I9I4- Barrington — Bird Rushes and U/fens. 245 
shortest flight across the Channel, which is at least 50 miles, 
compared with the weight of muscular tissue, must be 
extraordinary. 
I have already stated that the word " Wrens," which is 
of common occurrence in the schedules, is used by light - 
keepers to include all the Warbler group, and even Gold- 
crests, so that when drawing conclusions as to the frequency 
of the Wren, I preferred to rely entirely on specimens 
actually received. Because these were so few, and the 
WYen's power of sustained flight apparently so small, it was 
inferred that its cross-channel flights, if they took place at 
all, were of an isolated and exceptional character. However, 
Professor Patten's interesting records from the Tuskar, 
and the ten specimens just received from that station, 
require explanation. 
If the Wren be a regular migrant, how are we to explain 
such local varieties as the St. Kilda Wren, and the Faroese 
Wren, for w^hich isolation for a lengthened period is 
essential ? 
St. Kilda is only 52 miles west of Harris, just about the 
same distance as the Tuskar from Wales. It is true that 
Faroe is over three times that distance from Shetland ; but 
if the Wren be indeed a regular annual migrant, over 50 
miles of the Irish Channel, could it not occasionalty have 
flown to St. Kilda or to Faroe and thereby prevented the 
evolution of racial characters ? 
Are not the Irish Jay, Coal Tit, and Dipper the result of 
isolation and special environment ? There is no evidence 
that those species ever migrate across the Channel, and if 
the British Wren travelled even occasionally to St. Kilda 
and Faroe, would the varieties in these islands be now 
obtainable ? 
In my collection, there are skins of Icelandic, Faroese, 
and St. Kilda Wrens, all of which differ slightly, and even 
the Shetland Wren is, I think, an intermediate link between 
the British and Faroese races. But if this little bird takes 
sea- voyages of fifty miles regularl}/ why do these dis- 
tinctions present themselves ? Can it be that there is 
another solution of the difficulty ? Can it be possible that 
