Part 24

Fregata minor palmerstoni Hand-list Japanese Birds, rev., 1932, p. 186 (Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie, Namu, Likieb); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam); Yamashina, Tori, 10, 1940, p. 676 (Maug, Bikar).

Fregata minor minor Hand-list Japanese Birds, 3d ed., 1942, p. 207 (Maug, Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie, Namu, Bikar, Likieb).

Fregata minor Borror, Auk, 64, 1947, p. 416 (Agrihan).

Geographic range.--Eastern Indian Ocean to western Pacific Ocean. Limits of range not certainly known. In Micronesia: Mariana Islands--Agrigan, Maug, Saipan, Guam; Caroline Islands--Yap, Faraulep, Truk, Lukunor, Ponapé, Kusaie; Marshall Islands--Namu, Bikar, Likieb, Kwajalein, Bikini.

Characters.--Adult male: Large sea bird with deeply forked tail; blackish but wing-coverts paler; head and back glossy purple and blue; breast lighter than belly. Adult female: Resembles adult male, but head blacker; chin and throat grayer; breast more whitish. Immature: Resembles adult, but head and throat whitish washed with buff; breast dark brown; belly whitish.

Measurements.--Two adult males measure: wing, 572; tail, 354, 396; exposed culmen, 98, 103; two adult females; wing, 583, 604; tail, 365; exposed culmen, 119, 127. These four specimens are from Bikini.

Specimens examined.--Total number, 10 (3 males, 7 females), from Marshall Islands, USNM--Bikini (March 11, 22, 29, 30, April 13, 29, May 3, 14).

Remarks.--The systematic position of the subspecies of Fregata minor in the Pacific area is not well established. I am following the committee who prepared the Hand-list of Japanese Birds (Hachisuka et al., 1942:207) in using the name F. m. minor, although a thorough study may show that these birds have closer relationships to one of the other subspecies of the Pacific area.

Fregata minor has been reported only occasionally in the Marianas and probably is not resident there. Borror (1947:416) reports the bird at Agrihan on August 11, 1945, and Seale (1901:24) mentions one taken at Guam in November, 1889. No records are known from the Palaus. In the Carolines the birds are probably resident, especially in the eastern part. In the Marshalls the species is a conspicuous member of the bird colonies on the coral atolls. Wallace (field notes) observed two birds at Loi Island in Kwajalein Atoll on May 7, 1944. Morrison obtained ten specimens at Bikini in the period from March through May in 1946.

=Fregata ariel ariel= (Gray)

Least Man-o'-War

Atagen (sic) Ariel Gray, Gen. Birds, 3, 1845, col. pl. . (Type locality, Raine Island, Queensland.)

Pelecanus minor Lesson, Traite d'Ornith., 1831, p. 607 (Mariannes, Carolines).

Tachypetes minor Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 831 (Mackenzie Group); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, p. 90 (Uap); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap).

Fregata minor Salvadori, Ornith. Papuasia, 3, 1882, p. 405 (Mariannes, Mackenzie); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 71 (Uap, Ngoli or Matelotas).

Tachypetes aquila var. minor Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 65 (Rota, Carolines, Marshalls); Hartert, Novit. Zool., 5, 1898, p. 68 (Marianne).

Fregata ariel Ogilvie-Grant, Cat. Birds British Mus., 26, 1898, p. 447 (Marianas, Carolines); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 25 (Guam?); Safford, Osprey, 1902, p. 70 (Marianas); Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 15 (Guam).

Fregata ariel ariel Mathews, Birds Australia, 4, 1914-15, p. 285 (Carolines, Marshalls); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 36 (Yap, Ngoli, Rota); Hand-list Japanese Birds, rev., 1932, p. 186 (Rota, Yap, Ngulu, Uluthi); Hand-list Japanese Birds, 3d ed., 1942, p. 208 (Rota, Yap, Ngulu, Uluthi).

Geographic range.--China coast and Philippines south to Australia and east to Pacific islands. In Micronesia: Mariana Islands--Guam?, Rota; Caroline Islands--Yap, Ngulu, Ulithi.

Characters.--Adult male: Resembles F. m. minor, but smaller and blacker with upper parts lustrous greenish-blue and white patch on lower flank.

Adult female: Resembles adult male, but browner with paler nape and white breast. Immature: Resembles adult, but with head, chin, throat, and belly white washed with rufous.

Remarks.--Like F. minor, the Least Man-o'-War has not been observed often in Micronesia. Marche obtained one female at Rota in June, 1888. D. H. Johnson saw a bird thought to be of this species at Agfayan Bay, Guam, on 4 June 1945. Records from the western Carolines are few. There are no reports of this bird from the Palaus and the Marshalls. It may breed on some of the atolls in the Carolines.

The two species of man-o'-war birds may be difficult to distinguish in the field. The smaller size of Fregata ariel is perhaps the most useful character although it may be easily recognized also by the presence of the white flank patch, if it can be observed.

Both of the species of Fregata discussed in this report have representatives in the Atlantic, Indian and Pacific oceans. Murphy (1936:920) has shown that the man-o'-war birds are able to cross the Isthmus of Panamá between the Pacific and Atlantic oceans. This route may also be the means of dispersal for other species. The irregular distribution of these birds as well as of other sea birds in the oceanic islands of the Pacific may be caused by their remaining over waters which contain preferred foods and their avoidance of waters which lack preferred foods.

=Butorides striatus amurensis= Schrenck

Amur Green Heron

Ardea (Butorides) virescens var. amurensis Schrenck, Reise Amur Lande, 1, pt. 2, 1860, p. 441. (Type locality, Amurland.)

Butorides striatus javanicus Hand-list Japanese Birds, rev., 1932, p. 183 (Koror, Babelthuap).