_Aplornis opaca aenea_ Takatsukasa and Yamashina, Dobutsu. Zasshi,
43, 1931, p. 487. (Type locality, Pagan.)
_Aplonis kittlitzi_ Oustalet (part), Nouv. Arch. Mus. Hist. Nat.
Paris, (3), 7, 1895, p. 212 (Pagan, Agrigan).
_Aplonis opaca harterti_ Momiyama (part), Birds Micronesia, 1922,
p. 11 (Pagan, Agrigan); Kuroda (part), in Momiyama, Birds
Micronesia, 1922, p. 71 (Pagan, Agrigan).
_Aplornis opaca aenea_ Hand-list Japanese Birds, 3d ed., 1942, p.
187 (Asongsong = Asuncion, Agrigan, Pagan, Almagan).
_Aplornis opaca aenea_ Takatsukasa and Yamashina, Dobutsu. Zasshi,
44, 1932, p. 221 (Pagan, Almagan).
_Aplonis opaca aenea_ Hand-list Japanese Birds, rev., 1932, p. 169
(Agrigan, Pagan, Almagan); Yamashina, Tori, 10, 1940, p. 673
(Asongsong).
_Aplonis opacus aeneus_ Mayr, Birds Southwest Pacific, 1945, p.
297 (Agrigan, Pagan, Almagan); Borror, Auk, 64, 1947, p. 417
(Agrihan).
_Geographic range._--Micronesia: Mariana Islands--Alamagan, Pagan,
Agrihan, Asuncion.
_Characters._--Adult: According to Takatsukasa and Yamashina
(1931:487), _A. o. aeneus_ resembles _A. o. orii_ of Palau, but
has a bronze rather than green luster. _A. o. aeneus_ resembles
_A. o. opacus_, but has a smaller bill.
_Remarks._--No specimens of this subspecies have been examined by me.
Little information is available regarding the occurrence of this
subspecies in the northern Marianas. Oustalet (1895:212) writes that
Marche collected four specimens at Pagan and three at Agrihan. Borror
(1947:417) writes that in 1945, it was a "common and abundant species"
at Agrihan. He obtained one specimen between July 27 and August 14 and
comments that it had a grasshopper in its stomach.
_Evolutionary history of Aplonis opacus._--_Aplonis opacus_ is known
from the Mariana, Palau, and Caroline islands in Micronesia. It consists
of several subspecies, which have relatively few distinguishing
characteristics. No starlings are known in the Marshall and Gilbert
islands, although atolls occur in these island-chains that offer a
habitat approximately the same as those in the western Carolines now
occupied by _A. o. angus_.
In regard to parental stock, Sharpe (1876:47) considered _A. opacus_ as
"nothing but a slightly more metallic race of _C. mysolensis_, with a
still stouter bill." The species with which Sharpe compared _A. opacus_
is known from Mysol, Buru, and Ceram. Oustalet (1896:70) thought that
the _Aplonis_ in Micronesia belonged to a group of starlings whose
members are scattered through the Pacific islands including Cook, Samoa,
Tonga, Fiji, New Britain, New Guinea, Banta, Mysol, Salwatti, and Timor.
Mayr (1941b:204) is of the opinion that _Aplonis_ in Micronesia was
derived from central Polynesia. Amadon (1943:8), in his study of the
genera of starlings, places _A. opacus_ within a superspecies containing
_A. cinerascens_, _A. tabuensis_, _A. fuscus_, and possibly _A.
feadensis_ and _A. cantoroides_. All of these are blackish birds with
greenish gloss with immatures having the underparts streaked. In
comparing _A. opacus_ with these mentioned species and with other
species of _Aplonis_, I find that _A. opacus_ more closely resembles _A.
feadensis_ and _A. cantoroides_ than any others. Although there are
differences in size of the bill, wing, and tail, these structures are
proportionally the same. The streaked underparts of the immatures of _A.
cantoroides_ are much like that of the immatures of _A. opacus_, whereas
the immatures of _A. feadensis_ are only faintly streaked with whitish
below. The eye of _A. cantoroides_ is red, and that of _A. opacus_ is
more nearly yellow. The ancestral stock from which _A. opacus_ developed
in Micronesia seemingly reached the area from Melanesia. In Micronesia
the birds dispersed to various groups of islands from some point in the
Caroline Islands. The birds are absent from the Marshall Islands.
Perhaps the birds never reached the Marshall Islands or they may have
been present in former times and disappeared since then.
=Aplonis pelzelni= Finsch