200 THE MIGRATIONS OF BIRDS 



across the Caribbean to northern South America, 

 and then on southward to its principal wintering 

 ground in the central portion of that continent. 

 During winter it continues to frequent swamps and 

 grass-grown marshes, and seems to have its centre 

 of abundance in the Chaco, a vast area of poorly 

 drained, swampy land, with broad grass-grown 

 savannas, that extends west of the Parana and 

 Paraguay rivers, from northern Santa Fe in north 

 central Argentina, north into Bolivia and Brazil. 

 For untold years the bobolink had been safe in this 

 winter home, as for human neighbors it had only 

 scattered groups of Indians of nomadic habit who, 

 though they probably killed a few of these birds 

 with throw-sticks or other weapons, did not trouble 

 to exert themselves particularly after such small 

 game, and were too few in number to be any serious 

 menace. Within the past ten years there has begun 

 a change in this condition, which is bound to affect 

 the bobolink sooner or later. Soil in the Chaco is 

 fertile, and white men, who entered it first to obtain 

 the valuable woods of its forests, have now begun to 

 divide the land and put it under cultivation. Since 

 the World War, colonization has been especially 

 active, and great areas are now settled where a few 

 years ago the only human inhabitants were a few 

 Indians. Sadly enough it must be recorded that 

 the cultivation of rice has begun in this area, and 



