376 IN THE WILDS OF SOUTH AMERICA 



entirely through; the latter were not occupied. Apparently- 

 whatever birds had drilled the cavities, frequently surprised 

 themselves by emerging suddenly into the daylight they 

 were trying to get away from, at the far end of the burrow. 

 However, not to be discouraged, repeated other attempts 

 were made, some of which were successful as the walls varied 

 in thickness. A small, flat nest of sticks lined with a few 

 feathers comprised the bay-wing's domicile. Some of them 

 contained young birds, and one had five eggs in it. The 

 adult birds always remained in a flock in the vicinity and 

 kept up a shrill screaming while we were near. 



Large, blackish rails inhabited the reedy marshes; they 

 came in flocks to feed in the velvety green islands inter- 

 spersed among the weed and water covered areas. Watch- 

 ing from a concealed position, we could see them strut un- 

 concernedly about, flicking their tails over their backs and 

 jerking their necks and picking up the tiny mollusks and 

 insects that were so abundant. When alarmed they craned 

 their necks, looked about inquisitively, then gave a few 

 hoarse cackles and ran into the weeds; within a few mo- 

 ments they returned, one at a time, and at first slowly and 

 cautiously; but soon, forgetting that danger might lurk 

 near by, they i-ushed for the spots where food was most 

 abundant. Rails are pecuhar and interesting birds. The 

 body is narrow and compressed like a flea's; this enables 

 them to slip through the dense reeds and water-plants in 

 which they live. The comparatively long bills make it 

 possible for them to pick up food in shallow water. Their 

 long, slender toes, giving the feet a wide spread, make walk- 

 ing on floating vegetation and soft mud easy; neverthe- 

 less, at least some species are good swimmers. 



Flocks of night-herons spent the days in a small clump 

 of willows fringing the marsh. At dusk they grew very 

 active and we could hear them croaking from afar. They 

 are splendid eating. 



As at Pulqu^ and the Pilcomayo, birds were hard pressed 

 for nesting-sites. Giant club-cacti apparently were at a 



