Notes on the Marianas Mallard 1 
Yoshimaro Yamashina 
The Marianas Mallard, Anas oustaleti, is 
one of the most interesting species of Micro- 
nesian birds. Found only on Saipan, Tinian, 
and Guam, three small islands of the Marianas, 
it is very scarce both in museum collections and 
in its native habitat. Special precautions, there¬ 
fore, should be taken to protect it from ex¬ 
termination. 
The Marianas Mallard was first reported by 
Bonaparte (1856) as Anas boschas a. Freycineti 
( nom. nud.) based on the single specimen pre¬ 
served in the Paris Museum, which was said to 
have come from "Les Isles Malouines.” Later 
Salvadori (1894) described the same specimen 
as Anas oustaleti, but its exact abode was not 
known until Oustalet (1896) reported six spe¬ 
cimens from Guam. Afterwards, Hartert (1898) 
added Saipan to its range, and Phillips (1923) 
added Tinian. Its habits and status, however, 
were unknown until Japanese investigators 
studied them after 1931. 
Anas oustaleti is found in two places in 
Saipan. One is a lagoon covered with man¬ 
groves, north of Garapan village, where Hyo- 
jiro Orii, my collector, obtained 11 specimens 
in 1931 and Takeo Kozima later took four more 
for me. The second place is a small fresh-water 
pond called Charan-Kanoa, south of Garapan 
village, surrounded by a rich growth of aquatic 
plants. 
Tinian Island, south of Saipan, is at present 
the main habitat of this duck. Hagoi Pond, in 
the northern part of that island, is a small body 
of fresh water surrounded by about 40 acres 
1 Submitted with the approval of the Chief, Natural 
Resources Section, General Headquarters, Supreme 
Commander for the Allied Powers, Tokyo, Japan. 
Manuscript received November 4, 1947. 
of marsh. My collectors obtained nine speci¬ 
mens there between 1931 and 1933. Kuroda 
obtained 10 more specimens from this locality 
in 1936, and in 1940 he received four live birds 
which he kept in his aviary in Tokyo for several 
years. According to Kuroda, his collector ob¬ 
served two flocks of Anas oustaleti there at the 
time, each containing 50 to 60 ducks, the largest 
flocks of this duck ever seen. 
In Guam, where Anas oustaleti was first dis¬ 
covered, the Marianas Mallard seems to be least 
plentiful in comparison with the other two 
islands. According to Phillips (1923) only a 
few ducks remain in the Talafofo Valley. 
In general habits Anas oustaleti resembles 
Anas poecilorhyncha (including superciliosa ), 
which is widely distributed from New Zealand 
through Micronesia and the Philippines to 
China and Japan. The duck resides in lagoons 
and fresh-water ponds throughout the year, and 
according to Phillips (1923) breeds in Guam 
in January and February, at the end of the rainy 
season. On Saipan and Tinian eggs and duck¬ 
lings have been collected in June and July, 
which are in the dry season (Kuroda, 1942). 
Saipan natives speak of their breeding from 
January to March. Thus, this duck seems to 
breed at all seasons of the year. Kuroda (1942) 
described a nest with seven eggs taken July 4, 
1941, at Hagoi Pond, Tinian Island. It was 
found among the rushes, and was made of dead 
leaves, stems, and roots, and lined with down. 
The eggs were grayish white with a pale green¬ 
ish tinge, and measured 61.6 X 38.9 mm. 
Anas oustaleti has two types of plumage, one 
resembling Anas platyrhynchos, and the other 
Anas poecilorhyncha. Therefore, certain earlier 
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