Part 69

The irregular distribution of D. oceanica in the islands of Micronesia and the fact that the bird exists on both "high" volcanic islands as well as on "low" coral atolls suggest that the present population may be a remnant of a once more widely distributed one. The fact that D. oceanica may be divided into several subspecies shows that a greater amount of geographic variation has occurred as compared with its probable ancestral stock, D. pacifica, which is virtually undifferentiated over most of its extensive range. The pigeon of Micronesia has a more rounded wing than that of D. pacifica, which might, as Amadon has suggested, cause the bird to be more sedentary and lend itself more readily to differentiation through geographic isolation. D. pacifica is known to fly from island to island. As shown by the measurements in table 27, the length of wing of D. oceanica differs, in the various insular populations, being longer in the west and shorter in the east. This cline has been discussed by Amadon (1943:11).

It is interesting that Ducula or some other large pigeon has not become established in the Mariana Islands. Ducula is present at Yap and Truk, which are not very distant from Guam. Another tropical pigeon, Columba vitiensis, has extended its range northward and reached the Bonin Islands; probably it arrived there via the Philippines or the Riu Kiu Islands. Thus, there are representatives of large pigeons on islands to the southeast, south, west and northwest of the Marianas, but none has become established in the Marianas themselves.

=Streptopelia bitorquata dusumieri= (Temminck)

Philippine Turtle Dove

Columba dusumieri Temminck, Pl. col., livr. 32, 1832, p. 188. (Type locality, Vicinity of Manila, Luzon, Philippine Islands.)

Colombe Dussumier Quoy and Gaimard, Voy. "Uranie," Zool., 1824, pp. 35, 680 (Mariannes); idem, Ann. Sci. Nat. Paris, 6, 1825, p. 148 (Mariannes).

Columba dusumieri Wagler, Syst. Avium Columba, 1827, p. 266, sp. 99 (Marianis).

Columba Dussumieri Kittlitz, Obser. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, p. 305 (Guahan).

Streptopelia gaimardi Bonaparte, Consp. Avium, 2, 1854, p. 66 (Type locality, Mariannes); idem, Comptes Rendus Acad. Sci. Paris, 40, 1855, p. 18 (Mariannes); Reichenbach, Tauben, 1862, p. 76 (Mariannen).

Turtur (Streptopelia) Giamardi Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 43 (Guam).

Turtur gaimardi Gray, Hand-list Birds, 2, 1870, p. 239 (Marian).

Turtur dussumieri Schlegel, Mus. Pays-Bas, 6, no. 35, 1873, p. 120 (Mariannes); Wiglesworth, Abhandl. Und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 54 (Marianne); Salvadori, Cat. Birds British Mus., 21, 1893, p. 423 (Mariannes); Oustalet, Nouv. Arch. Mus. Hist. Nat. Paris, (3), 7, 1895, p. 222 (Guam); Hartert, Novit. Zool., 5, 1898, p. 60 (Guam, Saipan); Wheeler, Report Island of Guam, 1900, p. 13 (Guam); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 43 (Marianas); Safford, Osprey, 1902, p. 68 (Marianas); idem, Amer. Anthro., 4, 1902, p. 711 (Guam); idem, The Plant World, 7, 1904, p. 264 (Guam); Dubois, Syn. Avium, 2, 1904, p. 760 (Marianne); Safford, Contr. U. S. Nat. Herb., 9, 1905, p. 78 (Guam); Schnee, Zeitschr. f. Naturwisch., 82, 1912, p. 466 (Marianen); Prowazek, Die deutschen Marianen, 1913, p. 101 (Marianen); Reichenow, Die Vögel, 1, 1913, p. 341 (Marianen); Cox, Island of Guam, 1917, p. 20 (Guam).

Streptopelia dussumieri Kuroda, in Momiyama, Birds Micronesia, 1922, p. 54 (Guam, Saipan); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 62 (Marianas); Hand-list Japanese Birds, rev., 1932, p. 189 (Saipan, Tinian, Rota).

Tuttur dessumieri Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 24 (Guam).

Streptopelia bitorquata dusumieri Peters, Check-list Birds World, 3, 1937, p. 96 (Marianne); Hand-list Japanese Birds, 3d ed., 1942, p. 211 (Saipan, Tinian, Rota); Mayr, Birds Southwest Pacific, 1945, p. 289 (Marianas); Watson, The Raven, 17, 1946, p. 41 (Guam); Downs, Trans. Kansas Acad. Sci., 49, 1946, p. 96 (Tinian); Strophlet, Auk, 1946, p. 538 (Guam); Stott, Auk, 1947, p. 526 (Saipan); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 60 (Guam, Rota).

Streptopelia bitorquata Baker, Trans. 11th N. American Wildlife Conf., 1946, p. 208 (Guam); idem, Condor. 49, 1947, p. 125 (Guam).

Geographic range.--Philippine Islands, Sula Archipelago, northern Borneo. In Micronesia: Mariana Islands (introduced)--Guam, Rota, Tinian, Saipan.

Characters.--Adult: A medium-sized dove with head and nape near "light Quaker drab" with a vinous tinge; chin and upper throat whitish becoming near "vinaceous buff" on lower throat and to near "vinaceous-faun" on breast and upper abdomen; lower abdomen, vent, and under tail-coverts white; tibia grayish; neck feathers dark with grayish centers and metallic greenish-slate edges; color near "Japan rose"; back, rump, upper tail-coverts, scapulars, upper wing-coverts, and inner secondaries dark "drab"; sides, upper wing coverts, outer secondaries, and under wing-coverts lead colored; primaries blackish edged with light gray; central tail feathers like back but paler, outer feathers of tail darker with brownish tinge on edges; outermost tail feathers blackish tipped with gray and with outer webs whitish; bill dark; feet reddish; iris orange.

Measurements.--Measurements of 15 adult males from Guam, Rota and Tinian: wing, 154-162 (158); tail, 127-135 (130); culmen, 16.2-18.1 (17.2); tarsus, 24-27 (25.5); of 10 adult females from Guam and Rota: wing, 150-162 (156); tail, 120-130 (127); culmen, 16.2-19.1 (17.5); tarsus, 24-26 (25). No differences in measurements were found between populations from Guam, Rota and Tinian.

Weights.--The author (1948:61) reports the weights of five adult males as 130-167 (152) and of six adult females as 135-159 (146). These birds were taken at Guam.

Specimens examined.--Total number, 27 (16 males, 11 females), as follows: Mariana Islands, USNM--Guam, 21 (Feb. 7, May 25, 26, June 9, July 6, 7, 10, 18, 23, Aug. 2, 11, Sept. 8, Oct. 8)--Rota, 4 (Oct. 18, 22, 23, Nov. 2)--Tinian, 2 (Oct. 24, 25).

Nesting.--The NAMRU2 party found evidences of nesting by this dove at Guam in February, March, April, and June. Nests were observed on May 29 and June 28. On the latter date a nest containing one nestling and one unhatched egg was found near Mount Santa Rosa. The nest was situated approximately five feet from the ground in a low bush. Two eggs taken by Necker at Rota on October 31, 1945, are white and measure 29.6 by 23.0 and 30.1 by 23.0. Strophlet (1946:538) observed a bird carrying nest materials at Guam on November 13. Hartert (1898:60) reports on nests found at Guam in April and May. Each nest contained one egg. It is probable that this bird nests at all times of the year. The nuptial flight of these birds reminds one very much of that of the mourning dove of North America.

Remarks.--The Philippine Turtle Dove was introduced from the Philippines to Guam and other islands of the southern Marianas by the Spanish probably in the 18th Century; it was in 1771-1774 that the Philippine deer (Rusa) was introduced to Guam. Perhaps these birds were initially introduced as caged birds or possibly were liberated to offer hunting for the colonial governors. They have been a very successful introduction and are well established. At Guam (see Baker 1947b:124), this species comprised 15.5 percent of all birds seen along roadways. Although open areas appear to be preferred by this dove and although it may be on the increase owing to the clearing operations of the war effort, it appears to be equally adapted to forested areas and coconut groves. It feeds on the ground to a large extent, fitting into an ecologic niche which few other species of birds of the islands occupy. It was even observed feeding on sandy beaches and tidal flats at low tide.

In 1931, Coultas found the dove to be numerous at Guam, but thought that it was in danger of extinction at Tinian and Saipan owing to extensive hunting. Downs (1946:96) reported that in 1945 the dove was abundant at Tinian. Gleise (1945:22) estimated the population of these doves at 300 on Tinian in 1945. From the remarks of Stott (1947:526), we may assume that the population at Saipan is in no immediate danger of extinction.

A comparison of specimens from the Marianas with those from the Philippines reveals no significant difference between the two. Bonaparte described the dove in the Marianas as new, naming it Streptopelia gaimardi. The name Turtur prevostianus has been used by some authors to denote the dove in the Marianas, but this was through error as explained by Salvadori (1893:410). This name refers to a dove found on Marianne, an island of the Seychelles in the Indian Ocean.

=Gallicolumba canifrons= (Hartlaub and Finsch)

Palau Ground Dove

Phlegoenas canifrons Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, p. 101. (Type locality, Pelew Islands.)