NT
Chestnut-bellied Hummingbird Amazilia castaneiventris



Justification

Justification of Red List Category
New information has indicated that the distribution range, availability of habitat, and population size of the species are larger than previously assumed, although it is not clear whether the population size and habitat suitability are still undergoing a decline. The species has therefore been downlisted to Near Threatened.

Population justification
This species has been recorded at a number of new sites in recent years. While still apparently rare in some areas and nowhere abundant, there is a comparatively large area of potentially suitable habitat. Based on the area of the species’s mapped range (4,949km2), a range of recorded population densities (10, 33, 60, 140 and 210 individuals/km2; Cortes-Herrera 2006, D. C. Sabogal in litt. 2009, Peñuela and Archila 2010, Renjifo et al. 2016), and assuming that 11-22% of the range is occupied, the species’s population size is estimated to fall within the range 18,600 – 66,300 individuals, roughly equivalent to 12,400 – 44,200 mature individuals. The national Red List of Colombia estimated the population size at 24,120 individuals (Renjifo et al. 2016), roughly equivalent to 16,080 mature individuals. The population size is therefore here placed in the band 10,000-19,999 mature individuals. However, a recent analysis based on land cover data and a population density model estimated the population size at 117,733 mature individuals (Santini et al. 2019); if this number is confirmed the population size estimate will need to be adjusted accordingly. The species is thought to form at least two subpopulations, since the record in the Serranía de San Lucas (Donegan 2012) is quite distant from the other recent records.

Trend justification
The population trend has not been assessed directly, and it is unclear whether the population size and availability of habitat are declining. A recent analysis of forest loss data from 2000-2012 indicated that forest was lost within the species’s range at a rate equivalent to 1% across three generations (Tracewski et al. 2016). However, this species inhabits forest edges and shrubland, so forest loss may not be a reliable indicator of population change or habitat quality for this species. An analysis of area of habitat and population size based on modelled population densities and remote-sensed land cover data estimated that the species’s area of habitat and population has slightly increased over three generations (Santini et al. 2019). The national Red List of Colombia also estimated an increase in available habitat between 2001 and 2011 (Renjifo et al. 2016). Nevertheless, there may be some habitat degradation, for example from logging, and the population may be impacted by hunting as well as habitat degradation (Renjifo et al. 2016). Therefore, unless new information on the population trend becomes available, the species is precautionarily retained as in decline.

Distribution and population

Amazilia castaneiventris is restricted to the Serranía de San Lucas and the drier parts of the Magdalena Valley, Colombia, with a core range in the Chicamocha, Suarez and Chucuri valleys. Although there are various sites where the species is now found, it is somewhat unpredictable in occurrence (partly influenced by poorly understood seasonal movements) and, at least in the Yariguíes area, not locally abundant. Formerly known from the slopes of the Serranía de San Lucas, where one specimen was taken in 1947 on the east slope of the serranía in Bolívar, this population eluded rapid assessment searches in 1999-2001 (T. Donegan in litt. 2008) but was observed below Santa Cecilia in 2010 (Donegan 2012). Recent records from the río Chucurri basin and La Paz are outside of, and generally more humid than, the dry valley system that forms the core of its range (J. O. Cortes in litt. 2009, D. C. Sabogal in litt. 2009). Extensive survey work by Fundación ProAves has recorded the species at 14 sites. There are historic records from two sites in Santander (in 1962 and 1963), and three in Boyacá including the 1977 specimen from Tipacoque; during 2008-2010 it was found at ProAves's Cerulean Warbler Natural Bird Reserve (Freeman et al. 2012) and recent work has again recorded the species at Tipacoque (J. Zuluaga in litt. 2009). It has now been recorded in eight municipalities including a rediscovered population in the environs of Soatá (Chavez-Portilla and Cortes-Herrera 2006, Parra et al. 2006, Cortes-Herrera et al. 2007) and there was a sighting in 2000 at Villa de Leyva (López-Lanús 2002), although this has not been confirmed, and subsequent visits to Villa de Leyva have failed to find the species (J. Cortes in litt. 2011). Historically, the species was locally common, but trends are difficult to assess owing to a lack of baseline data. The species is often inexplicably rare in apparently suitable habitats and may go unrecorded for periods (J. Zuluaga in litt. 2009). The increase in records of the species owes much to increased observer effort, but also may reflect nomadic movements in recent years linked to flowering events on which the species relies to some degree (J. O. Cortes in litt. 2009).

Ecology

The species inhabits dry valleys and some humid sites at 340-2,200 m, and possibly as low as 120 m in the Serranía de San Lucas (although the species has not been rediscovered at this site since its collection there, despite rapid assessment of the area in 1999-2001 [T. Donegan in litt. 2008]). The species's habitat preferences are somewhat unclear: it is often found in mature gardens with many flowering trees, but rarely in the interior of primary forest (T. Donegan in litt. 2019). Many records come from forest borders, bushy canyons and semi-arid areas vegetated with shrubs and low trees (López-Lanús 2002, T. Donegan in litt. 2019); the species apparently shows a preference for rivers and streams, but is regularly recorded at roadside flowering trees (Cortes-Herrera 2006). Local abundance of this species is apparently affected by the available area of potential habitat (Tricanthera gigantean forest [J. O. Cortes in litt. 2011]). However, it has been suggested that the species is tolerant of habitat degradation, having been recorded in pastures, fruit crops, coffee plantations and xerophytic scrub, where it exploits a wide variety of floral resources, e.g. cactus, guamo (Inga spp.), banana (Musa spp.), and coffee. Yatago (Trychanthera gigantea) flowers seem to be the most important nectar source (J. O. Cortes in litt. 2009, 2010). However, a study about foraging behaviour of this species in one of the driest areas of the Chicamocha canyon showed 15 different types of pollen collected from the species's body, the most common pollen types belonging to Bromeliaceae (Aechmea spp., Catopsis spp., Pitcairnia spp.) and Apocynaceae (Mocoa spp., Himatanthus spp., Temnadenia spp., Odontadenia spp. and Galactophora spp.) This could also shed light on the plants pollinated by this species (Peñuela and Archila 2010). The species seems to be tolerant of human activities; field surveys carried out since 2004 have identified new sites, expanded the range and provided new information that emphasizes the species's adaptability to altered landscapes. For example, the Cerulean Warbler Natural Bird Reserve in San Vicente de Chucuri, Santander, has both shade coffee and primary forest areas; three years of surveys by many groups and individuals across these habitats and area have only ever found Amazilia castaneiventris in shade coffee, hedgerows and pasturelands (never in primary forest), while the species moves between available resources (P. G. W. Salaman in litt. 2008). However, the species may be less tolerant of degraded areas as breeding habitat. The breeding season is December-February (J. O. Cortes in litt. 2009), although a nest was found at the end of April 2009 in the Niceforo’s Wren Natural Bird Reserve (Peñuela and Archila 2010). The species benefits from bee-keeping which promotes the planting of melliferous vegetation used by hummingbirds (Cortes-Herrera 2006). In the driest areas, it seems to undertake nomadic movements/short-distance migration in response to dry conditions when key floral resources may be unavailable (J. O. Cortes in litt. 2009). Project Chicamocha found that territory sizes of Chestnut-bellied Hummingbird remain constant during the year, except in the driest season (November to April) when the species is absent from the Niceforo’s Wren Natural Bird Reserve (Peñuela and Archila 2010). Moreover, some individuals have been observed returning to the same territories after the driest season since 2004 (M. Beltrán pers. comm. 2012).

Threats

The Sagamoso and Lebrija valley systems support large human populations and have long been areas of high agricultural production. Natural habitat has been severely fragmented, and generally replaced by coffee plantations, light woodland and, to a lesser extent, pastures and plantain and sugarcane plantations (the latter is used for biofuel production). Semi-arid habitats are less threatened than humid forest (López-Lanús 2002), but are affected by livestock-grazing and seasonal burning for farming (P. G. W. Salaman in litt. 1999). The Serranía de San Lucas had held the largest tract of intact forest in northwestern South America, but a gold rush began in 1996, and most of the eastern slopes have since been settled, logged and converted for agricultural and coca production (A. Cuervo in litt. 1999, L. Dávalos in litt. 1999, Donegan and Salaman 1999, P. G. W. Salaman in litt. 1999). Mining and cocaine production cause stream pollution (L. Dávalos in litt. 1999, Donegan and Salaman 1999, P. G. W. Salaman in litt. 1999). Immigration is continuing as road and oil pipelines extend into formerly inaccessible areas (A. Cuervo in litt. 1999, P. G. W. Salaman in litt. 1999). Part of the species's range is threatened by flooding by the Sogamoso dam (M. Beltrán pers. comm. 2011). Anecdotal observations suggest that about five individuals per month die from hunting with slingshots (Renjifo et al. 2016).

Conservation actions

Conservation Actions Underway

CITES Appendix II. Considered Endangered at the national level in Colombia (Renjifo et al. 2016). Occurs within ProAves's Niceforo’s Wren Bird Reserve (1,246 ha), Cerulean Warbler Bird Reserve (208 ha) and Helmeted Curassow Bird Reserve (1,939 ha). Project Chicamocha has identified 14 sites that hold the species, concentrating searches primarily in the dry valley system that drains the western slope of the East Andes in Colombia. Fundación Colibrí, Organización Ambiental Ocotea, Fundación Ecodiversidad and Fundación Quincha have worked with Amazilia castaneiventris from 2002 to 2011, with local community involvement at a reserve that supports the species. They intend to start a banding programme to study the species's ecology from December to February. NGOs have conducted activities with school children in elementary schools in four veredas municipalities of Soatá, Tipacoque and Susacon (J. O. Cortes in litt. 2011). Unlike other species found in the Yariguíes, the new National Park there is probably not a significant step forwards for conservation of this species; the only known localities fall outside the Yariguíes National Park boundary. However, there are localities in the relatively new Chicamocha National Park (T. Donegan in litt. 2008). Fundación Conserva is working to establish community based conservation reserves along the Chicamocha canyon.

Conservation Actions Proposed

Determine the species's status in the Serranía de San Lucas, at politically safe historical sites and in protected areas. Research its natural history and habitat preferences, in particular its dependence on Trichanthera gigantea (P. G. W. Salaman in litt. 1999, J. O. Cortes in litt. 2009). Prepare action plans for the conservation of habitat within its range (L. Dávalos in litt. 1999). Protect areas of suitable habitat found to hold the species (L. Dávalos in litt. 1999, T. Züchner in litt. 1999). Raise awareness of conservation issues through educational campaigns (L. Dávalos in litt. 1999). Reforest areas, introducing yatago (Trichanthera) flowers (J. O. Cortes in litt. 2009). Identify migration routes and areas and assign them protection (Parra et al. 2010).

Identification

8.4 cm. Small hummingbird with rufous underparts and tail. Shining reddish-bronze above becoming greyish-buff on rump. Glittering green throat and chest. Rufous-chestnut lower underparts and tail. Small, white leg-puffs. Black, straightish bill with pinkish base to lower mandible. Similar spp. Rufous-tailed Hummingbird A. tzacatl is very similar, but has dingy-grey lower underparts. Voice Gives an excited "grr-grr" when defending a territory against attack from conspecifics or other hummingbirds (Cortes-Herrera 2006).

Acknowledgements

Text account compilers
Isherwood, I., Sharpe, C.J., Benstead, P., Stuart, T., Wheatley, H., Butchart, S., Bird, J., Derhé, M., Hermes, C.

Contributors
Beltrán, M., Chaves Portilla, G., Cortés, O., Cuervo, A., Donegan, T., Dávalos, L., Hernandez-Jaramillo, A., Parra, J., Sabogal, D., Salaman, P.G.W., Stiles, F.G., Zuluaga, J. & Züchner, T.


Recommended citation
BirdLife International (2020) Species factsheet: Amazilia castaneiventris. Downloaded from http://www.birdlife.org on 02/12/2020. Recommended citation for factsheets for more than one species: BirdLife International (2020) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 02/12/2020.