Dusky Sunbird (Cinnyris fuscus)

Cover image: Dusky Sunbird by Desire Darling – Kamanjab Rest Camp, Namibia –  BirdPix No. 13649

Identification

The Dusky Sunbird is a medium sized sunbird This species is sexually dimorphic, the breeding males are more colourful than females.

Breeding males are distinctive and easily recognisable. The head, back, throat and chest are glossy black and the belly is white. The tail is blackish, with a slight blue iridescence. Breeding males also have orange pectoral tufts, but these are seldom visible unless the bird is excited or displaying.

Non-breeding males and males in eclipse plumage resemble females and have grey-brown upperparts. They sometimes show a few blackish iridescent feathers. The undersides are whitish with a variable, glossy black patch or stripe on the throat and breast.

Females have plain greyish-brown heads and upperparts. The underparts, from the chin to the vent are white to off-white. The underparts contrast with the greyish-brown cheeks and upperparts. The tail is blackish.

Juveniles are similar to adult females, but have browner upper parts and their underparts are washed washed yellow. Juvenile males have variable blackish feathering on the throat.

Breeding males are unmistakable, but females are more problematic to identify. They are most likely to confused with the female White-bellied Sunbird (Cinnyris talatala) or the female Southern Double-collared Sunbird (Cinnyris chalybeus). The former has a faintly streaked (not plain) breast, and the latter has a darker grey-brown throat and breast and lacks the contrast between the upper and undersides. Females of these species are best identified by the accompanying male.

Status and Distribution

The Dusky Sunbird is Locally common and near-endemic to southern Africa. It occurs throughout the arid and semi-arid arid western parts of South Africa. It ranges north through south-western Botswana (avoiding the central Kalahari), throughout most of Namibia and into Angola along the arid coastal plain.

The Dusky Sunbird is scarce in in southern Kalahari and the Little Karoo, with occasional records south of the Cape Fold Mountains and to the south towards the west coast to Cape Town.

The Dusky Sunbird is not threatened and its choice of arid habitats makes it relatively safe from human interference.

Habitat

The Dusky Sunbird’s preferred habitat is rocky outcrops with taller vegetation, as well as drainage line scrub or woodland in the succulent and Nama Karoo. It also inhabits semi-arid coastal plains with sand dunes. It favours rocky habitats or broken ground, possibly because flowering succulents such as Aloes and crassulas are more common in such areas.

It avoids the ‘sand sea’ of the central Namib Desert, but occurs elsewhere within the Namib Desert, provided there is some tall vegetation. The Dusky Sunbird also readily enters gardens and orchards.

Behaviour

The Dusky Sunbird is mainly a sedentary resident and does not show any regular seasonal movements. As with most birds of arid country, it is nomadic in response to the availability of food, which in turn, is dependant on rainfall. The Dusky Sunbird is capable of moving large distances in search of resources. During drought periods it irrupts into neighbouring, more mesic regions such as the coastal regions of the Western Cape, and into the North West Province.

The Dusky Sunbird is an active, restless species and is usually encountered singly or in pairs. Larger groups may aggregate at major nectar sources where it often associates with other sunbird species like Scarlet-chested Sunbird (Chalcomitra senegalensis), White-bellied Sunbird (Cinnyris talatala) and Southern Double-collared Sunbird (Cinnyris chalybeus). The flight is fast and direct, but not as erratic as in other sunbirds.

The Dusky Sunbird generally probes for nectar while perched but may also hover for brief moments, often to snatch insects out of spider webs. They move quickly from flower to flower. The diet consists mostly of nectar and is supplemented with arthropods, especially spiders and small insects like flies, moths, caterpillars, bugs and beetles. Insect prey is mostly gleaned from flowering plants but they also hawk insects out of the air. Important food plants include Vachelia (Acacia) species, various aloes including Kraal Aloe (Aloe claviflora) and the Quiver-tree (Aloidendron dichotoma), also Leafless Wormbush/Black Storm (Cadaba aphylla), Crassula species, mesembryanthemums, honey-thorns (Lycium spp) and mistletoes (Loranthaceae). Dusky Sunbirds also feed on the nectar of a range of alien and garden plants such as Wild Tobacco (Nicotiana glauca). Drinks water on occasion, mostly on on warm days.

The Dusky Sunbird has a long breeding season from August to March but breeding can take place at any time of the year. This is indicative of opportunistic breeding linked to rainfall. If rains come early, some males will attempt to breed while still in eclipse plumage. Males aggressively defend their territories which, on occasion, may lead to fighting. The nest is built entirely by the female while the male remains nearby to defend his territory.

The nest is oval, with a side-top entrance. It is constructed out of dry grass, plant fibres, bark and dry leaves. The nest is bound together with spider web and it is lined with soft seed fibres or animal hair. The nest is usually placed in a low shrub 40 to 90 cm above the ground. Females sometimes build several preliminary nests before egg laying starts. Some nests can be abandoned before laying if conditions become unfavourable. Two to three eggs are laid per clutch. The incubation period lasts just 13 days and all incubation is performed by the female. Nestlings are fed by both parents but they are brooded by the female only. The nestling period lasts around 13 days.

Dusky Sunbirds are double-brooded in high-rainfall years. This sunbird is sometimes parasitised by Klaas’s Cuckoo (Chrysococcyx klaas).

Further Resources

Species text adapted from the first Southern African Bird Atlas Project (SABAP1), 1997.

The use of photographs by Cobus Elstadt, Desire Darling, Gerald Gaigher, Jason Boyce, Johan Van Rooyen, Lappies Labuschagne, Maans Booysen and Pamela Kleiman is acknowledged.

Virtual Museum (BirdPix > Search VM > By Scientific or Common Name).

Other common names: Namakwasuikerbekkie (Afrikaans); Souimanga fuligineux (French); Roethoningzuiger (Dutch); Rußnektarvogel (German); Beija-flor-sombrio (Portuguese).

A list of bird species in this format is available here.

Recommended citation format: Tippett RM 2024. Dusky Sunbird Cinnyris fuscus. Biodiversity and Development Institute. Available online at https://thebdi.org/2024/06/04/dusky-sunbird-cinnyris-fuscus/

Bird identification, birding