_Nycticorax caledonicus pelewensis_ Mathews, Bull. British Ornith.
Club, 46, 1926, p. 60. (Type locality, Pelew Islands.)
_Nycticorax caledonicus_ Hartlaub and Finsch, Proc. Zool. Soc.
London, 1868, pp. 117, 118 (Pelew); Sharpe, Cat. Birds British
Mus., 26, 1898, p. 158 (Pelew); Hartert, Novit. Zool., 7, 1900, p.
10 (Ruk); Reichenow, Die Vögel, 1, 1913, p. 255 (Palauinseln);
Takatsukasa and Kuroda, Tori, 1, 1915, p. 50 (Pelew); Uchida,
Annot. Zool. Japon., 9, 1918, p. 486 (Palau); Wetmore, in Towsend
and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 172 (Uala, Truk
Atoll); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 37 (Pelew,
Ruk).
_Nycticorax manillensis_ Hartlaub and Finsch, Proc. Zool. Soc.
London, 1872, pp. 89, 105 (Pelew); Finsch, Journ. Mus. Godeffroy,
8, 1875, pp. 5, 33 (Palau); _idem_, Proc. Zool. Soc. London, 1880,
p. 577 (Ruk); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy,
1881, p. 353 (Ruk); Wiglesworth, Abhandl. und Ber. Zool. Mus.
Dresden, no. 6, 1890-1891 (1891), p. 69 (Pelew, Ruk).
_Nycticorax caledonicus pelewensis_ Mathews, Syst. Avium
Australasianarum, 1, 1927, p. 200 (Pelew, Carolines); Peters,
Proc. Boston Soc. Nat. Hist., 39, 1930, p. 271 (Pelew, Carolines);
Peters, Check-list Birds World, 1, 1931, p. 115 (Pelew); Hand-list
Japanese Birds, rev., 1932, p. 183 (Palau, Truk); Hand-list
Japanese Birds, 3d ed., 1942, p. 204 (Babelthuap, Koror, Coracel,
Truk); Amadon, Amer. Mus. Novit., no. 1175, 1942, p. 6 (Palau,
Ruk); Mayr, Birds Southwest Pacific, 1945, p. 285 (Palau, Truk);
Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 43
(Angaur, Peleliu, Garakayo, Truk).
_Geographic range._--Micronesia: Palau Islands--Babelthuap, Koror,
Coracel, Garakayo, Peleliu, Ngabad, Angaur; Caroline Islands--Truk.
_Characters._--Adult: Size medium; head and nape dark slaty-black;
occipital plumes white with dark tips and shafts; back dark
reddish-brown, lighter on sides of neck, wings, wing coverts,
rump, and tail; under parts whitish with light reddish-brown on
sides of neck extending to throat and upper breast; tibia with
some brownish feathers; underwing pinkish; feet yellowish-brown;
bill black.
Immature: Resembles adult, but upper parts mottled black with
reddish-brown; underparts with lighter streaks of brown and
whitish on breast; feet yellowish; bill black above, yellowish
below.
Adult resembles _N. c. manillensis_ Vigors, but is duller above.
_Measurements._--Two adult males from Peleliu measure: wing, 293,
299; tail, 105, 107; culmen, 82, 89; tarsus, 79, 81; seven adult
females from Peleliu: wing, 269-286 (280); tail, 101-106 (104);
culmen, 76-84 (80); tarsus, 78-83 (80); one adult female from
Truk: wing, 280; tail, 97; culmen, 83; tarsus, 79.
_Specimens examined._--Total number, 27 (5 males, 18 females, 4
unsexed), as follows: Palau Islands, USNM--Peleliu, 9 (Aug. 31,
Sept. 1, 5, 6, 8, Dec. 6); AMNH--exact locality not given, 16 (Nov.
7, 8, 13, 23, 25, Dec. 1, undated); Caroline Islands, USNM--Truk, 1
(Feb. 16); AMNH--Truk, 1 (May 25).
_Nesting._--The NAMRU2 party observed a nesting colony of these
night herons at Peleliu on August 29, 1945. Approximately eight
nests were observed in a grove of saplinglike trees at the edge of
a mangrove swamp. These nests were 15 to 20 feet above the ground;
most of them contained one or two nestling birds. Two subadults and
three nestlings in postnatal molt were obtained; no eggs were
found. Marshall (1948:219) records breeding in August, September
and December.
_Food habits._--Baker (1948:43) reports that stomachs of night
herons obtained by the NAMRU2 party at Peleliu contained a great
variety of animal foods, including eels, fish, lizards (skinks),
crabs, shrimp, and insects. The stomach of one adult contained 14
large grasshoppers and four fish, totaling about 15 cc. in volume.
The nestlings had eels, skinks, and insects in their stomachs.
_Parasites._--Uchida (1918:486) found the bird louse (Mallophaga),
_Lipeurus baculus_, on the night heron at Palau.
_Remarks._--Amadon (1942:4-8) has made the most recent study of the
species _Nycticorax caledonicus_ and recognizes eight subspecies from
Australia and New Calendonia north to the Caroline and Bonin islands.
This is one of the few tropical and subtropical species which has
extended its range to the Bonin islands. The discontinuous distributions
of this species prevents an accurate estimation of the route by which it
reached the Bonins. The presence of the bird at Palau and at Truk makes
it difficult to account for its absence at Yap and other intervening,
and seemingly suitable, islands. Populations at Palau and Truk appear to
be similar and are placed in the same subspecies, but when adequate
material is available from Truk, further study may reveal that the
populations on the two islands (Truk and Palau) are recognizably
different.
At the southern Palau Islands, night herons were found by the NAMRU2
party in mangrove swamps, lagoons and on beaches. I found them to be
inactive during the daytime; the birds were usually perched singly in
trees or at the edge of the water. The birds appeared to have special
roosting places and were observed sitting in the same place on several
different occasions. McElroy of the NAMRU2 party reported seeing three
night herons at Truk in December, 1945.
=Gorsachius goisagi= (Temminck)