THE ARGENTINE FRONTIER 353 



empty into the river during the wet months; but now (No- 

 vember) their covu-ses were dry and parched. 



Birds were plentiful, but the species varied little from 

 those typical of the uplands. However, they were nesting 

 and this circumstance furnished a new and interesting field 

 for study. 



One of our first walks took us to an old mill, fallen into 

 decay through neglect. There were hundreds of dollars' 

 worth of machinery ruined through lack of care and the 

 use of improper lubricants. I have frequently seen ma- 

 chinery of various kinds, ranging from typewriters and 

 sewing-machines to Pelton wheels, seriously damaged be- 

 cause lard or tallow had been used instead of oil, and the 

 wearing surfaces never cleaned. In one of the dust chutes 

 a pair of chestnut flycatchers (Hirundinea) had built a 

 flimsy nest of twigs and feathers. It contained two cream- 

 colored eggs speckled with red. The birds remained in 

 the vicinity aU'day long and paid no attention to the In- 

 dians working near by, but when a dog chanced to pass 

 they darted at it furiously, making quick dashes at its head 

 and snapping their bills with a loud, popping noise. An- 

 other pair of birds of the same species had a nest above 

 the door of a near-by house. 



Leaf-cutting finches also called tooth-billed finches 

 (Phytotoma), were very abundant. The inhabitants de- 

 stroyed them whenever possible, as the birds cut the blos- 

 soms off the fruit-trees and grape-vines. The bright, 

 saffron-breasted male sat in the top of some thorny bush 

 and uttered queer, immusical wails that reminded us of the 

 mewing of a forlorn alley cat, while his gray-and-black- 

 striped mate incubated the eggs in a small but compact 

 nest hidden farther down among the spine-armed branches. 

 We examined numbers of the nests; each one contained 

 three eggs of a deep-green color, marked with a few black 

 lines about the large end. 



Oven-birds built their dome-shaped mud nests on fence- 

 posts or the larger branches of the few poplar-trees that 



