8 4 
Barrows on Birds of the Lower Uruguay . 
[April 
unless an unusually dry season makes their abode convenient 
grazing ground for herds of cattle, or an unusually wet one brings 
all flesh into competition along the edge of hard ground, often 
several miles back from the river margin. 
The river itself varies in width from half a mile in a few places 
to five times that distance in others, while in time of flood 
(“creciente”) it oversteps all bounds and claims the whole valley 
from bluff to bluff. 
Owing to the mildness of the winter comparatively few birds 
seemed to be really migratory at this place, and from the irregu- 
larity of the observations made during the spring, and the fact 
that only one entire spring was spent at Concepcion, the dates of 
arrival in most cases can be only approximately inferred. 
The few brief visits which were made to large tracts of heavy 
woods showed that undoubtedly many other species than those 
actually obtained might have been found there at different seasons 
or under more favorable circumstances. This is certainly true 
with regard to birds of prey, several species of which were not 
met with at all outside of these tracts, though abundant there, 
while still others were not taken at all, though known to abound 
in other parts of the province. Another season in the same local- 
ity would doubtless yield many other species, yet probably not 
many which are regularly to be found in any considerable num- 
bers were overlooked. 
Late in January, 1881, the writer became one of a party dele- 
gated by the Argentine Government to make a provisional exam- 
ination of the fauna and flora of the Pampean Sierras in the 
extreme southern parts of the province of Buenos Aires, — a 
region but imperfectly known, and at that time only recently 
vacated by hostile Indians. Although about ten weeks were 
spent in this work less than half was of any real value, owing to 
the lateness of the season, the imperfect organization of the party, 
etc. The party went by rail on January 25 from Buenos Aires 
to Azul — over 200 miles south-west; thence forward 250 miles 
by diligence to Bahia Blanca on the coast in latitude 38 J degrees 
south, this being the southernmost point reached. From this 
place the course was north 50 miles by saddle and wagon to the 
Sierra de la Ventana (Windowed Sierra) and then westward 75 
or 100 miles along the base of these mountains and the Sierra de 
Currumalan to the military posts of Puan and Carhue, at which 
