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ON THE DISTRIBUTION OF SOME BIRDS OB- 

 SERVED IN IRELAND AND IN SWITZERLAND. 



By Charles J. Patten, B.A., M.D. (Chief Demonstrator in 

 Anatomy, Dublin University), and W. J. Williams. 



That the large majority of birds are widely distributed over 

 the face of the globe is a fact now well ascertained. Their 

 migratory propensities, which seem to be the rule rather than 

 the exception, account largely for their geographical distribution. 

 But it does not necessarily follow from this that certain species 

 are equally plentiful in different countries ; for example, the Red- 

 start is decidedly rare in Ireland, whereas in many parts of the 

 Continent it is quite a plentiful bird. Even in the same country 

 a bird may be common in one province, and unknown in another. 

 Thus, in Kilkenny and Queen 'sCounty the Jay is often seen, 

 whereas it is practically absent from Louth and Dublin. 



These facts concerning distribution are highly important to 

 those who may wish to determine the absolute rarity of birds, a 

 matter which every collector should consider before attempting 

 to diminish their numbers. A non-breeding casual migratory 

 species, seldom occurring in the British Isles, but common and 

 widely distributed in other countries, cannot in any sense be con- 

 sidered a really rare bird. It is only relatively so, and in the 

 cause of science it seems quite allowable to capture such a 

 species provided that the scientist wishes to advance his know- 

 ledge of ornithology. By such a procedure he will not materially 

 lessen the numbers of the species, and moreover he will obtain 

 reliable evidence of the occurrence of a so-called rare native bird. 

 The present article has been written with the view of supporting 

 this idea. The occurrences of different kinds of birds (as many 

 as possible) inhabiting both Ireland and Switzerland are in the 

 first place recorded. Their variation in numbers in the two 

 countries (the question of relative rarity) is then compared. But 

 in all cases one must not expect the numbers to sensibly vary. 



