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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 131
tarsus itself was black. One specimen taken had lost the distal por-
tion of one foot in some ancient injury.
From November 4 to 7 long-tailed jaegers, acompanied by a few
parasitic jaegers, were in migration southward along the broad sand
beach extending southward from Cape San Antonio. On the afternoon
of November 4 three came drifting slowly down to leave two
of their number lying on the sand, while the third, more wary, kept
out of range and continued southward.
During the two days following a tremendous gale of wind and
rain made field work useless, so that I was confined to short excursions
about camp. Occasional jaegers passed, keeping low down
behind the shelter of the dunes, sweeping by at high speed, driven
by the high velocity of a quartering wind. With fairer weather on
November 7 the birds increased and were in sight constantly, all in
silent passage toward some winter range in the south. The number
that I actually saw during the period of my observations must have
ranged between 1,200 and 1,500, while the total number of indi-
viduals that passed was far in excess of this.
The birds traveled alone or in little groups of three or four, some
wary and others very tame. They drifted along, frequently scaling
for long distances or occasionally flapping their wings, never more
than 50 feet in the air, often only a few feet above the sand. At
intervals one dropped lightly to the beach near the water mark to
pick up a few beetles that had drifted ashore after the storm and
then remained to rest for a few minutes. Others more energetic
harried the Trudeau's terns with agile wing strokes until they disgorged
their prey of fish on the sand, when the jaeger stooped easily
to pick it up and then continued its flight. Their steady southward
movement without pause to circle about or return was most
impressive.
Family LARIDAE
LARUS DOMINICANUS Lichtenstein
Larus dominicanus Lichtenstein, Verz. Doubl. Zool. Mus. Berlin, 1823,
p. 82. (Coast of Brazil.)
In a recent paper Fleming" has named a form of this gull from
the South Shetland Islands on basis of lighter color. Mathews and
Iredale ^^ list the black-backed gull of New Zealand as Larus domint
amus antipodus (Bruch) without comment as to the differences con-
sidered as a basis for' this subspecific designation. After study of
an insufficient series of dominicanus that includes specimens from
both Atlantic and Pacific coasts of South America, New Zealand,
15 Larus dominicanus austrinus Fleming, Proc. Biol. Soc. Washington, vol. 37, Dec.
29, 1924, p. 139. (Deception Island, South Shetland Islands.)
" Ibis, 1913, p. 248.