Bulletin - United States National Museum - si-pddr - Smithsonian ...

74 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
with buffy brown, on hind crown, and hind neck; loral region and
stripe extending under eye biiffy brown, with a faintly indicated
whitish spot at base of bill on loral region ;
streak behind eye clove
brown; superciliary streak, lower eyelid, and poorly defined auri-
cular streak whitish ; lower hind neck, upper back, and wings with
down clove brown basally, buffy brown distally, the lighter color
predominating and extending down on sides of breast ; rest of upper
parts deeper than clove brown; streak extending across posterior
side of forearm to base of wing, and from there in a somewhat ir-
regular line on either side of back to line of thighs whitish ;
under-
parts whitish with a slight buffy tinge; and indistinct collar of buffy
brown across upper breast. The specimens taken are very uniform
in color.
The southern pintail was common in the fresh water of marshy
pools and channels near Lavalle in the Province of Buenos Aires at
the end of October, 1920. On November 6, following a severe storm
of wind and rain that flooded large areas and killed many thousand
sheep, a great migration of these birds came in from the south, the
flight continuing during morning and evening for a period of three
days. At the time I was in camp in the sand-dune area on the
east coast of the Province of Buenos Aires, about 24 kilometers south
of Cape San Antonio.
In flocks and pairs pintails came swinging in to feed on areas of
flooded land adjacent to the dunes. The birds showed little fear,
and if I merely crouched on the ground had no hesitancy in passing
within 60 meters, so that I killed four without difficulty. On the
evening of November 7 the flight from the south was greatly in-
creased, the birds passing in flocks of half a dozen to one hundred.
The larger flocks traveled in irregular lines, the birds more or less
abreast, passing steadily to the northward from 30 to 60 meters from
the ground, while occasional bands swung around to drop in on some
suitable feeding ground. At intervals I noted pairs of ducks, male
and female flying together, alone or in company with flocks, but
during the entire movement certainly more than 95 per cent of the
pintails seen were males. The following morning the flight began
again at daybreak and continued until about 10 in the morning.
Flocks scattered out to feed over the pampa covered with shallow
water from the rains. The total number of birds seen on this day
between 5 o'clock in the morning and noon was estimated at between
15,000 and 20,000 individuals. As before, more than 95 per cent of
those observed near at hand were males, and it was assumed that
this proportion held among those noted at a greater distance. Male
birds that I shot were still in full breeding condition. From the
make-up of the flocks it was my belief that in Dafla spinicauda^ as