198 THE MIGRATION OF BRITISH BIRDS 



can be little doubt that a subspecific and eventually a 

 specific distinction would result. We may conclude, 

 therefore, beyond the slightest doubt, that our paucity 

 of endemic species is due to the vast amount of migra- 

 tion taking place over our islands ; and so long as the 

 migration of any and every species continues, so long 

 shall we remain poor in peculiar forms. Of plants, 

 insects, fish, and animals, however, whose means of 

 dispersal are more limited, and whose habits are seden- 

 tary, we have a fair proportion of endemic species — a 

 fact which only emphasizes the truth of the foregoing 

 remarks. 



Let us now pass to the Channel Islands and Heligo- 

 land. So far as the Channel Islands are concerned 

 precisely the same remarks apply — their geographical 

 position preventing the establishment of a single en- 

 demic species. Their avifauna contains a fair proportion 

 of species, composed of residents, summer migrants, 

 winter visitors, and coasting migrants ; yet none of the 

 resident species are isolated from the vast stream of 

 migratory individuals of the same species regularly 

 crossing their area. All the species indigenous to them 

 are continental or British, and none of them are abso- 

 lutely sedentar}-. Heligoland, situated about 40 miles 

 from the mouth of the h^lbe, and only about one-fifth 

 of a square mile in area, is said (on the authority of 

 Herr Giitke) to have been visited by no less than 396 

 species,^ yet not a single endemic bird is found thereon 

 — a fact entirely due to the abundance of migratory 

 birds that so regularly pass over it. 



We will now proceed to notice the various West 

 ' See footnote, p. 190. 



