Monarcha takatsukasae (Yamashina)

Tinian Monarch

Monarcharses takatsukasae Yamashina, in Takatsukasa and Yamashina, Dobutsu. Zasshi, 43, 1931, p. 485. (Type locality, Tinian.)

Monarcha takatsukasae Yamashina, Tori, 7, 1932, p. 400 (Tinian); Hand-list Japanese Birds, rev., 1932, p. 175 (Tinian); Hand-list Japanese Birds, 3d ed., 1942, p. 195 (Tinian); Mayr, Birds Southwest Pacific, 1945, p. 296 (Tinian); Downs, Trans. Kansas Acad. Sci., 49, 1946, p. 100 (Tinian).

Geographic range.—Micronesia: Mariana Islands—Tinian.

Characters.—Adult male: Forehead, lores, eyering, auriculars, and underparts rufous, chin paler; under tail-coverts white; crown and nape dark slate-gray; back reddish-brown; rump white; wing and tail dark brown, outer edges of first three primaries white, tail with white tips, more broadly tipped on outer tail feathers; outer edges of scapulars and secondaries buffy but tips more whitish, forming two wing bars; under wing-coverts whitish; bill slate-blue, tip pearl; feet dark slate; iris dark brown.

Adult female: Resembles adult male, but slightly smaller and crown more brownish.

Immature: Resembles adult, but base of bill lighter and underparts paler.

According to the original description by Yamashina, M. takatsukasae resembles closely the immature M. godeffroyi of Yap in coloration; however, the Tinian Monarch has a shorter wing.

Measurements.—Measurements are listed in [table 41].

Table 41. Measurements of Monarcha takatsukasae

Table 41. Measurements of Monarcha takatsukasae

Number and SexWingTailFull CulmenTarsus
6 males706818.022.0
(67-72)(65-70)(17.5-19.0)(21.0-23.0)
10 females676717.222.5
(65-68)(64-69)(17.0-19.0)(21.7-23.0)

Specimens examined.—Total number, 20 (10 males, 10 females), as follows: Mariana Islands, USNM—Tinian, 10 (Oct.); AMNH—Tinian, 9 (Sept.); KMNH—Tinian, 1 (Sept.).

Nesting.—Yamashina (1932a:400, 401) records two nests of the Tinian Monarch. He writes of one nest containing two eggs taken at Churo, Tinian, on January 29, 1932, that was "hung on a fork of an upward pointing branch of a road side tree commonly called 'Oba' 1.5 m. high from the ground in a forest.... The ground color of the egg shells is white. The spots are pale reddish-brown and distributed all round the surface like small dots, being concentrated especially round the larger end." Another nest containing three eggs was found on January 29, 1932. Yamashina writes that the eggs measure 20.5 x 15, 21 x 15, and 18 x 15 mm. In describing these nests Yamashina notes, "The shape of the two nests mentioned above is like a deep cup. The outer layer of them is made chiefly of dead leaves, fibers, cotton, wools and moss, and the inner layer of fine stems and fibers only."

Downs (1946:101) writes that a nest found near Lake Hagoi at Tinian on August 31, 1945, "was about three feet from the ground carefully woven into the framework of a triangular crotch.... It was composed exteriorly of small leaves, scattered white feathers, and heavy grass; interiorly of grasses only." In the nest he found a young bird which "was black-skinned, with ugly white quills and a few short dark feathers on its tail and wings. The back feathers were rusty brown as were the tufted head feathers." Marshall (1949:219) assumes that this bird breeds all year.

Molt.—Birds taken by Coultas in September are in fresh plumage.

Remarks.—The Tinian Monarch is known only from Tinian, where it was described in 1931 by Yamashina. Downs (1946:100-103) presents a detailed account of this bird as he saw it in 1945. He found it living in brushy woodlands where other birds, including Rhipidura rufifrons, were observed. From his description, the actions and food-catching behaviors of this bird must be much like those of Rhipidura. Gleise (1945:220) estimated the population of these birds to be 40 to 50 in 1945.