Cameroon sunbird

The Cameroon sunbird (Cyanomitra oritis) is a species of bird in the family Nectariniidae. It is native to montane forests of Cameroon, Nigeria, and Equatorial Guinea, including the island of Bioko.^[2] It inhabits high-altitude forests and feeds primarily on nectar and insects.^[3] The species shows marked sexual dimorphism, with males displaying a metallic blue breast and duller females, and is known to make seasonal altitudinal movements.^[3] The species is classified as Least Concern by the International Union for Conservation of Nature (IUCN), although its population trend is decreasing due to habitat loss.^[4]

The vocalization of the Cameroon sunbird consists of a 'sequence of rapid, well spaced whistles described as "tiu tiu tiwu tiwu tiu tiu.'"^[2] Breeding has been recorded that eggs are laid from March-April and then from November-December. They build pear-shaped nests that are made from grass, moss, rootlets lined with fibre, silk-cotton, and dry grass.^[3] Cameroon sunbirds are considered non-migratory but make altitude movements. On Mount Cameroon, individuals have been observed descending to lower elevations between June and September.^[3]

Males have an upper breast metallic steel-blue with violet reflections, with their hindneck and the rest of their body being olive-green. The bill is sharp, curved and black matching their legs.^[3] The eyes have a dark brown iris with a bright, pale blue eyering.^[3] Females differ from males, lacking pectoral tufts. Females appear olive-brown. Their underparts are yellow-tinged and duller than males.^[3] Females have a shorter, less curved bill.^[3] As juveniles, they appear duller above and below. The metallic areas are instead brown or grey with a bright yellow belly. The throat and breast are steel-blue rather than deep purplish-blue.^[3] Immatures have a shorter bill and appear darker olive. Head gloss is more greenish, with the metallic blue continuing from the hindneck farther down the breast.^[3]

The Cameroon sunbird occurs in montane forests of Cameroon, Nigeria and Equatorial Guinea, including the island of Bioko.^[2] Montane forests are "high-altitude, biodiversity-rich cloud forests found above 1,600m on volcanic peaks, characterized by a dense, humid canopy" of many different species of trees.^[5] This bird primarily feeds on small insects and nectar. They forage individually or in pairs, and occasionally in large groups near flowering trees.^[3]

The Cameroon sunbird is not a concern according to the IUCN Red List evaluation.^[4] This species is classified under the Least Concern category. The global population is unquantified but is stable. The population trend has been noted as declining.^[6] Some species of sunbirds live between 2-8 years, Cameroon sunbirds have an average generation length of 2.7 years.^[6] Habitat loss caused by agricultural expansion, logging, and infrastructure development is considered the primary threat to the species.^[4]