THE BIRDS OF HELIGOLAND 427 



the stems of large forest trees ; their feet are indeed feeble, but 

 provided with large curved claws, and the feathers of their tail are 

 stiff and pointed. All these parts nevertheless entirely differ hi 

 structure from the corresponding parts in the Picidse. 



230. Tree Creeper [BAUMLAUFEK]. 

 CERTHIA FAMILIARIS, Linn. 



Heligolandish : Boam-Looper = Tree-runner (lit.). 



Certhia familiaris. Nauinann, v. 398. 



Common Creeper. Dresser, iii. 195. 



Grimpereau familier. Ternminck, Manuel, i. 410, iii. 288. 



This small harmless bird visits Heligoland in limited numbers 

 only ; it is more frequently seen in autumn than in spring, but in 

 all cases it is only scattered and solitary individuals that one ever 

 meets with, climbing about in the few insignificant trees and among 

 the shrubs of the island. 



The nesting area of this species extends from Portugal to 

 Japan, as well as throughout the whole of North America; its 

 latitudinal range extends from north Africa to above 62 N. latitude 

 in Sweden. 



Swift Cypselus. The two species of this genus resident in 

 Europe are also included in the bird-list of Heligoland, although 

 one of them can only be noted as occurring in extremely isolated 

 instances. Members of this genus are found in all parts of the 

 world, though Asia appears to possess the largest number ; Jerdon 

 gives eight for India, including therein three very closely related 

 Acanthyllis species, as well as the two European ones. It is singu- 

 lar that of the Asiatic Swifts only one has hitherto been met with in 

 Europe viz. Acanthyllis caudacuta, which has been shot in Eng- 

 land on two occasions, viz. in July 1846 and again in July 1879. 

 The spring migration of the latter year was so rich in rare visitors 

 from the far East or South-east that I advised my English ornitho- 

 logical friends to keep a good look-out ; and the Swift in question, 

 whose breeding range extends from eastern Asia southward to 

 Australia, shows how seasonable my recommendation was in this 

 instance. The separate genus Acanthyllis is distinguished from 

 Cypselus by the fact that only three instead of all four of its toes are 

 directed forwards, and by the quills of its tail-feathers being pro- 

 longed to hard points. 



