This babbler was common in small groups at Quoin Hill. Whitehead (1893:227) states that the species "frequents the true forest near the ground." I observed these babblers only in sub-canopy trees, at least 30 feet above the ground. Smythies (1960:419) stated that he had never seen this species in the forest undergrowth.
Stachyris erythroptera bicolor (Blyth): Red-winged Tree Babbler.—Specimens, 11: Cocoa Research Station: ♂ testis 2 × 1 mm., 13.4 gm., July 24, 1962, MCT 2654; ♀ imm., 13.0 gm., August 28, 1962, MCT 2832; ♀, 12.5 gm., August 28, 1962, MCT 2833; ♂, December 2, 1962, MCT 3432; ♀, December 2, 1962, MCT 3433. 12 mi. N Kalabakan: ♂, October 10, 1962, MCT 2995; ♂, November 6, 1962, MCT 3215; ♂, November 7, 1962, MCT 3218. 5.5 mi. SW Tenom: ♂ testis 3 × 1 mm., December 18, 1962, MCT 3463. Ulu Balung Cocoa Estate: ♂, July 10, 1963, ADG 184; ♂, July 17, 1963, ADG 206.
This species was seen most often in primary forest undergrowth, but occasionally as high as 10 feet up in small trees. I saw it also in and around brush piles in secondary forest. The one specimen from 5.5 mi. SW Tenom was taken in the moss forest. MCT 2833 was in heavy molt on the wings, head, and body.
Stachyris rufifrons sarawacensis Chasen: Hume's Tree Babbler.—Specimen, 1: Cocoa Research Station: ♂ testis 4 × 3 mm., November 28, 1962, MCT 3358.
There was no comparative material in the U. S. National Museum where I studied the specimen but it fits Chasen's original description of S. r. sarawacensis. H. G. Deignan (in Peters et al., 1964:303) considered this subspecies doubtfully distinct from S. r. poliogaster.
The specimen was taken at a height of one and one-half feet in a mist net set along a path. The bird was caught when it attempted to cross the path from a patch of heavy undergrowth to a patch on the other side. Mary Norman observed them at Kalabakan (Smythies, 1963:281) in saplings. They should probably be considered birds of the understory.
Alcippe brunneicauda (Salvadori): Brown Quaker Babbler.—Specimens, 22: Cocoa Research Station: ♂ imm., 14.4 gm., August 20, 1962, MCT 2781; ♀, 14.9 gm., September 6, 1962, MCT 2877; ♀, September 25, 1962, MCT 2957; ♀, November 28, 1962, MCT 3361; ♀, November 28, 1962, MCT 3362; ♂, November 28, 1962, MCT 3376; ♂, November 28, 1962, MCT 3378; ♂ testis 5 × 3 mm., December 1, 1962, MCT 3410; ♂, December 2, 1962, MCT 3435; ♂, November 30, 1962, MCT 3440; ♂, November 30, 1962, MCT 3441. 12 mi. N Kalabakan: sex?, November 1, 1962, MCT 3194; ♂, November 11, 1962, MCT 3243; ♂, November 11, 1962, MCT 3245; ♂, November 11, 1962, MCT 3247; ♂, November 11, 1962, MCT 3248; ♂, November 12, 1962, MCT 3261; ♀, November 13, 1962, MCT 3267; ♀, November 10, 1962, MCT 3306. 5.5 mi. SW Tenom: ♀, December 22, 1962, MCT 3501; ♀, December 22, 1962, MCT 3502; ♀, December 22, 1962, MCT 3503.
Birds of this species were common in primary forest at the three localities listed under "specimens." They travel in small, loose flocks, calling as they move through the forest. Periodic calling, interspersed with periods of silence, was characteristic of the species; vocalization of this sort may function in maintaining the unity of the well spaced flock.
Yuhina castaniceps everetti (Sharpe): Chestnut-headed Yuhina.—Specimens, 14: 5.5 mi. SW Tenom: ♀, December 19, 1962, MCT 3468; ♂ testis 6 × 3 mm., December 23, 1962, MCT 3512; ♂ testis 7 × 3 mm., December 23, 1962, MCT 3513; ♂ testis 6 × 3 mm., December 24, 1962, MCT 3520; ♀, December 24, 1962, MCT 3521; ♂ testis 5 × 3 mm., December 24, 1962, MCT 3523; ♂ testis 6 × 3 mm., December 24, 1962, MCT 3524; ♀, December 24, 1962, MCT 3525; ♀, December 24, 1962, MCT 3526; ♂ testis 6 × 3 mm., December 24, 1962, MCT 3527; ♂ testis 6 × 3 mm., December 28, 1962, MCT 3542; ♂ testis 6 × 3 mm., December 28, 1962, MCT 3543.
I saw several flocks of this species in moss forest at a point 5.5 miles southwest of Tenom. Some were observed going into cavities in the moss, where they apparently caught insects. They sometimes did this simultaneously, in several places on the same tree.
Yuhina zantholeuca brunnescens (Sharpe): White-bellied Yuhina.—Specimens, 4: 12 mi. N Kalabakan: ♀, October 12, 1962, MCT 3010; sex?, November 1, 1962, MCT 3193; sex?, December 22, 1962, MCT 3500; ♂ testis 7 × 4 mm., December 23, 1962, MCT 3519.