58 THE ZOOLOGIST. 



regular species. These belong mostly to the Anatidce and 

 Gharadriidce. 



Next in order is the fourth class — the accidental and occa- 

 sional visitors. These amount to 169, but owing to the diffi- 

 culties of observation many of them may undoubtedly be classed 

 as regular spring, autumn, or winter migrants. 



In the same way the numbers of the other classes must be 

 modified according to locality, period, and observation. 



Of the fifth class, only one species — the Great Auk — is ex- 

 emplary. One species — the Little Owl — may also be classed as 

 a lately introduced bird, like the Red-legged Partridge of an 

 earlier date. 



Thus, then, we see how it is possible for the birds on the 

 British list to amount to 415 species, since considerably over 

 one-third are accidental visitors, and barely half of them remain 

 to breed with us. After all, when we consider the fact in all its 

 bearings, it is not so very surprising if we look at it from a 

 world-wide point of view. Our islands are situated in the 

 temperate regions, where birds that live in the warmer regions 

 migrate to breed. We get, then, birds from the semi-tropical 

 regions, and birds on their way to and from the far north from 

 our own region. In a similar way we are situated only a few 

 miles, in the south, from the Continent. This in itself explains 

 why our own avifauna is largely supplemented in the summer by 

 visitors from all parts. Indeed, when we come to think of it, we 

 must wonder why many species abundant on the Continent are 

 not met with at all in our own country. We find birds, such as 

 the Stork, breeding in Holland, which from its nature might just 

 as well breed in England. 



Lastly, it is not surprising that we receive visits from American 

 species, when we consider the long distances travelled by our 

 summer migrants, and the fact that it is only a five days' trip in 

 the liners of the Atlantic to the New World. How comparatively 

 short a distance must it seem, then, to such an untiring creature 

 on the wing as the bird ! 



