=====================+=====+=========+========+===========+========
| | | Bill | Bill |
SUBSPECIES | No. | Wing | from | from | Tarsus
| | | rictus | nostril |
---------------------+-----+---------+--------+-----------+--------
_G. c. indica_ | 15 | 164 | 27 | 14.4 | 48
| | 158-173 | 24-29 | 13.1-18.1 | 44-50
| | | | |
_G. c. orientalis_ | 3 | 152 | 27 | 13.8 | 45
| | 146-152 | 26-29 | 13.1-14.4 | 44-46
| | | | |
_G. c. lozanoi_ | 11 | 164 | 27 | 14.5 | 50
| | 153-170 | 24-29 | 13.1-15.2 | 45-57
| | | | |
_G. c. guami_ | 11 | 164 | 27 | 14.7 | 49
| | 156-171 | 24-28 | 13.1-16.2 | 47-56
| | | | |
_G. c. sandvicensis_ | 2 | 150-158 | 27 | 13.4 | 52-56
---------------------+-----+---------+--------+-----------+--------
_Weights._--From Guam an adult male weighed 291 grams and an adult
female 256 (Baker, 1948:49).
_Specimens examined._--Total number, 42 (16 males, 22 females, 4
unsexed), as follows: Mariana Islands, USNM--Guam, 5 (Feb. 24, May,
June 5, 7, 18--Tinian, 3 (Oct. 12, 18)--Saipan, 3 (Sept. 28, 30);
AMNH--Guam, 25 (Feb. 21, April 6, July 13, 28, 30, Aug. 1, 3, 6, 7,
13, 19, 23, 30, 31, Sept. 3, 17, Dec. 11--Tinian, 5 (June 11, Sept.
12, 13, 14).
_Nesting._--Hartert (1898:63) reports nests of the Gallinule at
Guam in grass and on swampy ground in December and March. A male
with enlarged gonads was taken by the NAMRU2 party at Guam on June
7. Marshall (1949:219) is of the opinion that this bird breeds all
year.
_Food habits._--Seale (1901:31) found grass, insects, and larvae
in stomachs obtained at Guam.
_Remarks._--The subspecies _G. c. indica_, _G. c. lozanoi_, _G. c.
guami_, and _G. c. sandvicensis_ bear a close resemblance to one another
in size and color. _G. c. guami_ and _G. c. lozanoi_ resemble each other
so closely that it would be difficult to separate unlabeled specimens of
the two subspecies. _G. c. orientalis_ differs from all of the
gallinules in smaller size and darker color. Study of these forms
indicates that the Gallinule has colonized the Marianas from Asia
probably by way of Japan and the Bonin and Volcano islands. The Hawaiian
subspecies is probably of American origin, as pointed out by Mayr
(1943:46), and is not a close relative of the Mariana subspecies. The
fact that these insular subspecies have not undergone much
differentiation does not necessarily mean that they are recent arrivals,
but probably is a reflection of the lack of plasticity of the species;
as a whole the species does not exhibit anywhere a great amount of
geographic variation. A thorough study of all insular populations of
this species (including specimens from the Azores, Seychelles, Réunion,
Mauritus, and the Greater and Lesser Antilles) might reveal the effect
of isolation on the species in general. Its ability to become
established on isolated islands is apparent, although it is indeed
peculiar that the species has not reached the Caroline Islands.
The Gallinule in the Marianas is restricted to fresh water lakes,
marshes and swamps on the islands of Guam, Tinian, Saipan and Pagan.
Coultas (field notes), on visiting the island of Tinian in 1931,
comments that the bird is rare and found at only one lake on the island.
Downs (1946:92) noted the species in 1945, and Joe T. Marshall Jr.
obtained three specimens at Lake Hagoya in October of the same year.
Gleise (1945:220) estimated the population of Gallinules on Tinian in
1945 at 70 individuals. Stott (1947:525) reports that the birds were
abundant at Lake Susupe, Saipan, in 1945. Seale (1901:31) found the
Gallinule to be abundant at Guam in marshes and taro patches. In 1945,
the NAMRU2 party found fairly large populations of the Gallinule in
fresh water marshes and fallow rice paddies at Guam. The greatest
concentration of birds appeared to be in the Agaña Swamp and along the
Ylig River. They seldom ventured out into open water but preferred weedy
edges into which they could suddenly dart when disturbed. It was
interesting to note such wary behavior, for an observer would think that
after the bird had been in an environment virtually devoid of birds of
prey (except for an occasional migrant) for a number of generations, it
would have lost such behaviorisms as a result of the absence of the
selective processes involved in predation.
=Porphyrio porphyrio pelewensis= Hartlaub and Finsch