Part 122

Zosterops finschii Gray, Hand-list Birds, 1, 1869, p. 164 (Pelew); Gadow, Cat. Birds British Mus., 9, 1884, p. 197 (Pelew); Bolau, Mitteil. Naturhist. Mus. Hamburg, 1898, p. 60 (Palau).

Zosterops finschi Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 89, 96 (Pelew); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 4, 17 (Palau); idem, Journ. Mus. Godeffroy, 12, 1876, p. 27 (Palau); Giebel, Thes. Ornith., 3, 1877, p. 775 (Pelew); Finsch, Journ. f. Ornith., 1880, p. 300 (Pelew?); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 407 (Palau); Tristram, Cat. Birds, 1889, p. 211 (Pelew); Wiglesworth, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 36 (Pelew); Finsch, Das Tierreich, no. 15, 1901, p. 45 (Palau); Dubois, Syn. Avium, 1, 1902, p. 713 (Pelew); Reichenow, Die Vögel, 2, 1914, p. 470 (Palau); Takatsukasa and Kuroda, Tori, 1, 1915, pp. 55, 64 (Pelew); Stresemann, Mitt. Zool. Mus. Berlin, 17, 1931, p. 230 (Palau); Hand-list Japanese Birds, rev., 1932, p. 173 (Palau); Hand-list Japanese Birds, 3d ed., 1942, p. 192 (Babelthuap, Koror).

Tephras finschi Matschie, Journ. f. Ornith., 1901, pp. 112, 113 (Palau); Kuroda, in Momiyama, Birds Micronesia, 1922, p. 77 (Pelew); Mathews, Syst. Avium Australasianarum, 2, 1930, p. 712 (Pelew).

Zosterops cinerea finschi Mayr, Birds Southwest Pacific, 1945, p. 300 (Palau).

Zosterops cinerea finschii Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 74 (Peleliu, Garakayo).

Geographic range.--Micronesia: Palau Islands--Babelthuap, Koror, Garakayo, Peleliu, Ngabad.

Characters.--Adult: Resembles adult of Z. c. cinerea, but upper parts mostly browner; wing and tail feathers browner; head blacker; rump lighter than back; auriculars grayish-brown; lores dark; sides of head and neck brownish; underparts mostly dark; chin and throat smoky gray; breast and abdomen more brown less gray; sides, flanks and under tail-coverts brown. Resembles adult of Z. c. ponapensis, but larger with underparts more buffy; upper parts darker.

Measurements.--Measurements are listed in table 51.

Specimens examined.--Total number, 37 (15 males, 19 females, 3 unsexed), as follows: Palau Islands, USNM--Babelthuap, 1 (Nov. 27)--Koror, 3 (Nov. 4, 5)--Garakayo, 6 (Sept. 18)--Peleliu, 5 (Aug. 27, Sept. 10); AMNH--exact locality not given, 22 (Oct., Nov., Dec.).

Molt.--Many of the specimens of Z. c. finschii taken in the period from August to December show evidences of molt. Some of the birds taken in November and in December appear to be in fresh plumage. All three subspecies of Z. cinerea evidently undergo a period of molt in the late summer and fall.

Remarks.--The Micronesian Dusky White-eye of Palau was found on several of the islands of the southern Palaus by the NAMRU2 party in 1945. The bird was observed in flocks of five or more individuals moving rapidly through the foliage of trees and shrubs. It was not found in the dense, undisturbed jungle areas, but rather in second growth vegetation and along the margins of woodlands. At Peleliu, birds were noted in trees and shrubs along the roadways; at Garakayo, birds were seen in low trees near the summits of hills. At Garakayo, Z. cinerea and Z. conspicillata were found in the same areas near the tops of the hills. Both species appeared to be feeding on seeds of the same trees (unidentified but resembling the hibiscus). Z. cinerea was more numerous than Z. conspicillata and appeared (from observations made on September 18, 1945) to be the dominant species and was seen to chase the smaller Z. conspicillata away. Coultas (field notes) found Z. cinerea "fairly common" in 1931 at Palau.

Evolutionary history of Zosterops cinerea.--The dusky white-eyes of Micronesia were considered as separate species until 1944, when Mayr (1944b:7) treated them as conspecific, stating that the bird at Ponapé has characters intermediate between those at Kusaie and Palau. Earlier, Hartert (1900:3) suggested a close association between Z. cinerea and the species at Truk (now Rukia ruki). Mayr concludes that Z. cinerea and R. ruki are not closely related, and points out that the absence of a white orbital ring in Z. cinerea does not necessarily mean that the bird should be considered as belonging to a genus other than Zosterops.

The pathway of colonization and the ancestral stock of Z. cinerea are not certainly known. Among the white-eyes of the Polynesian, Melanesian and Malayan areas, there are few kinds which Z. cinerea resembles closely. Mayr (1941b:204) writes that the Z. cinerea at Ponapé was derived from either Polynesia or Papua. I find little in common between Z. cinerea and the species in these areas, and in my opinion Z. cinerea is closest to Z. atriceps of the Moluccas. Z. atriceps has plumage which is part grayish and part brownish. Its underparts resemble those of Z. c. cinerea but are paler gray; crown, neck, and shoulder much like that of Z. c. ponapensis and Z. c. finschii; and bill resembling that of Z. c. cinerea. Z. atriceps differs by having olive-green coloring on back and wings and yellowish coloring on under side of tail. Thus, it is possible that Z. cinerea invaded Micronesia from the Moluccan region, reaching either Palau or Ponapé initially.

=Rukia palauensis= (Reichenow)

Palau Greater White-eye

Cleptornis palauensis Reichenow, Journ. f. Ornith., 1915, p. 125. (Type locality, Babeldzuap = Babelthuap, Palauinseln.)

Megazosterops palauensis Stresemann, Ornith. Monatsber., 38, 1930, p. 159 (Baobeltaob); Snouckaert, Alauda (2), 3, 1931, p. 26 (Palau); Stresemann, Mitt. Zool. Mus. Berlin, 17, 1931, p. 235 (Baobel Taob = Babelthuap); Mathews, Ibis, 1931, p. 48 (Palau); Hand-list Japanese Birds, rev., 1932, p. 172 (Palau); Yamashina, Tori, 10, 1940, p. 674 (Palau); Hand-list Japanese Birds, 3d ed., 1942, p. 191 (Babelthuap, Peleliu).

Rukia palauensis Mayr, Amer. Novit., no. 1269, 1944, p. 7 (Palau); idem, Birds Southwest Pacific, 1945, pp. 294, 300 (Peliliu); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, pp. 67, 74 (Peleliu).

Geographic range.--Micronesia: Palau Islands-Babelthuap, Peleliu.

Characters.--Adult: A large white-eye with upper parts near "Saccardo's olive" (some individuals darker brown), head and neck more olivacious, rump browner; auriculars blackish with pale yellow streaks; narrow supra-orbital stripe pale olive; orbital ring indistinct; underparts near "olive lake," chin lighter, under tail-coverts light yellowish-brown; wing and tail feathers dark brown, except for tawny outer edges and whitish inner edges; maxilla horn-color; mandible yellowish to tawny; feet tawny; iris grayish-brown.

Measurements.--Measurements of Rukia are listed in table 52. Measurements of males and females are comparable within the same species.

TABLE 52. MEASUREMENTS OF Rukia

=================+======+=========+=========+=============+========= SPECIES | No. | Wing | Tail | Culmen | Tarsus -----------------+------+---------+---------+-------------+--------- R. palauensis | 19 | 80 | 54 | 21.5 | 25 | | (76-84) | (51-57) | (20.0-22.5) | (24-26) | | | | | R. ruki | 8 | 81 | 52 | 21.5 | 23 | | (76-85) | (51-52) | (20.0-23.0) | (22-24) | | | | | R. sanfordi | 18 | 70 | 44 | 23.0 | 21 | | (67-71) | (41-47) | (22.0-24.0) | (20-22) -----------------+------+---------+---------+-------------+---------

Specimens examined.--Total number, 21 (12 males, 9 females), as follows: Palau Islands, USNM--Peleliu, 11 (Aug. 27, 29, 30, Sept. 4, 5, 6, 7, Dec. 4, 5); AMNH--Peleliu?, 10 (Dec.).

Molt.--Specimens taken in August and September are in worn plumage, a few individuals show evidence of molt. Specimens taken in December are in fresh plumage, although two or three individuals are in the final stages of molt. This places the period of molt as September, October, and November. Nesting evidently occurs in the summer; one male taken on August 27, 1945, had enlarged gonads.

Remarks.--The Palau Greater White-eye was described under the generic name Cleptornis by Reichenow. This generic allocation was not followed by subsequent authors; Stresemann proposed the generic name Megazosterops in 1930, and Mayr (1944b:7) placed this white-eye in the genus Rukia along with other large white-eyes from Micronesia. In employing this name, Mayr writes, "The generic names Rukia (for ruki) and Kubaryum (for oleaginea) were published simultaneously in the same publication. As first reviser I select the name Rukia, which not only is shorter but is also based on a species which I have been able to examine."

R. palauensis is recorded from Babelthuap and Peleliu of the Palau Islands. In 1931, Coultas found the birds only at the island of Peleliu, where he obtained nine specimens from a flock. In 1940, Yamashina (1940:674) writes that it is a very rare species at Palau. Marshall (1949:219) found the bird at Peleliu but at no other islands visited. In 1945, the NAMRU2 party obtained eight specimens at Peleliu from two localities on the eastern side of the island in jungle areas relatively undisturbed by war activities. The birds were fairly common in the brush and vines of the jungle undergrowth at these two areas. There were no flocks seen; usually singles or pairs were noted. The bird bears a striking resemblance to Psamathia annae, which lives in the same environment and has a somewhat similar coloration, shape and posture. These two birds probably have undergone a parallel development. Competition between the two was not noted. Psamathia is evidently less restricted in its distribution.

R. palauensis has a restricted distribution in the Palau Islands, as indicated by the observations of Coultas, the Japanese and the NAMRU2 party. The disturbance resulting from the war activities has undoubtedly influenced the population and restricted further the preferred habitat of this white-eye, especially at Peleliu.