Purple-backed sunbeam (Aglaeactis aliciae)
|Spanish:||Colibrí de Alicia|
|Size||Head-body length: 12 – 13 cm (2)|
|Weight||7.3 – 8.3 g (2)|
Classified as Endangered (EN) on the IUCN Red List (1) and listed on Appendix II of CITES (1).
Restricted to just a single location in western Peru, the purple-backed sunbeam is an attractive hummingbird with a striking iridescent plumage (4). A patch of shimmering amethyst is conspicuous on the rump and lower back, contrasting sharply with the dark brown plumage on the upper back and head, and the white breast, throat, chin and lores. The tail feathers are a reddish-bronze, with golden-green coverts and a white tip. The bill is short, straight and black. The plumage of the female purple-backed sunbeam is highly variable, and may be identical to the males, or the iridescent parts may be reduced, or completely absent. Juveniles are very similar in appearance to the adult females, but have buffy spots on the throat, chin and belly (2).
The purple-backed sunbeam is restricted to a very small area in the upper drainage of the Maranon River in La Libertad region, west Peru. Although most abundant around the village of El Molina, recent surveys obtained reports from throughout much of its historical range, on both the east and west banks of the Maranon River, and in the upper Chusgon Valley. The full extent of the species’ range may not be greater than 35.5 kilometres in length, although, not all areas of suitable habitat have been surveyed, and unconfirmed sightings are reported from the Ancash region, 140 kilometres to the south of the La Libertad population (4) (5).
The purple-backed sunbeam inhabits the understory of montane shrubland containing Alnus trees, between 2,900 and 3,600 metres above sea level (4).
The unique shoulder structure of hummingbirds allows the wings to beat extremely quickly in a figure-of-eight motion, enabling the birds to maintain a hovering motion whilst feeding, with up to 200 wing beats per second. Owing to this energy demanding behaviour, hummingbirds feed almost exclusively on the nectar, carbohydrate-rich sugar secretions of plants, feeding from as many as 1,000 to 2,000 flowers each day. Hummingbirds also have the highest oxygen requirement of any vertebrate, and as a result, have a breathing rate of up to 500 breaths per minute, and uniquely structured lungs. These physiological adaptations have allowed hummingbirds to occupy a vast array of habitats and altitudes throughout the Americas (6).
Little is known about the specific biology of the purple-backed sunbeam. However, it has been observed feeding on the orange-red flowers of parasitic mistletoe on Alnus trees, using its specialised bill and long, sensitive tongue to extract the nectar (5) (6). In common with most other hummingbirds, the purple-backed sunbeam is probably solitary, and aggressively territorial (6). Specimens of males with enlarged testes collected in June, suggest that the breeding season of the purple-backed sunbeam is around August to September (5). Males will mate with several females, but have no involvement in raising the offspring, with the female solely responsible for nest-building, incubation, and rearing of the chicks. The nest of a purple-backed sunbeam has never been seen, but it is most likely constructed close to a nectar source, on a branch sheltered from direct sunlight. In most hummingbirds, only two oval-shaped eggs are laid, which are incubated for around 16 to 19 days, and the chicks will remain in the nest for between 23 to 26 days after hatching (6).
Restricted to a very small area that is heavily populated, the greatest threat to the purple-backed sunbeam is the conversion of Alnus dominated shrubland to Eucalyptus plantations, as this removes the parasitic mistletoe upon which it feeds (4). The species’ restricted range also makes it vulnerable to the effects of chance natural events, such as disease and drought, while the low population number, estimated at less than 1,000 birds, may mean that it has a very low genetic diversity. Historically the Maranon River landscape has undergone high levels of habitat conversion for cultivation, and much of the original natural habitat has been lost, or continues to be degraded. Cattle ranching, logging and firewood collecting has removed much of the forest habitat, while oil extraction is a potential future problem (4) (7).
The Maranon valley, home to the purple-backed sunbeam, is an area of high conservation importance, as its isolation and unique habitats, has resulted in a large degree of endemism. A total of twenty two bird species are endemic to the valley, and as a result it has been designated as a Birdlife International Endemic Bird Area (EBA) (7). The Maranon valley has also been designated as part of the Maranon-Alto Mayo Conservation corridor, as it supports a high number of conservation priority areas. The American Bird Conservancy has been working to analyse the distribution of rare bird species within the Maranon valley, and identify the areas and habitats that require protection. A wide array of conservation strategies have been proposed, including strict protected area status, sustainable conservation, and community owned nature reserves. However, at present only 0.1 percent of the Maranon valley has any legal protection and these measures need to be applied urgently (8).
There are no known specific conservation measures in place for the purple-backed sunbeam. However, further surveys are required to evaluate the species’ ecological requirements, so that the suitability of Eucalyptus plantations can be assessed, and the awareness of the species’ plight must be increased amongst local residents (4).
For more information on the conservation of the Maranon valley, see:
The American Bird Conservancy:
Birdlife International EBA Factsheet:
The Hummingbird Society:
This information is awaiting authentication by a species expert, and will be updated as soon as possible. If you are able to help please contact:
- Coverts: small feathers concealing the bases of larger flight feathers, usually on the wings or tail.
- Endemic: a species or taxonomic group that is only found in one particular country or geographic area.
- Endemism: the degree to which a species or taxonomic group is confined to a single region.
- Incubation: the act of incubating eggs, that is, keeping them warm so that development is possible.
- Lores: The space between the beak and the eye on birds.
- Parasitic: describes organisms that derive their food from, and live in or on, another living organism at the host’s expense.
- Testes: Male reproductive glands responsible for the production of male germ cells or sperm.
IUCN Red List (January, 2010)
- del Hoyo, J., Elliott, A. and Sargatal, J. (1994) Handbook of the Birds of the World. Vol. 5: Barn-Owls to Hummingbirds. Lynx Edicions, Barcelona.
CITES (January, 2010)
BirdLife International (January, 2010)
- Birdlife International. (2002) Threatened Birds of the Americas. Birdlife International, Cambridge, UK.
- Perrins, C. (2009) The Encyclopedia of Birds. Oxford University Press, Oxford.
Birdlife International EBA factsheet (January, 2010)
The American Bird Conservancy (January, 2010)