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

BIRDS OF ARGENTINA, PARAGUAY, URUGUAY, AND CHILE 53
genus Oceanodroma rather than in Procellaria^ where in P. pelagica,
the type species, the tail is slightly rounded.
OCEANITES GRACILIS GRACILIS (Elliot)
Thalassidrotna gracilis Elliot, Ibis, 1859, p. 391. (Chile.)
On the evening of May 7, 1921, 15 kilometers west of Lobos de
Afuera Island, Peru, four graceful petrels, attracted by the lights,
were captured on board ship. On deck they were helpless and even
by aid of their wings were barely able to walk. When handled they
gave a low chirping call. All were males, in which the outermost
primaries had been molted recently, so that one or two of the outer
ones were still inclosed in sheaths. They agree in color and characters
with the type of this species preserved in the National Mu-
seum, save that the wing is shorter, due to the molting primaries.
In most of a series studied by Loomis ^^ the molt came from late
November to early January, though one June specimen had recently
shed the primaries. My skins vary in amount of white on the abdomen
from a diffuse wash on the tips of the feathers in one to another
in which the white forms a solid well-defined patch. The wing in
the type specimen of the species measures 131.2 mm. Measurements
for two of my specimens are 118.3 mm. in each case, but these birds,
as stated above, have just completed a molt and may have the pri-
maries not quite fully grown. They seem, however, to be smaller
than the form described as Oceanites g. galapagoensis Lowe ^^ from
the Galapagos Islands.
Mathews *° has noted that in six specimens of the graceful petrel
five had the tarsus booted, while the other showed indistinct signs of
scutellation. In the six birds that are before me the tarsus is booted
with faint scutes indicated for a short distance at either end.
Order CICONIIFORMES
Family PHALACROCORACIDAE
PHALACROCORAX VIGUA VIGUA (Vieillot)
Rydrocorax vigua Vieillot, Nouv. Diet. Hist. Nat., vol. 8, 1817, p. 90.
(Paraguay.)
The common cormorant, known universally as vigua from its
appellation in Guarani, was observed in many localities. The species
was fairly common on the Rio Paragua}'^, from Corrientes as far
as Asuncion and increased in abundance from that point to Puerto
Pinasco. Scattered individuals were observed at Las Palmas, Chaco,
ssproc. California. Acad. Sci., ser. 4, vol. 2, pt. 2, Apr. 22, 1918, p. 181.
»«Bull. Brit. Orn. Club, vol. 41, June 8, 1921, p. 140.
« Birds of Australia, vol. 2. pt. 1, May 30, 1912, p. 9.