120 Mr. J. Graham Kerr on the Avifauna 



X, — On the Avifauna of the Lower Pilcomayo. By J. 

 Graham Kerr, Naturalist to the Pilcomayo Expedition. 

 With Notes by the Editor. 



(Plate III.) 

 I. Introduction. 

 The Rio Pilcomayo, as is well known, is one of the chief 

 affluents of the Rio Paraguay from the western side. Rising 

 in the Andes of Bolivia, its course to the south-eastward 

 lies through the heart of "El Gran Chaeo,^' an extensive 

 region which has resisted with unusual success most of the 

 numerous attempts at its exploration. As well from its geo- 

 graphical position as from the high-flown fictions which have 

 been written of it by various South- American authors, great 

 hopes were entertained of its turning out a very paradise 

 to the zoologist and botanist. In the beginning of 1889 an 

 opportunity presented itself for the investigation of its 

 biological features : a large expedition was fitting out for 

 the exploration of the Pilcomayo, and the leader of this, 

 Capt. Juan Page of the Argentine Navy, was good enough 

 to intimate to Mr. Sclater his willingness to allow a naturalist 

 to accompany him. Hence it was that I became naturalist 

 to this expedition. The readers of ' The Ibis ' have been kept 

 well informed of the progress of the expedition from time to 

 time, and it will not therefore be necessary to say more than 

 a few words regarding it here. 



Upon January 1st, 1890, the expedition left Buenos Ayres 

 on board the specially-l)uilt steamer ' Bolivia.' After a 

 tedious journey up the Paranji, and a further stoppage at 

 Puerto Juarez Celman, opposite the city of Corrientes, the 

 mouth of the Pilcomayo was reached early on March 12tli, 

 and the same afternoon the 'Bolivia' entered the river. 

 Eleven days of comparatively uninterrupted navigation along 

 its narrow and extremely tortuous waters brought the expe- 

 dition to " Las Juntas,'' the point at which the two branches, 

 of which the Pilcomayo is said to consist for a great part of 

 its course, unite. The 'Bolivia' now entered the northern 

 branch of the river, and immediately its progress became very 



