22 Proceedings of the Royal Irish Academy. 



come to Europe without crossing the Atlantic Ocean at all. The circum- 

 stance that a few, such as the American Eobin, seem to have occurred more 

 frequently in eastern Europe than in the west, may imply that they have 

 tiown across Bering Strait to Siberia, thus entering Europe from Asia. 



Altogether no less than sixty-eight species of American birds have been 

 recorded from Europe by ]\Ir. Dalgleish, while only twenty American species 

 are known from Ireland.' The claim of ten of the latter as genuine 

 stragglers from America is considered doubtful, in so far as they may possibly 

 be escaped cage-birds.- A large percentage of the si.xty-eight species have 

 been observed in England ; but even on the small island of Helgoland, near 

 the mouth of the Elbe, twelve species of American birds have been noticed.'' 



From these observations it is evident that the west coast of Ireland is 

 by no means the region wiiere the American bird-visitors first set foot in 

 Europe. Many apparently alight on the Continent of Europe, after com- 

 pleting their perilous voyage across the North Atlantic from Greenland. 

 Othei's liave only Ijeen recorded from Scotland or England. Ireland has not 

 yielded any exceptional number of such records ; and they are not all from 

 the west coast. 



From Mr. Freke's Catalogue we can gather some idea as to the frequency of 

 European bird-visitora to America ; that is to say, of such species as are 

 supposed to have crossed the Atlantic in the opposite direction. Only about 

 one-fourth of the number of American visitors to Europe have made the 

 voyage in the reveree direction, and most of the latter are such species as 

 have been recorded from Greenland or arctic America.' Very few have 

 passed southward into the United States. Mr. Praeger pointed out to me, 

 and I quite concur with liim, tliat the comparatively small number of bird- 

 visitoi-s from Europe to America miglit, to some extent, be due to the fact 

 that the prevailing winds in the North Atlantic from west to east would 

 retard the flight of birds in the opposite direction. 



The fact that both in America and Europe the indigenous species of plants 

 and animals identical to the two continents are largely confined to the coast 

 i-egion may appear at fii-st sight in favour of the theory of introduction by 

 birds. Almost all the American plants, and all the American freshwater 

 sponges at any rate, occur in the Ndcinity of the coast. It has been argued, 

 therefore, that, after their long flight across the ocean, birds would naturally 

 alight on the earliest opportunity ; and that it was for this reason that the 



' Oalglcish, J. J., " North American liirda in Europe." 



' Usaher, K. J., "List of Iri.-h Birdn." 



-* Frcke, I'eny, "Birds found in Europe und North America." 



