Peters (1934:348, 349) recognizes three other subspecies from the Pacific area: G. a. rothschildi Hartert from Laysan, Lisiansky, and Krusenstern islands; G. a. candida (Gmelin) from "the Carolines east to Christmas Island and south to the Tonga and Society Islands"; and G. a. royana Mathews from Norfolk and the Kermadec Islands. Birds from Revilla Gigedo, Cocos and Clipperton islands, although geographically isolated, are placed in G. a. candida. On the basis of a critical study of specimens at hand, the populations in the Pacific fit into three groups. Small birds, G. a. candida, are found in the North Pacific from the Bonins and Marianas east to Wake and the Hawaiian Chain and south to the Marshall, Phoenix, Christmas and the Fanning islands (see figure 12). Larger birds, G. a. pacifica, are found in the Central Pacific and South Pacific from the Carolines in the west southeastward through Melanesia and eastward through Samoa, to the Tuamotus and Easter to Cocos, Clipperton, and Revilla Gigedo islands. In the Southwest Pacific, at Norfolk and the Kermadec Islands, a longer-winged population occurs; it is separable as G. a. royana. The measurements of these birds are given in table 24.
The measurements indicate that there is a gradient in size from small in the north to large in the south; however, there is a definite separation in average measurements—ten millimeters in length of wing and four millimeters in length of exposed culmen—between the two populations which are designated as G. a. candida and G. a. pacifica. In studying material from Micronesia and the Hawaiian Islands, I (1948:57) pointed out the similarities between birds of the Marianas and the Hawaiians and separated these from terns found in the Caroline Islands. The systematic position of the White Tern in the Gilbert and Ellice islands will remain in doubt until specimens are available for examination.
G. a. royana is provisionally retained as the name for the Fairy Tern of the Kermadecs and Norfolk Island; there is considerable overlap in measurements between G. a. royana and G. a. pacifica. Measurements have given evidence of the degrees of structural resemblance of the White Terns of the different islands, but it is not certain that the groupings made on this basis are natural; more data is needed on ecology and life history. Of particular importance is to learn whether these birds fly regularly from island to island. On the basis of eleven months of rather continuous observation in Micronesia, I suspect that the White Tern has little tendency to make inter-island migrations. This might account for the differences in size in the populations at Guam in the Marianas (G. a. candida) and at Ulithi in the Carolines (G. a. pacifica) where only approximately 400 miles of open water separate the two islands. The occurrence of the distinct G. a. microrhyncha in the Marquesas may be accounted for by such nonmigratory behavior. Mayr (1945a:27), however, is of the opinion that White Terns found in the Bismarck Archipelago, the Solomons, Santa Cruz and New Hebrides islands may not breed there, which is another way of saying that they are migrants. Swarth (1934:221) and Murphy (1936:1268) record the wandering of the White Tern to the Galapagos Islands, probably from breeding grounds at Cocos Island. Swarth suggests that the tern is not established at the Galapagos because of the presence of colder water in the area. Murphy (1936:1166) is of the opinion that the South Atlantic White Terns are sedentary, but reports evidence of pelagic migration in the Pacific at the Kermadecs. The fact that G. alba is restricted in its distribution to widely separated groups of islands in tropical and subtropical areas of the South Atlantic, Indian and Pacific oceans may indicate that the birds at one time had a more extensive range than at present, probably including even coastal regions of the continents and large continental islands.
Gygis alba pacifica (Lesson)
White Tern
Sterna pacifica Lesson, Ann. Sci. Nat., 4, 1825, p. 101. (Type locality, Society Islands, Paumotu Islands, and Bora Bora.)
Sterna alba Kittlitz, Kupfertaf. Naturgesch. Vögel, 3, 1833, p. 28 (Carolinen); idem, Obser. Zool., in Lutké, Voy. "Le Séniavine," 3, 1836, pp. 286, 299, 308 (Ualan, Lougounor, Ouleai).
Gygis candida Hartlaub, Archiv f. Naturgesch., 18, 1852, p. 137 (Carolinen); Hartlaub, Journ. f. Ornith., 1854, p. 168 (Carolinen); Kittlitz, Denkw. Reise russ. Amer. Micron. und Kamchat., 1, 1858, p. 382, 2, 1858, pp. 39, 60 (Ualan); Gray, Cat. Birds Trop. Is. Pacific Ocean, 1859, p. 59 (Caroline Islands); Saunders (part), Cat. Birds British Mus., 25, 1896, p. 149 (Pelew, Carolines); Takatsukasa and Kuroda, Tori, 1, 1915, p. 51 (Ruk, Pelew).
Gygis alba Finsch and Hartlaub, Fauna Centralpolynesiens, 1867, p. 233 (Carolinen); Hartlaub, Proc. Zool. Soc. London, 1867 (1868), p. 832 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1868, pp. 9, 118 (Pelew); Finsch and Hartlaub, Journ. f. Ornith., 1870, p. 140 (Pelew); Hartlaub and Finsch, Proc. Zool. Soc. London, 1872, pp. 90, 114 (Pelew, Uap, Ualan); Gräffe, Journ. Mus. Godeffroy, 2, 1873, p. 123 (Yap); Finsch, Journ. Mus. Godeffroy, 8, 1875, pp. 6, 43 (Palau); idem, Journ. Mus. Godeffroy, 12, 1876, pp. 18, 40 (Ponapé); idem, Proc. Zool. Soc. London, 1877 (1878), p. 782 (Ponapé); idem, Journ. f. Ornith., 1880, pp. 295, 309 (Ponapé, Kuschai); idem, Proc. Zool. Soc. London, 1880, p. 577 (Ruk); idem, Ibis, 1881, pp. 105, 106, 109, 115, 246, 247 (Kushai, Ponapé); Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, pp. 299, 330, 353 (Mortlock, Nukuor, Ruk); Finsch, Mitth. Ornith. Ver. Wien, 1884, p. 52 (Kuschai); Wiglesworth (part), Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 78 (Pelew, Uap, Luganor, Nukuor, Ruk, Ponapé, Ualan); Oustalet (part), Nouv. Arch. Mus. Hist. Nat. Paris, (3), 8, 1896, p. 58 (Palaos, Carolines); Baker (part), Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 57 (Peleliu, Ulithi, Truk, Kusaie).
Gygis alba kittlitzi Hartert, Katalog Vogelsamml. Senckenb., 1891, p. 237 (Type locality, Ulea = Wolea); idem, Novit. Zool., 7, 1900, p. 10 (Ruk); Dubois, Syn. Avium, 2, 1904, p. 1020 (Carolines); Mathews (part), Birds Australia, 2, 1912, p. 443 (Carolines); Ridgway (part), Bull. U. S. Nat. Mus., 50, pt. 8, 1919, p. 559 (Carolines); Kuroda (part), Avifauna Riu Kiu, 1925, p. 193 (Carolines); Hand-list Japanese Birds (part), rev., 1932, p. 196 (Pelew, Yap, Wolea, Luganor, Ruk, Ponapé, Kusaie); Yamashina (part), Tori, 10, 1940, p. 678 (Babelthuap).
Gygis albus kittlitzi Kuroda (part), in Momiyama, Birds Micronesia, 1922, p. 50 (Pelews, Yap, Wolea, Luganor, Nukuor, Ruk, Ponapé, Kusaie).
Leucanous albus kittlitzi Mathews (part), Syst. Avium Australasianarum, 1, 1927, p. 143 (Carolines).
Gygis alba candida Peters, Check-list Birds World, 2, 1934, p. 349 (Carolines); Hand-list Japanese Birds (part), 3d ed., 1942, p. 219 (Babelthuap, Koror, Angaur, Yap, Wolea, Truk, Lukunor, Nukuoro, Ponapé, Kusaie).
Geographic range.—Central and southern Pacific from Carolines southeast through Melanesia and east through Samoa to Tuamotus, Easter to Cocos and Clipperton (see figure 12). In Micronesia: Palau Islands—Angaur, Peleliu, Garakayo, Koror, Babelthuap, Kayangel; Caroline Islands—Yap, Ulithi, Wolea, Truk, Lukunor, Ponapé, Kusaie.
Characters.—Resembles G. a. candida, but size larger, wing length of adult males and females 236-253 (245); length of exposed culmen 38-44 (42).
Measurements.—Measurements are listed in table 24.
Specimens examined.—Total number, 36 (22 males, 12 females, 2 unsexed), as follows: Palau Islands, USNM—Peleliu, 1 (Sept. 1); AMNH—exact locality not given, 1 (Nov. 13);-Caroline Islands, USNM—Ulithi, 12 (Aug. 14, 15, 16, 20, 21)—Truk, 1 (Dec. 13); AMNH—Truk, 7 (Mar. 8, May 7, June 8, Nov. 11, 26)—Ponapé, 1 (undated)—Kusaie, 10 (Jan., Feb., March 20-30, April 1-10); MCZ—Yap, 3 (Jan. 13).
Nesting.—The NAMRU2 party learned that in May and June, 1945, several young White Terns were seen at Asor, Ulithi Atoll, by service personnel. These young were observed in breadfruit trees within a recreational area; the presence of the service personnel seemingly had little disturbing effect on the terns. At Bulubul, another island of this atoll, a downy young was obtained on August 22. Hartert (1900:10) reports that eggs of the White Tern were found on the ground and in forks of branches of trees at Truk in June.
Food Habits.—The author (1948:58) reports that stomachs of birds taken at Ulithi and Peleliu contained fish, insects and marine crustaceans. Probably the birds feed to a large extent along the edge of the tidal reef. They almost certainly obtain food also on the islands as indicated by the presence of insects in stomach contents; this is not surprising since the birds frequent woodland habitats.
Remarks.—Gygis alba is one of the most characteristic birds in Micronesia. It is seemingly more numerous at the coral atolls than at the high, volcanic islands. At the latter islands the birds prefer the coastal coconut grove environment. At Pau and Bulubul, two small islands in the Ulithi Atoll, the writer counted approximately 100 birds on August 21, 1945. Kittlitz was the first to publish an account of these birds in the Caroline Islands. Tetens, Peters, Semper and Kubary reported their presence in the Palaus. No doubt, these terns attract the attention of every traveler in the islands owing to their conspicuously white beauty and their seemingly friendly behavior toward man. Their habit of hovering in small flocks close over the head of the observer is indeed spectacular.
Columba livia Gmelin
Blue Rock Pigeon
Columba domestica [Greek: b] livia Gmelin, Syst. Nat., 1, pt. 2, 1789, p. 769. (No type locality = Europe.)
Columba livia Bryan, Guam Rec., vol. 13, no. 2, 1936, p. 24 (Guam); Marshall, Condor, vol. 51, 1949, p. 221 (Tinian).
Geographic range.—Europe and Asia Minor. Introduced to many parts of the world. In Micronesia: Mariana Islands—Guam, Tinian.
Remarks.—In 1945, the NAMRU2 party observed pigeons about the towns on Guam, particularly at the town of Inarajan. Bryan (1936:24) writes that the birds were introduced by the United States Navy and Marine Corps at Guam; the stock originating from escaped carrier pigeons. Marshall (1949:221) records this bird from Tinian.
Ptilinopus porphyraceus ponapensis (Finsch)
Crimson-crowned Fruit Dove
Ptilinopus ponapensis Finsch, Proc. Zool. Soc. London, 1877 (1878), p. 779. (Type locality, Ponapé.)
Ptilinopus? fasciatus Finsch, Journ. Mus. Godeffroy, 12, 1876, pp. 18, 37 (Ponapé).
Ptilopus fasciatus Elliot, Proc. Zool. Soc. London, 1878, p. 536 (Ponapé); Tristram, Cat. Birds, 1889, p. 44 (Ponapé).
Ptilopus ponapensis Schmeltz, Verhandl. Ver. nat. Unterhaltung Hamburg, 1877 (1879), pp. 178, 179 (Ponapé); Finsch, Proc. Zool. Soc. London, 1880, p. 576 (Ruk, Ponapé); idem, Journ. f. Ornith., 1880, pp. 291, 303 (Ponapé); idem, Proc. Zool. Soc. London, 1880, p. 578 (Ruk, Ponapé); idem, Ibis, 1881, pp. 113, 115 (Ponapé); Wiglesworth, Ibis, 1891, p. 583 (Ponapé, Ruk); idem, Abhandl. und Ber. Zool. Mus. Dresden, no. 6, 1890-1891 (1891), p. 50 (Ponapé, Ruk); Salvadori, Cat. Birds British Mus., 21, 1893, p. 93 (Ponapé, Ruk); Oustalet, Nouv. Arch. Mus. Hist. Nat., Paris, (3), 7, 1895, p. 222 (Ponapé); Nehrkron, Kat. Eiers., 1899, p. 180 (Ruk); Dubois, Syn. Avium, 2, 1904, p. 736 (Ruck, Ponapé); Reichenow, Die Vögel, 1, 1913, p. 354 (Ruk, Ponapé); Takatsukasa and Kuroda, Tori, 1, 1915, p. 52 (Ruk, Ponapé); Wetmore, in Townsend and Wetmore, Bull. Mus. Comp. Zoöl., 63, 1919, p. 189 (Uala, Ponapé).
Ptilinopus ponapensis Schmeltz and Krause, Ethnogr. Abth. Mus. Godeffroy, 1881, p. 353 (Ruk); Hartert, Novit. Zool., 7, 1900, p. 7 (Ruk, Ponapé); Seale, Occ. Papers Bernice P. Bishop Mus., 1, 1901, p. 42 (Ponapé); Matschie, Journ. f. Ornith., 1901, p. 113 (Ruck, Ponapé); Mathews, Syst. Avium Australasianarum, 1, 1927, p. 32 (Ponapé); Bequaert, Mushi, 12, 1939, pp. 81, 82 (Ponapé); Mayr. Proc. 6th Pacific Sci. Congr., 4, 1939 (1941), p. 204 (Ponapé); Bequaert, Occ. Papers Bernice P. Bishop Mus., 16, 1941, pp. 266, 290 (Ponapé).
Ptilinopus Ponapensis Christian, The Caroline Islands, 1899, p. 357 (Ponapé).
Ptilinopus ponepensis ponapensis Kuroda, in Momiyama, Birds Micronesia, 1922, p. 57 (Ponapé, Ruk); Yamashina, Tori, 7, 1932, p. 408 (Ponapé); Hand-list Japanese Birds, rev., 1932, p. 190 (Ponapé, Ruk); Peters, Check-list Birds World, 3, 1937, p. 31 (Ruk, Ponapé); Hand-list Japanese Birds, 3d ed., 1942, p. 213 (Ponapé, Truk).
Ptilinopus porphyraceus ponapensis Ripley and Birckhead, Amer. Mus. Novit., no. 1192, 1942, p. 7 (Ruk, Ponapé); Mayr, Birds Southwest Pacific, 1945, p. 289 (Truk, Ponapé); Baker, Smithson. Misc. Coll., vol. 107, no. 15, 1948, p. 59 (Truk).
Geographic range.—Micronesia: Caroline Islands—Truk, Ponapé. Characters.—Adult male: A green fruit dove with forehead, anterior lores and crown near "pansy purple," faintly margined with yellow; occiput, sides of head, neck, upper breast grayish-green with bifid feathers of midbreast more olivaceous; chin and midthroat light yellow; breast, sides and tibia green; midpart of lower breast dark bluish-green, tinged with dark purple; lower abdomen, vent, and undertail yellow, under tail-coverts deeper yellow tinged with orange; upper parts dark green; wings metallic green on outer webs and tips, inner secondaries and some posterior scapulars with purple spots near tips; primaries and secondaries edged on outer webs with yellowish; underwing gray with yellow edges on hind, under wing-coverts; upper side of tail metallic green with terminal, broad yellow band; under side of tail gray; bill lead-colored, feet wine-brown, iris whitish to pale brown. Adult female resembles adult male, but slightly smaller and duller.
Immature: Resembles adult, but entirely green with yellow edgings on feathers and lacking crimson crown and colored breast patch.
Measurements.—Measurements of subspecies of P. porphyraceus in Micronesia are presented in table 25.
Subspecies Number Wing Exposed
culmenTarsus P. p. ponapensis 12 males
137 (133-141) 14 (13-15) 25 (24-27) 11 females
133 (126-137) 14 (13-15) 25 (24-26) P. p. hernsheimi 6 males
134 (130-138) 13 (12-14) 25 (24-26) 5 females
127 (125-130) 13 (12-13) 25 (24-25) P. p. pelewensis 10 males
133 (131-134) 15 (13-15) 25 (23-26) 4 females
133 (130-138) 15 (14-15) 24 (23-24)