JA2 Barrows o?! Birds of the Lozver Uruguay. [July 



tainly is not for the purpose of catching insects, which are taken 

 in the ordinary manner. 



A nest found October 2, iSSo, contained two fresh eggs, prob- 

 ably an incomplete set. They were white, with heavy brown 

 spots scattered sparsely over the larger ends. The nest was 

 neatly hidden in a wet tussock on the edge of a swamp. It was 

 very deeply hollowed, formed of fine grass and a little hair and 

 feathers, and the lip or border was covered with green moss. 



The species was met with at all points visited, but south of 

 Azul not a single male in the black plumage was seen, though 

 the brown birds (presumably females or young) were met with 

 almost every day for nine weeks, and frequently in large numbers. 

 Of course I began to suspect that the males must moult into a 

 brown suit after nesting, as do our Bobolinks and many other 

 birds, but I shot specimens at various times, and all proved to be 

 either females or young males, and as I was confident that at 

 Concepcion black males were to be found through the year, I 

 was at a loss for an explanation, and am so still. 



^S. Machetornis rixosa {Vieill.). — ^Occurs sparingly 

 through the winter at Concepcion, and a few may remain to 

 breed. Not elsewhere noted. On July 30, 18S0, I found a 

 small flock among trees on a slope close to the edge of a meadow. 

 They were quite unsuspicious and I watched them some time 

 before shooting any. In moving from place to place they kept 

 together and first alighted on trees, afterward going down to the 

 ground where they ran about as easily and gracefully as Thrushes. 

 Their general appearance, even to points of color, so strongly 

 suggested a true Tyrait?ius (e.g., T. melancholicus) that their 

 easy motion on the ground was rather surprising until you noticed 

 that their legs did not justif}^ such a comparison. During the 

 warmer weather the few which remained seemed to be solitary. 



59. Centrites niger {Bodd.). — One .cold, misty morning, 

 the last of April, a few of these birds made their appearance at 

 Concepcion. They gradually increased in numbers vmtil July, 

 when they were very abundant everywhere in open ground. The 

 adult males were jet black with a patch of chestnut in the middle 

 of the back. The females and young of the year were dull ashy 

 inclining to tawny, and as the time wore on the feathers wore 

 off" and many of the dull colored birds were metamorphosed 

 into good-looking males in spring plumage. I think this is 



