54 STUDIES IN BIRD-MIGRATION 



had a peculiar charm for ornithologists ; but to the 

 student of bird-migration, their irregular, and in many 

 instances presumably erratic visits, are the very reverse 

 of helpful in connection with his researches. The 

 appearance of Central, Eastern, and Southern European 

 species far beyond their wonted homes, and quite off 

 their regular accustomed lines of flight during migration, 

 is distracting, and presents problems which do not admit 

 of satisfactory explanation. All that we can opine is 

 that such occurrences are possibly due to some un- 

 accountable failure of that special faculty already 

 alluded to, possessed by migratory birds, which leads 

 them unconsciously to the particular seasonal haunts 

 they should seek. The stimulus to migrate has certainly 

 been strong within the wanderers, or many of them 

 would never have reached such a far-off goal as 

 Fair Isle. 



The following species obtained at Fair Isle are new 

 to British fauna : — Pine Bunting, Thrush-Nightingale, 

 Northern Willow- Warbler, Blyth's Reed- Warbler, and 

 Red-rumped Swallow. Among the other birds of ex- 

 treme rarity as visitors to the British Isles are the 

 Black-throated Wheatear, Subalpine Warbler, Siberian 

 Chiff-chaff, Lanceolated Grasshopper- Warbler, Savi's 

 Warbler, Red-throated Pipit, Greenland Redpoll, Black- 

 headed Bunting, Rustic Bunting, Yellowshank, etc. 



The discovery of the regular occurrence of such former 

 rarities as the Yellow-browed Warbler, Red-spotted 

 Bluethroat, Little Bunting, Ortolan, and Grey-headed 

 Wagtail, and the not infrequent visits to Fair Isle of 

 other species which were once supposed to be quite 

 irregular in their appearance in the British Islands, has 

 resulted in the necessity for their status as British 



