Birds of Heligo la nd. 31 



386. COLYMBUS GLACIALIS. 



Frequent. 



387. CoLYMBUS ARCTICUS. 



Frequent in winter. 



388. CoLYMBUS SEPTENTRIONALIS. 



Common^ except in summer. 



389. UrIA TROILE. 



Common. Breeds on the island. 



390. Uria ringvia. 

 Frequent. 



391. Uria bruennichi. 

 One shot many years ago. 



392. Uria grylle. 

 Frequent in autumn and winter. 



393. Uria mandti. 



An example shot in summer is supposed to belong to this 

 species. 



394. Alca tori>a. 

 Common ; a few breed. 



395. Mergulus alle. 



Winter visitor^ sometimes in some numbers. 



396. Fratercula auctica. 



Occasional visitor; formerly bred on the island. 



Herr Gatke's list would thus appear to make the number of 

 species which have occurred on Heligoland rather greater 

 than that of the recognized British birds, but an examination 

 of the details shows that this Avould be by no means an 

 accurate statement of the case. 



Gatke's list includes more than forty species recognized 

 upon evidence which would not entitle them to admission 

 were the list made np on the same lines as the British list. 

 A few birds are admitted on the authority of skins, of which 

 the evidence that they were shot on Heligoland is not con- 

 clnsivo. Others are allowed to stand though the examples 



