46 BRITISH BIRDS. [vol. vii. 



in CO. Derry last year that made Mr. Mc William pay 

 increased attention to the subject this summer," we 

 :seem to tread on debateable ground, and ask : Had the 

 birds been breeding in the district during previous 

 years without having been discovered, because 

 Mr. McWilHam, while being " a close and accurate 

 observer," had not given the increased attention to the 

 subject ? Debatable though this point may seem to 

 be, I am nevertheless incUned to lean to the idea that 

 the birds had not long colonized the spot where they 

 were detected, because in regard to the question as 

 to when Tree-Sparrows first appeared on Inishtrahull 

 Island, Mr. Sulman, Chief of Lloyd's Marconi operators, 

 tells me that as far as the dwelUng-houses at the west-end 

 of the Island are concerned, the first pair of "sparrows" 

 of any kind observed was in the spring of 1906, a time 

 which corresponds closely with the discovery of the 

 Tree-Sparrow on the mainland of co. Donegal and in 

 CO, Derry, as well as in co. Mayo. Hence it is not 

 inconceivable that a visitation of immigrants, amounting 

 almost to a small irruption, took place about that period, 

 Inishtrahull being visited more or less synchronously 

 with the above-mentioned localities of the mainland of 

 CO. Donegal and other counties. Such an irruption 

 might simply be an increase in the large numbers which, 

 according to Saunders,* arrive from the Continent on the 

 north-east coast of Britain every autumn, and so numbers 

 of such birds may have spread westward to the coast- 

 lands of Ireland. At any rate the discovery of Tree- 

 Sparrows much about the same time in so many different 

 districts is a matter worthy of note. Returning to the 

 observations of Mr. Sulman, he teUs me that he was first 

 disturbed by the twittering of " sparrows " in the early 

 mornings above his bedroom window in the spring of 1906, 

 and noticed shortly afterwards that the birds had taken 

 up their quarters under the weather-boards of his house, 

 A few weeks later these "sparrows" were observed carrying 



* Saimders, Manual of British Birds, 2nd ed., 1899, p. 181. 



