THE CHACO 391 



rats had their runways crisscrossing in every direction — 

 sometimes neat, rounded tunnels with the bottom just 

 under water, and again, wide trails where the vegetation 

 had been trampled down. They look like very large musk- 

 rats and their skins, known commercially as nutria, are ex- 

 ported by hundreds of thousands each year to be manu- 

 factured into felt hats of the better quality. We caught 

 several that gnawed down all the stalks within reach and 

 piled them into neat islands on which to sit. They feigned 

 death until touched with a stick when they attempted to 

 bite and fought viciously. Jumping mice and large, light- 

 brown, woolly rats used the same paths as their bigger rela- 

 tives. One afternoon a fine individual of the great red wolf 

 we had secured at Corumba appeared at the edge of the 

 rushes for a moment only to vanish into the dark marsh 

 at our first movement; a few minutes later he was seen 

 loping into the brush several hundreds of yards away. 



Ducks came to the region daily, mostly teals and rosy- 

 bills, but in small numbers only. They were hard to get, 

 as wading in the waist-deep, ice-cold water and mud was 

 slow work and they invariably took warning and left while 

 still out of range. At night flocks of painted snipe (Rostra- 

 tula) ventured to the open borders to feed. While we were 

 quietly waiting, a dusky form appeared and began to probe 

 the mud frantically, to be joined by others in a short time. 

 They skipped about on the flats adjoining the reed-beds in a 

 most erratic manner, reminding one of the actions of water- 

 beetles, and upon the first sign of danger promptly disap- 

 peared in the labyrinth of stems and grasses. They seldom 

 took wing, and then it was but to flutter up above the tallest 

 reeds and immediately drop out of sight in the thick cover. 



It is to this region of dense totara marshes that the cow- 

 birds revert to spend the winter season, arriving from all 

 directions in comparatively small flocks, but increasing in 

 numbers until there are tens of thousands. 



As the rice was ripening about this time, the birds did an 

 enormous amount of damage. All day long, men on horse- 



