THE BIRDS OF FAIR ISLE 131 



though with difficulty, for it was extremely wild. It 

 proved to be a male, and its stomach contained a 

 Phalangid, two Lepidopterous larvae, and the remains of 

 various Dipterous insects. At first this bird was 

 thought to be new to the British avifauna, but I 

 afterwards found that the Warbler recorded for Sule 

 Skerry as P- viridanus belonged to this species. The 

 Northern Willow- Warbler does not appear to have 

 occurred since in the British Islands, and has only 

 once, I believe, been obtained elsewhere in Western 

 Europe, namely, at Heligoland, on 6th October 

 1854. The bird, however, is a summer visitor to 

 Finmark, Northern Russia, and Siberia, but does not 

 seem to have any winter quarters in the western portion 

 of the Old World, its cold-weather retreats being 

 confined to Southern Asia. 



PiiYLLOSCOPUS ABiETiNA, Northern Chiffchaff. 



Chiffchaffs appear on their passages regularly in 

 both spring and autumn, and belong to this large and 

 long -winged race^ which, among other Northern 

 European countries, summers in Scandinavia, to and 

 from which, no doubt, the visitors to Fair Isle are 

 travelling. A number of specimens have been obtained 

 whose wing measurements are as follows : — Males, from 

 62 to 64 mm. ; females, from 56 to 64 mm. 



The earliest of the spring migrants was killed at the 

 lantern of the South Lighthouse on 7th May, and the 

 passage northwards has been observed as late as ist 

 June, the main period being from 13th to 20th May. 



Its appearances in autumn are rather late, the 

 earliest date being 26th September, from which date 

 down to 24th October it has occurred at intervals. 



' Phylloscopus collybita abietina. 



