Part 62

TABLE 24. MEASUREMENTS OF Gygis alba FROM THE PACIFIC AREA

Column headings:

A: No. B: Wing C: Longest tail feather D: Shortest tail feather E: Exposed culmen F: Depth Culmen G: Tarsus

======================+====+=======+=======+=====+=====+=======+========= LOCATION | A | B | C | D | E | F | G ----------------------+----+-------+-------+-----+-----+-------+--------- Gygis alba candida | | | | | | | (Gmelin) | | | | | | | | | | | | | | Japan, Bonins | 4 | 238 | 109 | 65 | 36 | | | | | | |34-38| | | | | | | | | Mariana Islands | 35 | 237 | 111 | 69 | 38 | 9.0 | 13.0 | |227-246| 98-120|61-75|36-41| |12.0-14.0 | | | | | | | Wake Islands | 10 | 236 | 109 | 69 | 38 | | 13.0 | |232-243|101-118|64-77|37-41| |13.0-14.0 | | | | | | | Hawaiian Islands | 36 | 235 | 109 | 68 | 37 | 8.5 | 13.0 | |220-246|102-118|64-74|33-40|8.0-9.0|12.0-14.0 | | | | | | | Marshall Islands | 4 | 234 | 111 | 71 | 39 | | | |231-238|107-115|70-73|38-40| | | | | | | | | Phoenix, Howland, | | | | | | | Hull, Canton Islds.| 8 | 238 | 107 | 70 | 39 | 8.5 | 14.0 | |237-240|101-116|64-76|37-41| | | | | | | | | Fanning, Washington,| | | | | | | Christmas Islands | 19 | 238 | 107 | 68 | 38 | 8.0 | 13.5 | |227-242| 97-119|65-72|37-42|7.5-9.0|12.0-15.0 +----+-------+-------+-----+-----+-------+--------- Totals |116 | 236 | 109 | 69 | 38 | 8.5 | 13.0 | |220-246|107-120|61-77|33-42|7.5-9.0|12.0-15.0 | +=======+=======+=====+=====+=======+========= Gygis alba pacifica | | | | | | | (Lesson) | | | | | | | | | | | | | | Caroline, Palau | | | | | | | Islands | 33 | 245 | 116 | 73 | 42 | 8.5 | 13.5 | |236-253|112-125|67-76|38-44| |13.0-13.5 | | | | | | | Bismarck Arch., | | | | | | | Solomon Islands | 12 | 247 | 116 | 74 | 42 | | | |242-256|105-129|68-78|39-45| | | | | | | | | Samoa, Wallis, Fiji,| | | | | | | Tonga, Niue Islands| 20 | 247 | 115 | 71 | 42 | | | |239-254|110-127|67-78|39-44| | | | | | | | | Line, Danger Islands| 13 | 245 | 115 | 73 | 41 | | | |238-252|107-118|69-78|39-42| | | | | | | | | Cook,Austral Islands| 29 | 247 | 114 | 73 | 42 | | | |241-255|104-124|65-78|40-45| | | | | | | | | Society Islands | 37 | 249 | 113 | 71 | 42 | 8.5 | 13.5 | |241-257|107-126|62-76|40-45|8.0-9.0|12.0-14.0 | | | | | | | Tuamotu Arch |118 | 245 | 114 | 72 | 42 | | | |236-252|107-127|62-82|38-46| | | | | | | | | Rapa, Bass Rocks, | | | | | | | Oeno, Henderson, | | | | | | | Ducie, Pitcairn, | | | | | | | Easter Islands | 54 | 247 | 113 | 73 | 41 | | | |240-255|106-126|63-84|40-45| | | | | | | | | Clipperton, Cocos | | | | | | | Islands | 10 | 245 | 115 | 72 | 40 | 8.5 | 13.5 | |240-253|110-120|71-73|38-43|8.5-9.5|13.0-14.0 +----+-------+-------+-----+-----+-------+--------- Totals |326 | 246 | 114 | 72 | 42 | 8.5 | 13.5 | |236-257|104-129|62-84|38-46|8.0-9.5|12.0-14.0 | +=======+=======+=====+=====+=======+========= Intergrades between | | | | | | | G. a. microrhyncha| | | | | | | and G. a. pacifica| 9 | 237 | 105 | 74 | 38 | 7.5 | 13.0 | |230-247| 93-122|67-89|36-41|7.0-8.0|12.0-14.0 | | | | | | | Gygis alba | | | | | | | microrhyncha | 55 | 218 | 78 | 64 | 36 | 6.5 | 12.0 | |211-235| 72-96 |60-75|32-39|6.0-8.0|11.0-12.5 | | | | | | | Gygis alba royana | | | | | | | Mathews | | | | | | | | | | | | | | Norfolk Islands | 16 | 250 | 113 | 73 | 42 | | | |242-257|105-124|68-79|41-44| | | | | | | | | Kermadec Islands | 12 | 251 | 115 | 75 | 43 | | | |244-255|110-121|71-81|40-46| | +----+-------+-------+-----+-----+-------+--------- Totals | 28 | 250 | 114 | 74 | 42 | | | |242-257|105-124|68-81|40-46| | ----------------------+----+-------+-------+-----+-----+-------+---------

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.