176 THE MIGRATIONS OF BIRDS 



in South America or elsewhere. Eggs of yellow-legs 

 are said to have been found in Argentina, and Lay- 

 ard has stated that in New Caledonia he has seen 

 the golden plover followed by a downy chick; but 

 in these and similar instances on record supposed 

 parentage on the part of the shore-birds concerned 

 has been based solely on assumption and associa- 

 tion, and authentic instances have never been pro- 

 duced. Layard, for example, did not collect the 

 downy young that he supposed to be that of a golden 

 plover; and eggs have been attributed to the yel- 

 low-legs in Argentina simply because those birds 

 were seen near-by. 



Double nesting periods have been claimed for the 

 European bee-eater and some other birds in South 

 Africa, but as our knowledge has increased, it ap- 

 pears that, with the possible exception of certain 

 cuckoos, the birds that breed in Africa are a dif- 

 ferent set of individuals from those that nest in the 

 north. In the New World the pied-billed grebe, the 

 cinnamon teal, and the fulvous tree-duck have 

 breeding ranges in both North and South America. 

 In some cases individuals in the two groups differ 

 slightly from one another, while in others, notably 

 the cinnamon teal, they appear indistinguishable. 

 Yet, so far as we know, the colonies are wholly dis- 

 tinct and have no interchange of individuals. 



There are a number of shore-birds that remain in 



