This was the most common of all the spiderhunters, and was found at all localities. It was readily taken in mist nets. Unlike most birds, these spiderhunters become quite agitated in nets, and within a few minutes usually strangle themselves.
From October 16 through November 11, I took several specimens 12 miles north of Kalabakan, but only one in breeding condition. On November 15, I moved 12 miles back to Kalabakan from an elevation of 600 feet to an elevation of 50 feet. As can be seen from the specimen-data, nearly all the females then collected either had nests with eggs or were approaching oviposition. The specimens were all taken in nets in an area approximately 200 feet square. On November 20 at the Brantian Estate a bird sitting on a branch six inches up in secondary forest jumped down to the ground and fed on unknown material.
Arachnothera crassirostris (Reichenbach): Thick-billed Spiderhunter.—Specimen, 1: Cocoa Research Station: ♀, 14.8 gm., August 9, 1962, MCT 2746.
This spiderhunter was recorded on the basis of one specimen and one sight record. One seen in secondary forest would dart out from its perch on a limb, hover near the end of a branch, and then return to its perch. No flowers were visible and I assumed that the bird was catching insects.
Arachnothera flavigaster (Eyton): Greater Yellow-eared Spiderhunter.—Specimens, 9: Cocoa Research Station: ♀ imm., 36.3 gm., August 21, 1962, MCT 2789; ♀ imm., 38.4 gm., August 21, 1962, MCT 2790; ♀, 38.4 gm., August 22, 1962, MCT 2795; ♀ brood patch, largest ova 2 mm., November 27, 1962, MCT 3330; ♂, November 28, 1962, MCT 3359; ♂ testis 7 × 6 mm., November 29, 1962, MCT 3379; ♂, November 30, 1962, MCT 3395; ♀, April 27, 1963, ADG 66; ♀, April 27, 1963, ADG 67.
This species was met with only at Quoin Hill, where it was common around the abaca and wild bananas. The primary diet seemed to be pollen, nectar, and spiders. I found it easy to differentiate from the next species in the field (see below).
Arachnothera chrysogenys harrissoni Deignan: Lesser Yellow-eared Spiderhunter.—Specimens, 4: Cocoa Research Station: ♀, 23.5 gm., August 21, 1962, MCT 2788; ♂, April 27, 1963, ADG 68; ♂, April 30, 1963, ADG 92; ♂, May 27, 1963, ADG 113.
I observed this species at Quoin Hill only once, but Garcia took three specimens at the same locality. He labels his specimens as taken in primary forest. I never saw the species there and took my one specimen in the abaca, where the bird was eating spiders, nectar, and pollen. The chief characters distinguishing this species from A. flavigaster were the tuft of yellow feathers on the side of the head and the narrow eye ring in A. chrysogenys.
Arachnothera affinis pars Riley: Gray-breasted Spiderhunter.—Specimens, 27: Cocoa Research Station: ♂, 27.2 gm., August 13, 1962, MCT 2771; ♀, 22.2 gm., August 13, 1962, MCT 2772; ♀ imm., 21.1 gm., August 13, 1962, MCT 2773; ♂, 29.2 gm., August 13, 1962, MCT 2774; ♂, 27.0 gm., August 21, 1962, MCT 2791; ♂, 26.6 gm., August 21, 1962, MCT 2792; ♂, April 27, 1963, ADG 65; ♀ imm., May 1, 1963, ADG 99; ♂, June 12, 1963, ADG 126; ♂, June 20, 1963, ADG 154-B. 12 mi. N Kalabakan: ♀, October 15, 1962, MCT 3046; ♀, October 24, 1962, MCT 3139. Cocoa Research Station: ♂ testis 3 × 2 mm., November 27, 1962, MCT 3327; ♀, November 27, 1962, MCT 3328; ♀, November 27, 1962, MCT 3329; ♀, November 27, 1962, MCT 3338; ♂ testis 5 × 4 mm., November 27, 1962, MCT 3339; ♂, November 28, 1962, MCT 3363; ♀, November 28, 1962, MCT 3364; ♂, November 28, 1962, MCT 3365; ♀, November 28, 1962, MCT 3366; ♀, November 29, 1962, MCT 3390; ♂ testis enlarged, November 29, 1962, MCT 3391; ♀?, November 29, 1962, MCT 3392; ♂, December 1, 1962, MCT 3393; ♂, December 2, 1962, MCT 3429; ♂, November 30, 1962, MCT 3442.
This bird was fairly common at Quoin Hill in the abaca and wild bananas and, at Kalabakan, in primary forest. Its feeding habits are the same as those of the preceding species. The order of abundance of the spiderhunters is probably best shown by the number of each species taken: Arachnothera longirostris, 58; A. affinis, 27; A. flavigaster, 9; A. chrysogenys, 4; A. crassirostris, 1.