BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 57 



meter 182, Formosa, on August 9 and 14, and an adult pair at 

 Kilometer 80 on September 10. 



These herons were noted in small numbers in the Chaco, where 

 they frequented open marshy lagoons and the borders of esteros. 

 Frequently they walked about on masses of floating vegetation where 

 the water Avas a meter or so deep, or stalked slowly about pools in 

 wet meadows. They were wary and, as they fed in the open, difficult 

 to approach. They fly with a peculiar short stroke of the wing 

 that is highly characteristic, and in flight appear dull gray, with 

 light tail and duller forepart of body, so that when a fallen bird 

 is retrieved the beautiful, blended colors of the plumage come as a 

 sharp surprise. Their alarm note is a harsh quah-h-h quah-h-h, 

 resembling that of other herons, but in addition they give a shrill 

 whistled note that is repeated frequentl3^ The latter call I heard 

 only from birds that were flying, and noted that, as it was given, the 

 neck was outstretched, to be retracted as the whistling was finished. 

 A pair observed in display about a small pool, on September 24, 

 flew swiftly back and forth and then set the wings to sail rapidly 

 in short circles while they turned first one side and then the other 

 to show alternately the dark back and the light breast. The per- 

 formance was executed with a dash and speed that would have done 

 credit to a duck and reminded me in a way of the darting maneuvers 

 executed at times by shore birds. 



In the Chaco the whistling heron was observed as far west as 

 Laguna Wall, 200 kilometers west of Puerto Pinasco, on the Para- 

 guay River. Occasional individuals were seen from January 24 to 

 February 2 at San Vicente, in the Department of Rocha, eastern 

 Uruguay, where I found them at times walking about in dry fields 

 in search of the abundant grasshoppers. Others were noted at 

 Lazcano, February 6, 8, and 9, and one Avas seen at Rio Negro, 

 Uruguay, February 16. 



The species is knoAvn as garza chifflon or simply as chifflon. The 

 Toba Indians called it -pilK' la tse de, while the Anguete knew it by 

 the impressive cognomen of pat gwa zhi gwa Tiiohh. Indians occa- 

 sionally offered the plumes of the wing coverts and nape for barter. 



CASMERODIUS ALBUS EGRETTA (Gmelin) 



Ardea egretta Gmexin, Syst. Nat., vol. 1, pi. 2, 1789, p. 629. (Cayenne.) 



Two adult egrets were seen near Kilometer 80, west of Puerto 

 Pinasco, Paraguay, on September 13, 1920, and four were observed 

 at Carrasco, near Montevideo, Uruguay, on January 16, 1921, a sad 

 commentary on the present status of a bird once found in abundance 

 throughout southern South America. Breeding colonies were re- 

 ported on the Rio Pilcomayo and near the Rio Cebollati in eastern 

 Uruguay. In Argentina herons are protected and traffic in their 



