EN
Mangrove Hummingbird Amazilia boucardi



Justification

Justification of Red List Category
The species occurs in a restricted range, and its small population is under pressure from habitat loss. It consequently qualifies as Endangered.

Population justification
Censuses have found densities of up to 1 individual per km of transect, and locally higher over short distances (Jones et al. 2009). The population is thus estimated to number 2,500-9,999 individuals based on an assessment of known records, descriptions of abundance and range size. This estimate is equivalent to 1,667-6,666 mature individuals, rounded here to 1,500-7,000 mature individuals.

Trend justification
The species's population is suspected to be in slow decline, in line with the clearance and degradation of mangrove forests in its range. A remote sensing study found that forests within the species's range have been lost at a rate of 1.4% over three generations (Tracewski et al. 2016). Assuming that forest loss is continuing at the same rate and population declines are proportional to forest loss, the rate of decline is unlikely to exceed 10% over three generations.

Distribution and population

Amazilia boucardi is endemic to the Pacific coast of Costa Rica, where it occurs locally from the head of Golfo de Nicoya to Golfo Dulce. The species was recently discovered in two new mangrove forest sites on the outer Nicoya Peninsula; a female was trapped in January 2005 and two were trapped in 2006 at Estero Tamarindo (Las Baulas de Guanacaste Marine National Park), and in August 2006, a male and female were observed at Playa Venado (R. Garrigues in litt. 2007). It is patchily distributed even within the four or five large mangrove forests in this range (Harcourt and Sayer 1996), probably reflecting the presence of its preferred food-plant, the Pacific mangrove Pelliciera rhizophorae. Despite tolerating some habitat alteration where P. rhizophorae remains common, it is absent from many areas of apparently suitable habitat. The population in the Important Bird Areas of Costa Rica has been estimated at 2,150-4,150 mature individuals (J. Criado in litt. 2007).

Ecology

The species occurs mainly in stands of the Pacific mangrove Pelliciera rhizophorae. Occasionally, it is observed in adjacent, non-mangrove habitats, including secondary forest and sandbars (Weller et al. 2020). The species occupies a narrow altitudinal band close to sea level (Weller et al. 2020). Nesting has been recorded between October and February.

Threats

The construction of salinas and shrimp ponds, and selective logging for charcoal production are destroying mangrove habitats (F. G. Stiles in litt. 1999). Other threats include illegal cutting, dyke and road construction (which have affected the hydrology in a number of places), and pollution (notably around the Golfo de Nicoya port of Puntarenas). The entire Pacific coast of Costa Rica is under heavy development pressure, with potentially negative effects on mangrove forests (R. Garrigues in litt. 2007). The species could be affected by a significant rise in sea-level caused by climate change (R. Garrigues in litt. 2012).

Conservation actions

Conservation Actions Underway
CITES Appendix II. Small populations occur in Tivives Biological Reserve and Golfito Faunal Refuge. Cutting mangroves is illegal in Costa Rica, but this law is widely ignored.

Conservation Actions Proposed
Survey to determine its population size, current distribution and the quality of remaining mangroves. Monitor the clearance and degradation of mangrove forests within the species's range. Investigate the causes of its absence from patches of apparently suitable habitat. Expand Carara Biological Reserve to protect mangroves around the mouth of the río Grande de Tárcoles. Protect mangroves north of Corcovado National Park around the río Sierpe (Capper et al. 1998). Perhaps use this endemic species as part of an awareness campaign to promote the protection of mangrove forests (R. Garrigues in litt. 2007).

Identification

9.5 cm. Medium-sized, bronze-and-green hummingbird. Male pale green on crown and upperparts, with bronze tinge to rump. Bronze-green tail. Turquoise-green throat and chest. Whitish underparts mottled pale green on breast and sides. Dark bill with reddish lower mandible. Female similar with mainly white underparts and little green spotting on throat and sides. Similar spp. Snowy-bellied Hummingbird A. edward has sharp contrast between green and white underparts and much rustier tail. Female White-bellied Emerald A. candida has blacker tail and more green on chest. Voice Soft djt and rapid, descending twitter.

Acknowledgements

Text account compilers
Hermes, C.

Contributors
Benstead, P., Criado, J., Garrigues, R., Isherwood, I., Sharpe, C.J., Stiles, F.G. & Taylor, J.


Recommended citation
BirdLife International (2021) Species factsheet: Amazilia boucardi. Downloaded from http://www.birdlife.org on 15/01/2021. Recommended citation for factsheets for more than one species: BirdLife International (2021) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 15/01/2021.