Notes on the Brazilian Merganser in Argentina

Abstract

WHILE on ornithological field trips {n the Province of Misiones (Argentina) between 1949 and 1954, I was able to gather a few notes on the habits of the rare Brazilian Merganser (Mergus octosetaceus). On these trips, sponsored by the Buenos Aires Natural History Museum, our main purpose was to collect specimens and data for a complete analysis of the avifauna of the region; some extra time was devoted to this species, because of its rarity. So little is known about this merganser, that my observations, along with a summary of our present knowledge of the species, may be of some interest to ornithologists. This curious duck, the only South American merganser, was first described by Vieillot in 1817 (Nouv. Dict. Hist. Nat. nouv. ed., 14, p. 222), probably from specimens taken in Brazil by Delalande (Berlioz, 1929: 68-89). Since then it has been reported on only a few occasions. It was found in Brazil by Natterer during his travels between 1817 and 1835 on the Rio Irarare, S5o Paulo, and at GuardaM6r, Minas Gerais (Pelzeln, 1868-70: 322). Friedrich Sellow secured specimens of the Brazilian Merganser during his travels (1818 and 1819) in Rio de Janeiro, Minas Gerais, and S•o Paulo. Although these specimens (now in the Berlin Museum) are simply labelled Minas, they were probably obtained early in 1819 when the travelers followed the Rio das Velhas down to the Rio S5o Francisco (Stresemann, in litt. April 22, 1952; see also Stresemann, 1935: 121; 1948; and 1954: 52). Burmeister (1856: 442) and Schliiter (cf. Berlepsch, 1874: 281) found the Brazilian Merganser in Santa Catarina; two additional specimens from this state are in the Berlin Museum (Stresemann, 1935: 121; 1954: 52). In 1903 another specimen was secured in S5o Paulo (Rio Paranapanema) by Hempell (cf. Pinto, 1938: 58). The last specimen known