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. 



