_Atagen (sic) Ariel_ Gray, Gen. Birds, 3, 1845, col. pl. [185].
(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