# Apo sunbird

The Apo sunbird (Aethopyga boltoni) is a species of bird in the sunbird family Nectariniidae. It is endemic to the island of Mindanao in the Philippines.It is found in tropical moist montane forests above 1,500 meters above sea level.

## Description and taxonomy

Ebird describes it as a "A small, localized bird of mid- to high-elevation montane forest on Mindanao. Has a long, curved bill, a gray head, yellow underparts and rump, an olive back and wings, and a white-tipped tail. Male has a narrow pale yellow throat stripe from the bill to the chest bordered with dark gray, a greenish-blue tail, an orange smudge down from the middle of the chest, and a small red patch in front of the shoulder. Female has a pale gray throat. Similar to Gray-hooded Sunbird, but Apo has a yellow rather than a white belly. Voice includes a rapid pulsing series of “chip!” notes and a high-pitched upslurred “chuuuuuit!”

## Taxonomy

The Apo sunbird was formally described in 1905 by the American ornithologist Edgar Alexander Mearns from specimens collected from Mount Apo on the island of Mindanao, Philippines. He coined the binomial name Aethopyga boltoni.
Three subspecies are recognised:
* A. b. boltoni Mearns, 1905 – east-central, east Mindanao
* A. b. malindangensis Rand & Rabor, 1957 – west Mindanao; slightly brighter and has more orange on the male's breast than the nominate
* A. b. tibolii Kennedy, RS, Gonzales & Miranda, 1997 – south Mindanao; narrow pale yellow stripe, paler colors, lesser extent of orange on males and restricted to the shoulder
Aethopyga boltoni tibolii is separated as its own species called the Tboli sunbird under The Clements Checklist of Birds of the World.
This species also included the Lina's sunbird until 1997 when it was described as a separate species named in honor of Lina Rabor, Dioscoro S. Rabor's wife who would assist expeditions.

## Ecology and behavior

This species is pressumed to feed primarily on nectar but will also supplement its diet with insects especially when it is nesting.This species is found singly, in pairs and forms mixed species flocks with other forest birds.
The Apo sunbird has been recorded breeding in January-July. Only 2 nests have been found in 1904 and 1995 have been described. The nests were suspended high in the air, roughly 24 meters. The dimensions of the nest were 8 x 16 cm, with a side entrance of 3 cm, and were constructed of moss, spider eggs, and insect cases.

## Habitat and conservation status

The Apo sunbird is a bird local to the island of Mindanao in the Philippines. It can be found in mountainous areas in the western and central parts of the island, specifically, Mount Apo, Mount Kitanglad, and Mount Malindang. Its natural habitat is in montane rainforest above 1,500 meters above sea level for boltoni and malindangensis but much lower with the lowest record at just 800 meters above sea level.
The IUCN has classified the species as Least Concern but was formerly listed as near threatened. Despite its limited range, it is said to be locally common. The Apo sunbird occurs at similar densities to its kin, the lovely sunbird at 49.1 individuals/km$^2$. 10% of the mapped area is occupied, which places the number of individuals at 37,000. This would be equal to about 25,000 mature individuals. However, the Apo sunbird is thought to live at slightly lower densities than its counterparts, so it is believed 25,000 mature individuals live in the mountainous region of Mindanao.
As it occurs in rugged and inaccessible mountains, this has allowed a large portion of its habitat to remain intact. However, there it is still affected by habitat loss through deforestation, mining, land conversion and slash-and-burn - just not to the same extent as lowland forest.