Measurements.—Measurements are listed in [table 42].
Weights.—The author (1948:68) records the weights of five adult males as 10.5-12.5 (11.9), and those of two adult females as 11.4 and 12.0 grams.
Specimens examined.—Total number, 64 (33 males, 22 females, 9 unsexed), as follows: Mariana Islands, USNM—Guam, 26 (Jan. 21, March 16, May 21, 29, 30, June 1, 3, 14, 24, 26, July 10, 12, 13, 20, 23, Aug. 30); AMNH—Guam, 38 (Jan., Feb., March, July, Aug.).
Nesting.—The writer (1948:68) records a nest containing one egg found by Muennink at Guam near Mt. Santa Rosa on May 7, 1945. The nest was in a bamboo stump approximately six feet from the ground. The egg hatched on about May 21. Seale (1901:50) reports on a nest and egg taken in the period from May to July. The NAMRU2 party obtained a female on March 15 with an enlarged gonad. Strophlet (1946:539) observed a pair of broadbills building a nest on September 20, 1945; it was completed on October 4 and was approximately seven feet above the ground. Hartert (1898:33) reports on a nest taken at Guam on February 14, 1895.
Molt.—As shown by the specimens examined, molt begins in June or July.
Food habits.—The stomach of a bird obtained on January 21, 1945, contained one unidentified bug (Hemiptera) and several parts of other insects.
Remarks.—The Micronesia Broadbill at Guam is not a common bird, and like its relative Rhipidura rufifrons is an inhabitant of forested areas, especially those containing brushy undercover. It is an active bird, although less conspicuous than Rhipidura. The birds were found as singles or in pairs. The pair of birds which had a nest at the west base of Mount Santa Rosa in May, 1945, allowed the observers to approach closely to them. The birds are easily attracted by squeaking sounds. There is considerable variation in the amount of cinnamon coloring on the breasts of adult birds.
The Micronesian Broadbill at Guam was first discovered by Quoy and Gaimard, who called it "Moucherolle à gorge rouge." Kittlitz (1836:304) evidently records two species of flycatchers from Guam, which he calls Muscicapa. I judge these birds to be Myiagra and Rhipidura. It was not until 1881 that Oustalet recognized this bird to be new. The first large series of specimens was obtained by Marche for the Paris Museum and was reported on by Oustalet (1895:194). Marche collected 12 skins in August and September, 1887, and 4 additional skins in February, 1889.