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46 BULLETIN 133, UNITED STATES NATIONAL MUSEUM
willow thickets near the Rio Negro. Here the birds floated about
with back and rump feathers expanded to receive the warm rays of
the sun, or swam with slender necks erect in ordinary grebe attitude.
At times one rose, and with body erect and neck extended forward,
fluttered along the surface for a few feet, an action probably reminis-
cent of mating displays given in spring. At such occasions the white
secondaries showed prominently. At times the grebes gave a
whistled call, often in an explosive tone, that at first I supposed was
the song of some passerine unknown to me. One female taken was
in molt and had cast all of the feathers in the primary and secondary
series in the wing; new feathers growing in had just burst the
sheaths. The birds were observed preening their plumage and eat-
ing discarded feathers. An individual that floated near shore was so
fearless that I turned it about with my hand while attempting to get
it in proper position for a photograph.
At Carhue, in the Province of Buenos Aires, on December 16 a
single bird of this species was observed among great flocks of C.
occipitalis on the alkaline waters of Lago Epiquen. Near Guamini
the species was noted in small numbers in open water of a large lake
on March 3, 4, and 6, 1921.
In the small series at hand are specimens of this grebe secured
in localities ranging from the Straits of Magellan to Bolivia and
central Chile. I am, hoAvever, unable to differentiate those from
the various areas as subspecies. The grebe described from the Falk-
land Islands as rollandi by Quoy and Gaimard is a large repre-
sentative of the present species, distinguished by much larger size
and darker coloration. It is sufficiently distinct to be recognized
as a separate species on the basis of material available at present,
though formerly the name rollandi was used for all grebes of this
type in South America.
COLYMBUS OCCIPITALIS OCCIPITALIS (Garnot)
Podiceps occipitalis Gabnot, Ann. Sci. Nat., vol. 7, January, 1826, p. 50.
(Falkland Islands.)
The name in common use for this bird, taken from Podiceps cali-
pareus^^ is antedated by Podiceps occipitalis Garnot, as cited above.
It may be noted that the description by Lesson and Garnot just cited
is also antedated by plate 45 of the same work, published with liv-
raison 5 in October, 1827, where the bird is figured under the cap-
tion Podiceps kalipareus.^^ Chapman^- has confirmed the validity
of C. o. juninensis (Berlepsch and Stolzmann)^^ described from
30 Lesson and Garnot, Voyage autour du Monde, Coquille, Zoologle, vol. 1, May, 1830,
p. 727.
*» See Matthews, Austral Avian Record, vol. 2, October 23, 1913, p. 53.
"U. S. Nat. Mus., Bull. 117, 1921, p. 49.
^ Ibis, 1894. p. 112.