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Little Woodstar Chaetocercus bombus
BirdLife is updating this factsheet for the 2016 Red List
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This species has a large range, but it is severely fragmented, and only a fraction is likely to be occupied. It qualifies as Vulnerable because the dearth of recent records suggests that the population may now be small, comprised of very small subpopulations, and declining significantly owing to rapid rates of deforestation.

Taxonomic source(s)
del Hoyo, J.; Collar, N. J.; Christie, D. A.; Elliott, A.; Fishpool, L. D. C. 2014. HBW and BirdLife International Illustrated Checklist of the Birds of the World. Barcelona, Spain and Cambridge UK: Lynx Edicions and BirdLife International.
SACC. 2006. A classification of the bird species of South America. Available at: #

Taxonomic note

Acestrura bombus Sibley and Monroe (1990, 1993), Acestrura bombus Stotz et al. (1996), Acestrura bombus Collar and Andrew (1988), Acestrura bombus Collar et al. (1994), Acestrura bombus BirdLife International (2004), Acestrura bombus BirdLife International (2000)

6-7 cm. Tiny hummingbird with typical woodstar plumage pattern. Male has dark bronzy blue-green upperparts and belly. Buffy pectoral-band and postocular line meet. Rosy gorget. Forked tail. Female has similarly coloured upperparts, but underparts are cinnamon, with tawny sides and vent, and rounded tail has black subterminal bar. Immature like female. Both sexes have a straight black bill. Similar spp. Most other male woodstars have white pectoral-band and postocular line. Voice a series of rapid chit-cheet and chit-chit-cheet calls.

Distribution and population
Chaetocercus bombus has historically been recorded from central Peru (seven departments from La Libertad and Huánaco in the south), on both slopes of the Andes north through Andean and west-central lowland Ecuador (14 provinces) to south-west Colombia (Nariño), where it was recently discovered and is thought to be seasonal (Salaman and Mazariegos 1998). It was once common, but has declined significantly, and very few have been recorded in recent years (Fjeldså and Krabbe 1990), although several were reported recently from northern Peru (T. Marks in litt. 2003). During the 1990s, it was considered uncommon in Machalilla National Park, Manabí, Ecuador (Parker and Carr 1992), and common in the newly established Loma Alta Ecological Reserve (7.5 km2), Guayas, Ecuador (Becker and López Lanús 1997), but recent reports relate to single individuals (e.g. at least one at Dos Mangas Communal Reserve, Guayas in 2005 [Ágreda 2007]) and it is not known to be present regularly or in large numbers anywhere in the country (Gurney 2006).

Population justification
The population is estimated to number 2,500-9,999 mature individuals based on an assessment of known records, descriptions of abundance and range size. This is consistent with recorded population density estimates for congeners or close relatives with a similar body size, and the fact that only a proportion of the estimated Extent of Occurrence is likely to be occupied. This estimate is equivalent to 3,750-14,999 individuals, rounded here to 3,500-15,000 individuals.

Trend justification
A moderate and on-going population decline is suspected on the basis of continuing losses and fragmentation of the species's preferred habitat.

It is found between sea-level and 3,050 m, in humid evergreen forest and, more commonly, in the transitional zone between dry and wet forests. It appears to make seasonal or occasional movements, perhaps in response to continental rainfall patterns or El Niño Southern Oscillation events(Salaman and Mazariegos 1998).

Below 900 m, the rate of deforestation in western Ecuador over the period 1958-1988 was 57% per decade (Dodson and Gentry 1991). High levels of habitat loss are continuing, at least in unprotected areas, and will soon remove almost all remaining lowland forest if effective action is not taken urgently. In higher parts of the species's range, rates of habitat destruction are not as great, but logging and conversion of land for agriculture and plantations are causing loss and degradation of forest (Dodson and Gentry 1991, Dinerstein et al. 1995).

Conservation Actions Underway
CITES Appendix II. It occurs in Río Ñambí Community Nature Reserve (Nariño), Río Palenque Reserve (Pichincha), Loma Alta Ecological Reserve, Podocarpus National Park (J. F. Freile in litt. 2000) and Machalilla National Park. Machalilla is the largest of the four, but lacks effective protection. Conservation Actions Proposed
Search for the species, especially in parts of its range where habitat remains but where there are few recent records (Peru, central Ecuador, east Andean slopes throughout).

Ágreda, A. E. 2007. Feeding ecology and conservation of Esmeraldas Woodstar Chaetocercus berlepschi in the Chongón-Colonche Hills, western Ecuador. Cotinga: 38-41.

Becker, C. D.; López Lanús, B. 1997. Conservation value of a Garua forest in the dry season: a bird survey in Reserva Ecológica de Loma Alta, Ecuador. Cotinga: 66-74.

Collar, N. J.; Gonzaga, L. P.; Krabbe, N.; Madroño Nieto, A.; Naranjo, L. G.; Parker, T. A.; Wege, D. C. 1992. Threatened birds of the Americas: the ICBP/IUCN Red Data Book. International Council for Bird Preservation, Cambridge, U.K.

Dinerstein, E.; Olson, D. M.; Graham, D. J.; Webster, A. L.; Primm, S. A.; Bookbinder, M. P.; Ledec, G. 1995. A conservation assesssment of the terrestrial ecoregions of Latin America and the Caribbean. World Bank, Washington, D.C.

Dodson, C. H.; Gentry, A. H. 1991. Biological extinction in western Ecuador. Annals of the Missouri Botanical Garden 78: 273-295.

Fjeldså, J.; Krabbe, N. 1990. Birds of the high Andes. Apollo Books, Copenhagen.

Gurney, M. 2006. Identification of Little Woodstar Chaetocerus bombus in Ecuador. Neotropical Birding: 38-41.

Parker, T. A.; Carr, J. L. 1992. Status of forest remnants in the Cordillera de la Costa and adjacent areas of southwestern Ecuador (Rapid Assessment Program). Conservation International, Washington, D.C.

Salaman, P. G. W.; Mazariegos, H. L. A. 1998. The hummingbirds of Nariño, Colombia. Cotinga 10: 30-36.

Further web sources of information
Detailed species account from the Threatened birds of the Americas: the BirdLife International Red Data Book (BirdLife International 1992). Please note taxonomic treatment and IUCN Red List category may have changed since publication.

Detailed species account from the Threatened birds of the Americas: the BirdLife International Red Data Book (BirdLife International 1992). Please note, taxonomic treatment and IUCN Red List category may have changed since publication.

Explore HBW Alive for further information on this species

Recuento detallado de la especie tomado del libro Aves Amenazadas de las Americas, Libro Rojo de BirdLife International (BirdLife International 1992). Nota: la taxonomoía y la categoría de la Lista Roja de la UICN pudo haber cambiado desde esta publicación.

Search for photos and videos, and hear sounds of this species from the Internet Bird Collection

Text account compilers
Benstead, P., Harding, M., Isherwood, I., Pilgrim, J., Sharpe, C J, Stuart, T., Symes, A.

Freile, J., Marks, T.

IUCN Red List evaluators
Butchart, S., Symes, A.

Recommended citation
BirdLife International (2016) Species factsheet: Chaetocercus bombus. Downloaded from on 22/10/2016. Recommended citation for factsheets for more than one species: BirdLife International (2016) IUCN Red List for birds. Downloaded from on 22/10/2016.

This information is based upon, and updates, the information published in BirdLife International (2000) Threatened birds of the world. Barcelona and Cambridge, UK: Lynx Edicions and BirdLife International, BirdLife International (2004) Threatened birds of the world 2004 CD-ROM and BirdLife International (2008) Threatened birds of the world 2008 CD-ROM. These sources provide the information for species accounts for the birds on the IUCN Red List.

To provide new information to update this factsheet or to correct any errors, please email BirdLife

To contribute to discussions on the evaluation of the IUCN Red List status of Globally Threatened Birds, please visit BirdLife's Globally Threatened Bird Forums.

Additional resources for this species

ARKive species - Little woodstar (Chaetocercus bombus) 0

Key facts
Current IUCN Red List category Vulnerable
Family Trochilidae (Hummingbirds)
Species name author Gould, 1871
Population size 2500-9999 mature individuals
Population trend Decreasing
Distribution size (breeding/resident) 147,000 km2
Country endemic? No
Links to further information
- Additional Information on this species