Black-sided flowerpecker

Appearance

The black-sided flowerpecker is a very small passerine, measuring a mere 8 cm in length. Its weight has not been recorded. Like many flowerpeckers, it is sexually dimorphic; the male is considerably more colourful than the female. The male has glossy blue-black upperparts. His face and the sides of his neck are black, his chin is white, and he has a scarlet throat and breast surrounded by a greyish-black border. His upper flanks and upper belly are dark grey, while his lower flanks are olive, and his lower belly white. His vent and undertail coverts are buffy-yellow. His underwing coverts are white, as are his pectoral tufts. The female has olive-green upperparts and greyish underparts, with buffy flanks, a yellowish rump, a whitish throat and white pectoral tufts. Immature birds are like the female, but more olive-grey below. They are finely streaked with dark from their chin to the breast, and males may show some crimson on the breast. Both sexes have dark brown irises, black bills, and feet variously described as brown or dark grey.

Naming

The female can be confused with the plain flowerpecker, but is larger and has a whiter throat. Her back is also more olive-toned, as compared to the browner-backed plain flowerpecker. All other similar species are allopatric—not found on Borneo—so not likely to be confused.

Status

The International Union for Conservation of Nature rates the black-sided flowerpecker as a species of least concern, though its population has not been quantified. While its numbers are thought to be decreasing, the rate of decline is not thought to be precipitous, and the population is not fragmented. The species is said to be common throughout much of its range. Destruction of forest for oil palm plantations could have a detrimental impact on their numbers. Studies have shown that black-sided flowerpeckers are only found in palm groves in small numbers and within 300 m of the edge of forest; they were not found further into extensive groves.

Habitat

The black-sided flowerpecker is endemic to the montane forests of Borneo. It is typically seen above 1,000 m and as high as 2,540 m in some locations, though it also descends as low as 460 m on two of the island's bigger mountains. There are far more records from Malaysia's states of Sabah and Sarawak than from Indonesia's Kalimantan provinces. It is found in primary and secondary forest, kerangas forest, scrub, and gardens.The black-sided flowerpecker is not known to make any seasonal or altitudinal movements.

Reproduction

Little is known about the breeding ecology of the black-sided flowerpecker. Young have been recorded between November and February, and adults in breeding condition have been found during that period. The nest is made of moss and lined with the pith of tree ferns. Lichens are used to camouflage its surface. The eggs are undescribed.

Food

Like all flowerpeckers, the black-sided flowerpecker is a frugivore. It specializes on mistletoe berries, but also eats other small fruits, including "Medinilla speciosa" berries. Its diet includes seeds, nectar, and various invertebrates. Most of its foraging takes place close to the ground, but it sometimes feeds in the canopy.