_Halcyon owstoni_ Rothschild, Bull. British Ornith. Club, 15, 1904,
p. 6. (Type locality, Asuncion.)
_Halcyon albicillus Sharpe_ (part), Cat. Birds British Mus., 17,
1892, p. 249 (Marianne = Pagan, Agrigan).
_Halcyon albicilla_ Oustalet (part), Nouv. Arch. Mus. Hist. Nat.
Paris, (3), 7, 1895, pp. 169, 170 (Pagan, Agrigan); Hartert,
Novit. Zool., 5, 1898, p. 52 (Pagan, Agrigan).
_Sauropatis chloris owstoni_ Kuroda, in Momiyama, Birds
Micronesia, 1922, p. 59 (Asuncion).
_Leucalcyon albicilla owstoni_ Mathews, Syst. Avium
Australasianarum, 1, 1927, p. 376 (Asuncion).
_Halcyon chloris owstoni_ Takatsukasa and Yamashina, Dobutsu.
Zasshi, 43, 1931, p. 484 (Asuncion); Hand-list Japanese Birds,
rev., 1932, p. 180 (Asuncion); Hand-list Japanese Birds, 3d ed.,
1942, p. 200 (Assongsong, Pagan, Almagan); Mayr, Birds Southwest
Pacific, 1945, p. 293 (Almagan, Pagan, Agrigan, Asuncion); Peters,
Checklist Birds World, 5, 1945, p. 209 (Asuncion, Pagan,
Alamagan); Borror, Auk, 64, 1947, p. 417 (Agrigan).
_Geographic range._--Micronesia: Mariana Islands--Asuncion,
Agrigan, Pagan, Almagan.
_Characters._--Adult: Resembles _H. c. albicilla_, but hind part
of crown blue-green and black collar broader.
Immature: Resembles adult, but forehead buffy and edges of
feathering on anterior crown, upper wing-coverts, and tips of
secondaries brownish.
_Measurements._--Measurements are listed in table 33.
_Specimens examined._--Total number, 4 (2 males, 1 female, 1
unsexed), as follows: Mariana Islands, AMNH--Asuncion, 4 (Jan.,
July).
_Remarks._--Marche obtained specimens of this bird at Pagan in November,
1887, and at Agrigan in December, 1888, and in February, 1889. Owston's
Japanese collectors obtained birds at Asuncion in 1904, which were named
as new by Rothschild. Apparently he used an immature specimen in
preparing the diagnosis of his new subspecies. Borror (1947:417) visited
Agrigan in 1945 and obtained specimens of this kingfisher. He reports
that the bird is a "common and abundant species and probably nests on
the island."
_Evolutionary history of Halcyon chloris in Micronesia._--_Halcyon
chloris_ is distributed from eastern Africa at the Red Sea eastward
through southern Asia to Malaysia, Australia and the Pacific islands.
Peters (1945:207-213) recognized 47 subspecies within this species.
In its colonization of Micronesia, _H. chloris_ apparently arrived first
at the Palaus probably from the Philippines or the Moluccas. Whether
_H. cinnamomina_ was established at Palau prior to the arrival of _H.
chloris_ is unknown. _H. chloris teraokai_ dominates most of the
available habitats at Palau, although it has differentiated but little
from subspecies to the west and southwest of Palau. Among named kinds it
most closely resembles _H. c. chloris_ (Boddaert) of the Moluccas,
Lesser Sundas and adjacent areas in color and structure. The species did
not succeed in establishing itself in the Carolines or at Guam, but did
so in the Marianas at Rota and northward. In comparison with other
subspecies of _H. chloris_ those in the Marianas are characterized by a
slight increase in size and a replacement of the bluish-green coloring
of the head either partly or wholly by white. It is noteworthy that on
the islands of Tinian and Saipan, which occupy a geographically
intermediate position in the Mariana chain, the bird has an almost
completely white head, whereas the birds on islands to the north and
south have only partly white heads.
The geographic ranges of _H. chloris_ and _H. cinnamomina_ in Micronesia
overlap only at Palau as shown by Mayr (1942b:181). Even here each is
restricted to a different habitat. Possibly the present ranges resulted
from competition between each group, and both may have had more
extensive ranges in Micronesia in the past. Another possibility is that
the original stock of _H. chloris_ arrived in Micronesia via the Palaus
and that of _H. cinnamomina_ via Ponapé (eastern Carolinas), and that
the resulting successful colonizations were a matter of chance. If this
were the case the present day ranges may represent the total amount of
dispersal that has taken place. The absence of kingfishers from Kusaie,
Yap, Truk and other apparently suitable islands favors this possibility.
=Eurystomus orientalis connectens= Stresemann