_Anas superciliosa_ var. _pelewensis_ Hartlaub and Finsch, Proc.
Zool. Soc. London, 1872, p. 108. (Type locality, Pelew Islands.)
_Anas superciliosa_ Hartlaub and Finsch, Proc. Zool. London, 1868,
pp. 8, 118 (Pelew); Sclater, Proc. Zool. Soc. London, 1869, p. 659
(Pelew); Gray, Hand-list Birds, 3, 1871, p. 82 (Pelew); Salvadori,
Ornith. Papuasia, 3, 1882, p. 395 (Pelew); Wiglesworth, Abhandl.
und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 70
(Pelew); Salvadori, Cat. Birds British Mus., 27, 1895, p. 206
(Pelew); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8,
1896, p. 50 (Palaos).
_Anas superciliosa pelewensis_ Dubois, Syn. Avium, 2, 1904, p. 990
(Pelew); Mathews, Birds Australia, 4, 1915, p. 90 (Pelew);
Phillips, Nat. Hist. Ducks, 2, 1923, p. 113 (Pelew); Mathews,
Syst. Avium Australasianarum, 1, 1927, p. 215 (Pelew); Hartert,
Novit. Zool., 36, 1930, p. 112 (Pelew); Peters, Check-list Birds
World, 1, 1931, p. 160 (Pelew); Hand-list Japanese Birds, rev.,
1932, p. 184 (Palaus, Truk); Hand-list Japanese Birds, 3d ed.,
1942, p. 205 (Babelthuap, Peliliu); Amadon, Amer. Mus. Novit., no.
1237, 1943, p. 3 (Palau); Mayr, Birds Southwest Pacific, 1945, p.
286 (Palaus, Truk); Baker, Smithson. Misc. Coll., vol. 107, no.
15, 1948, p. 45 (Peleliu, Truk).
_Anas pelewensis_ Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 5,
40 (Palau); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy,
1881, p. 407 (Palau); Bolau, Mitteil. Naturhist. Mus. Hamburg,
1898, p. 71 (Palau).
_Polionetta superciliosa pelewensis_ Kuroda, in Momiyama, Birds
Micronesia, 1922, p. 38 (Pelew).
_Anas superciliosa rukensis_ Kuroda, "Gan to Kamo" (Geese and
Ducks), 1939, page not numbered, description between pls. 52 and
53 (Type locality, Ruk); Hand-list Japanese Birds, 3d ed., 1942,
p. 206 (Truk).
_Anas poecilorhyncha superciliosa_ Delacour and Mayr, Wilson
Bull., 57, 1945, pp. 21, 39 (no locality given); Yamashina,
Pacific Science, 2, 1948, p. 122 (Palau, Truk).
_Geographic range._--Islands of Micronesia, Polynesia, and
Melanesia. In Micronesia: Palau Islands--Babelthuap, Peleliu;
Caroline Islands--Truk.
_Characters._--Adult: A medium-sized duck with upper parts dark
brown, feathers edged with buff; top of head blackish merging into
gray on hind neck with narrow buff line below; eye-stripe broad
and blackish; lower parts uniformly dark brown to gray brown,
feathers edged with buff; face, chin and throat light buff with
some dark streakings; under wing white; speculum green; bill
plumbeous with nail black; legs yellow-brown to yellowish, webs
dusky. _A. p. pelewensis_ resembles _A. p. rogersi_ Mathews, but is
smaller with a wing length averaging as much as 20 mm. shorter.
_Measurements._--As given by Amadon (1943:4) seven unsexed skins
from the Palaus, studied by Finsch (1875:40), have wing lengths of
207, 212, 212, 214, 223, 235, 230. For an adult male taken by
Coultas at Palau, the exposed culmen measures 45 and the tarsus 37.
_Specimens examined._--Total number, 3 males from Palau Islands,
AMNH--exact locality not given (Oct. 26, Nov. 25).
_Remarks._--_A. p. pelewensis_ is apparently rare in the Palau Islands.
Coultas, who visited the Palaus in October to December, 1931, writes
(field notes) that he received reports that the birds were present and
nested in numbers on fresh water lakes. He took specimens in taro
patches and comments that the ducks probably feed at night and have
retiring habits during the day. At Peleliu in 1945, the NAMRU2 party
received several reports of ducks but failed to find the birds. At Truk,
in December, 1945, McElroy of the NAMRU2 party found ducks to be fairly
numerous in rice paddies, marshes, and swamps. He observed that the
birds roosted at Moen Island at night but that they apparently flew to
outlying islands to spend the day. Richards observed ducks on Moen
Island on August 28 and 29, 1947, and again in the period from January
19 to February 10, 1948. He saw several flocks of ducks including one
containing "about a dozen ducks" at ponds along a roadway and at an
airstrip. Kuroda named the population at Truk as distinct in 1939. I
have not been able to examine his description and no specimens are
available for study, but if the birds at Truk represent an independent
colonization (different from that of the birds at Palau) they might
exhibit recognizable variation. Amadon (1943:5) has already pointed out
that the shortness of the wing of specimens in the Palaus may merit
subspecific status for the population. Delacour and Mayr (1945:21)
propose that the Palau Gray Duck is a subspecies of _A. poecilorhyncha_;
this treatment is followed in the present work.
_Evolutionary history._--_A. p. pelewensis_, as Amadon (1943:1) has
stated, represents a population of mallards which became separated from
the ancestral stock in the Australian or Malayan area and when once
differentiated, invaded New Zealand and other parts of Polynesia,
Melanesia, and southwestern Micronesia. Amadon points out that its range
in the Pacific islands is more or less complimentary to that of _A.
oustaleti_ in the Marianas and the Philippine Mallard (_A.
poecilorhyncha luzonica_ Fraser), as well as to the Hawaiian forms (_A.
wyvilliana_ Sclater and _A. laysanensis_ Rothschild). The range of _A.
p. pelewensis_ gives one the impression that its present distribution
may be only a stage in a gradual spreading of the species, for it
certainly has not yet occupied all habitats suitable for it in southern
Micronesia nor elsewhere in Oceania. As in the case of _A. oustaleti_,
_A. p. pelewensis_ appears to prefer areas of fresh, and possibly
brackish, water on the larger islands.
_A. p. luzonica_ is a near relative of _A. p. pelewensis_ but has
rufous-brown instead of buffy-brown coloring on the chin, throat, sides
of head, and superciliary region. The underparts of the Philippine
Mallard are much less mottled. The specula are similar. Both of these
forms were probably derived from a mallard of the _A. p. poecilorhyncha_
type.
=Anas querquedula= Linnaeus