LIFE (3N PELICAN ISLAND, WITH SOME SPECULA- 

 TIONS ON THE ORIGIN OP BIRD MIGRATION 



"*■ iHE study of isolated colonies of 



birds, particularly of those situ- 



'i ated on islands, throws much light 



on several as yet little-understood 



problems of bird migration. 



With mainland birds of general 

 distribution — the Robin, for exam- 

 ple — the individual is, except when nesting, lost in 

 the species, and unless the bird be jieculiarly 

 marked who can say whether the Robins which 

 nest with us one year are the same as those of 

 the preceding season — where our summer Robins 

 winter, or our winter Robins summer ? and who can 

 tell whether the first Robins to come in the spring 

 are our summer resilient birds, or early migrants 

 en i-oufe to more northern nesting grounds ? 



In the case of certain island-inhabiting birds, 

 however, sinne of these questions may Ije answered 

 with a fair degree of certainty. Thus Ipswich Spar- 

 rows are known to nest only on Sable Island, off the 

 Nova Scotia coast, and we are warranted in believ- 

 ing that the same birds, fate permitting, return to 

 their sandy home year after year. Clannets {Sula 

 hassan(t) nest in the western hemis])here only on 

 three islets in the Gulf of St. Lawrence, and it is 



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