WOODLAND MIGRANTS 189 



the subject I have been considering; and this relates 

 to the peculiar conditions of the country where I 

 first observed migration — a sea-like expanse of level 

 grassy plain without a native tree-vegetation except- 

 ing in a few widely separated spots. When these 

 plains, or this one great continuous plain, was settled 

 on by Europeans, they planted groves and orchards 

 around their houses. These small plantations were 

 far apart, scattered about all over the pampas, a 

 purely grazing country, and stood up conspicuously 

 at a great distance like islands of trees on the green 

 sea-like surface of the land. One would suppose 

 such conditions unsuited to woodland species; for 

 the wood is their true home, the only safe place for 

 them, and they naturally fear the wide open flat 

 space, where there is no refuge, no escape, from the 

 ever-present bird of prey on the watch for them. I 

 found that there were, in fact, quite a number of 

 summer visitants to my district that never ventured 

 over the wide open spaces; they came south, but 

 kept strictly to the forest growing on the marshy 

 shores of the Plata river. Anywhere in this forest 

 I could see a dozen or more species any day that were 

 never seen out of it, not even in the plantations within 

 a few miles of the coast, since to get to them they 

 would have to fly across a few miles of treeless country. 

 Nevertheless, the wave of migration brought to 

 us a considerable contingent of woodland species 

 each spring. Doubtless many were night-travellers. 

 Thus, in the seven or eight acres of shade and 

 fruit trees at my home, our spring visitors included 



