing this in 

 mind, the classification of a species as Asiatic — for example 

 S. stelleri, which is also found, though less frequently, in the 

 northern parts of Europe and America (p. 164) — is really less 

 arbitrary than at first sight might appear to be the case. 



The species which have visited us from Africa, eleven in 

 number, are : — Pycnonotus capensis (1), A'edon galactodes (2), 

 Cuculus glandarius (2), Caprimulgus ruficollis (1), Perdix 

 petrosa (4 or 5, but doubtfully true immigrants), Cursorius 

 gallicus (19), Grus virgo (1), G. pavonina (1), Ardea comata 

 (21), A. russata (3), and Plectropterus gambensis (4). Here 

 it will be observed the grallatorial birds are in the majority ; 



