This species seemed to prefer secondary forest or cocoa as a habitat and was an uncommon bird at Quoin Hill.
Nectarinia sperata (Linnaeus): Van Hasselt's Sunbird.—Fred Dunn saw a male in secondary forest near the Cocoa Research Station.
Nectarinia jugularis (Linnaeus): Yellow-breasted Sunbird.—This sunbird was abundant in the coconut palms at Siamil Island. The species was observed also at exotic flowering plants in Tawau.
Nectarinia hypogrammica hypogrammica S. Müller: Purple-naped Sunbird.—Specimens, 10: Cocoa Research Station: ♀, November 27, 1962, MCT 3334: ♂, July 7, 1963, ADG 167. 12 mi. N Kalabakan: ♂ testis 3 × 5 mm., October 14, 1962, MCT 3035; ♂, October 15, 1962, MCT 3047; ♂, October 23, 1962, MCT 3133; ♂, October 24, 1962, MCT 3145; ♂, November 2, 1962, MCT 3203; ♀, November 15, 1962, MCT 3287. Oil Palm Research Station: ♀, August 16, 1963, ADG 247; ♂, August 27, 1963, ADG 262.
This common species of secondary forest at Quoin Hill seems to prefer spiders and various insects for food. I saw one bird removing dead leaves from a tree and picking out the spiders that had taken over the curled leaves as shelters. I also saw birds of this species hover before spiderwebs and remove the spiders.
A specimen taken on November 15, 1962, was in heavy molt.
Aethopyga mystacalis (Temminck): Scarlet Sunbird.—Specimen, 1: Cocoa Research Station: ♂, 6.0 gm., September 12, 1962, MCT 2903.
This specimen was molting from a drab to an adult type male plumage. I saw this species only one other time at Quoin Hill, but on December 26 I saw two males feeding among epiphytic plants in the moss forest above Tenom. The condition of the specimen's plumage prevented its identification to subspecies (presumably A. m. temmincki).
Aethopyga siparaja (Raffles): Yellow-backed Sunbird.—Specimens, 3: Tawau: ♂ testis 5 × 5 mm., September 2, 1962, MCT 2861. Tiger Estate: ♂, October 11, 1962, MCT 2999. Oil Palm Research Station: ♀, August 13, 1963, ADG 231.
This sunbird was common around flowers at Kalabakan and Brantian Estate.
Unfortunately, I lack enough specimens to make a subspecific identification. The specimen from Tawau differs from A. s. siparaja, however, only in having darker wings; it closely resembles the type and the series that Oberholser used when describing A. s. ochrapyrrha.
Arachnothera longirostris buttikoferi van Oort: Little Spiderhunter.—Specimens, 58: Cocoa Research Station: ♂, 16.2 gm., August 13, 1962, MCT 2777; ♂, 15.6 gm., August 22, 1962, MCT 2796; ♂ testis 6 × 4 mm., 16.0 gm., September 13, 1962, MCT 2913; ♀, December 1, 1962, MCT 3399; ♂ testis 4 × 3 mm., December 2, 1962, MCT 3431; ♂, November 27, 1962, MCT 3347; ♀, November 27, 1962, MCT 3348; ♂, November 28, 1962, MCT 3366; ♂, November 28, 1962, MCT 3367; ♀, November 28, 1962, MCT 3368; ♀, November 28, 1962, MCT 3369; ♂, November 28, 1962, MCT 3370; ♀, November 28, 1962, MCT 3371; ♂, November 28, 1962, MCT 3372; ♂, November 29, 1962, MCT 3386; ♂, December 1, 1962, MCT 3397; ♂, December 1, 1962, MCT 3398; ♀, December 2, 1962, MCT 3430; ♀?, November 30, 1962, MCT 3443; ♀, April 26, 1962, ADG 60; ♂, April 27, 1963, ADG 70; ♂, April 27, 1962, ADG 73; ♂, April 18, 1963, ADG 78; ♂, April 28, 1963, ADG 80; ♂, April 29, 1963, ADG 86; ♂, April 29, 1963, ADG 87; ♂, April 30, 1962, ADG 93. 12 mi. N Kalabakan: ♀, October 16, 1962, MCT 3050; ♂, October 16, 1962, MCT 3051; ♂ testis 4 × 2 mm., October 18, 1962, MCT 3073; ♀, October 17, 1962, MCT 3064; ♂ testis 7 × 5 mm., October 19, 1962, MCT 3079; ♀, October 19, 1962, MCT 3093; ♂, October 21, 1962, MCT 3120; ♂, October 23, 1962, MCT 3134; ♂ testis enlarged, October 25, 1962, MCT 3150; ♂ testis 7 × 5 mm., October 26, 1962, MCT 3156; ♀, October 28, 1962, MCT 3173; ♂, November 2, 1962, MCT 3204; ♂, November 4, 1962, MCT 3209; ♂ testis 5 × 4 mm., November 4, 1962, MCT 3210; ♂ testis 2 × 1 mm., November 6, 1962, MCT 3214; ♀, November 11, 1962, MCT 3252. Kalabakan: ♀, November 15, 1962, MCT 3278; ♀ 2 eggs in oviduct, ovary enlarged, brood patch, November 15, 1962, MCT 3279; ♀ brood patch, two collapsed follicles, November 15, 1962, MCT 3280; ♂ testis 7 × 6 mm., November 15, 1962, MCT 3281; ♀ brood patch, egg in oviduct, largest ovum 6 mm., November 15, 1962, MCT 3286; ♂ testis 7 × 6 mm., November 16, 1962, MCT 3290; ♂ testis 3 × 2 mm., November 16, 1962, MCT 3294; ♀, November 16, 1962, MCT 3295; ♂ testis 6 × 3 mm., November 17, 1962, MCT 3297; ♂ testis 5 × 5 mm., November 17, 1962, MCT 3298; ♀, November 17, 1962, MCT 3299. 5.5 mi. SW Tenom: ♀, December 26, 1962, MCT 3538. Gum-Gum: ♂, October 4, 1963, ADG 290; ♀, October 5, 1963, ADG 294; ♀, October 5, 1963, ADG 295.