EN
Black-backed Thornbill Ramphomicron dorsale



Justification

Justification of Red List Category
This species is considered Endangered because it occupies a very small range, within which it has become apparent that suitable habitat is severely fragmented owing to deforestation, extensive burning and over-grazing. The impoverished state of previously suitable habitat in some areas necessitates urgent work to study this species and its threats.

Population justification
This species's population size has not been estimated, but it was described as 'uncommon' by Stotz et al. (1996).

Trend justification
The species's population is suspected to be in decline owing to severe and ongoing habitat loss and degradation. The likely rate of decline is unknown, but could be rapid or very rapid, and more research is required.

Distribution and population

Ramphomicron dorsale is endemic to the Sierra Nevada de Santa Marta in north-eastern Colombia (del Hoyo 1999). It is known from three sites, two of which are the source of historical records only (C. Olaciregui in litt. 2012). The population size has not been quantified, but it is believed to be in decline owing to the continued loss of and damage to the species's habitats.

Ecology

This species occurs on the edges of humid montane forest, elfin forest and páramo, from 2,000 m to the snow-line at 4,600 m (del Hoyo 1999). It is thought to breed in the timberline-páramo ecotone (Fundación ProAves 2011). It appears to forage in all strata, feeding on the nectar of Ericaceae, Erythrina species, Lobeliaceae, Melastomataceae, Puya species, Rubiaceae and Salvia species, and taking insects in the air or gleaning them from leaves. It moves to lower elevations in May-June (del Hoyo 1999).

Threats

Forest clearance for agriculture is severe and has reached this species's elevation range (O. Cortes in litt. 2011), whilst trees in some areas are unsustainably cut for firewood (N. Krabbe in litt. 2010). The state of páramo and the timberline-páramo ecotone in parts of the species's range is described as disastrous (Fundación ProAves 2011). Extensive and regular burning (N. Krabbe in litt. 2010, Fundación ProAves in litt. 2011) and heavy livestock grazing are causing severe damage to the timberline zone (Fundación ProAves 2011). The species is also potentially affected by climate change (Fundación ProAves 2011).

Conservation actions

Conservation Actions Underway
It is recorded annually in the c.770-ha El Dorado Bird Reserve, but many of these are probably wandering immatures (Fundación ProAves 2011). Since 2006, the foundation has been carrying out a programme to eradicate exotic pines and replace them with native trees, with the support of the local environment authority (C. Olaciregui in litt. 2012). The species may be afforded some protection by the Sierra Nevada de Santa Marta National Park (del Hoyo 1999).

Conservation Actions Proposed
Conduct research into the species's ecology and life history.  Estimate area of occupancy (C. Olaciregui in litt. 2012). Confirm presence at sites where the species was historically recorded (C. Olaciregui in litt. 2012). Carry out surveys to obtain a population estimate. Monitor trends in the population. Monitor the extent and condition of habitat. Raise awareness of the species's plight amongst local people. Increase the area of suitable habitat that receives adequate protection. Encourage sustainable livestock and land management practices.

Identification

9-10cm. Male has very short, slightly decurved black bill; upperparts velvety black, postocular spot white, uppertail-coverts purplish-bronzy on tips; olive green gorget, rest of underparts dark grey mixed with rufous, and with green spots; tail quite long, deeply forked, purplish-black, with outer pair of rectrices broadened. Female shining green above, uppertail-coverts as in male; buffy-white below with some green spots; tail similar to male's but shorter, with outer pairs of rectrices tipped white.

Acknowledgements

Text account compilers
Butchart, S., Ekstrom, J., Sharpe, C J, Taylor, J.

Contributors
Olaciregui , C., Krabbe, N., Cortés, O.


Recommended citation
BirdLife International (2020) Species factsheet: Ramphomicron dorsale. Downloaded from http://www.birdlife.org on 15/08/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/08/2020.