23 GEOGRAPHICAL DISTRIBUTION 



three next more locally, and it is supposed that the sixth occasionally 



does so : — 



Certhia fumiliaris. 



Anas boschas. 



Anas strepera. 



Pandion Ji all actus. 



Procellaria leachi. 



Podiceps cornutus. 



Podiceps rubricolUs . 



Atithus splnoletta. 



The breeding- range of the three following species is not only subarctic 

 and subtropic, but is also tropic. The first-mentioned breeds commonly 

 within the limits of the British Islands, the next used locally to do so in 

 small numbers, but the last has not been found breeding on our coasts: — 



AIuco flainmeus. 

 Sterna douyaUi. 

 Sterna caspia. 



The breeding-range of one species may be regarded as subtropic and 

 tropic — 



Ardea oiycticorax. 



Eleven species may be regarded as circumtropic. They are oceanic birds 

 which breed on islands M'ithin the tropics, and are of course only accidental 

 visitors of more or less frequent occurrence to our Islands : — 



(Estrelata h(Esitata. 

 QLstrelata torquata. 

 Bulweria columbina. 

 Puffinus major. 

 Pnffinus griseus. 

 Pi(ffinus obscurus. 

 Daption capense. 

 Oceanites ivihoni. 

 Anoiis stolidus. 

 Sterna fuliginosa. 

 Sterna anastlieta. 



Nearly Circumpolar Species. 



Four species of birds which are included in the British List are more 

 than Paliearctic in their breeding-range, but are not quite circumpolar. 

 The three first named breed regularly in the British Islands, and the last 

 is said to have done so : — 



