Porphyrio poliocephalus pelewensis Peters, Check-list Birds World, 2, 1934, p. 208 (Pelew); Hand-list Japanese Birds, 3d ed., 1942, p. 222 (Koror).
Porphyrio porphyrio pelewensis Mayr, Birds Southwest Pacific, 1945, p. 288 (Palau); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 49 (Angaur).
Geographic range.—Micronesia: Palau Islands—Koror, Angaur.
Characters.—Adult: A large, purplish-blue, marsh bird with crown and sides of head dusky-black; wing-coverts purplish-blue; rest of upper parts dark, washed with olivaceous-brown; outer webs of primaries and secondaries tinged with purplish-blue; chin, axillaries and under wing-coverts dusky; under tail-coverts whitish; rest of underparts purplish-blue, blacker on abdomen.
Porphyrio p. pelewensis resembles P. p. palliatus Bruggemann of Celebes and P. p. melanopterus Bonaparte of the Moluccas and New Guinea but upper parts paler and slightly less glossy; lesser and primary wing-coverts more purplish-blue and less greenish-blue; outer webs of primaries and secondaries lighter purplish-blue; underparts less blue with patch on throat and breast paler blue with less green (patch present on only one specimen from the Palaus).
Measurements.—Measurements of one male: wing, 227; tail, 81; culmen and shield, 62.5; tarsus, 77; of three females: wing, 212, 218, 227; tail, 77, 81, 86; culmen and shield, 57, 61, 64; tarsus, 75, 75, 77.
Specimens examined.—Total number, 6 (1 male, 3 females, 2 unsexed), as follows: Palau Islands, USNM—Angaur, 1 chick (Sept. 21) AMNH—exact locality not given, 5 (Nov. 13, 19, Dec. 17-19, undated).
Nesting.—A black, downy chick was captured on September 21, 1945, at the edge of a fresh-water lake on Angaur by Davidson of the NAMRU2 party (Baker, 1948:49). Two females taken by Coultas in December had enlarged gonads.
Remarks.—The Purple Swamphen in the Palaus stands out as one of the more distinctive subspecies of P. porphyrio. It also marks the most northeastern extension of the range of this species. The subspecies in the Palaus shows affinities to that found to the south and southwest and probably reached Micronesia via the Papuan area, Celebes or the Moluccas rather than from the Philippines. It is interesting that this bird, as well as several other species, has been able to establish itself at the Palau Islands, but has not extended its range farther into other islands of Micronesia. Perhaps, the bird is now in an early stage in its island occupation.