Justification This species is listed as Endangered because it has a very small, declining population, and range on one island. Declines are expected to continue as habitat degradation continues owing to heavy sheep-grazing and other factors.

Family/Sub-family Psittacidae

Species name author (Lawrence, 1871)

Taxonomic source(s) Stotz et al. (1996)

Taxonomic note Aratinga holochlora (Sibley and Monroe 1990, 1993) was previously split into A. holochlora, A. brevipes, A. rubritorquis and A. strenua following Stotz et al. (1996), contra AOU (1998). Following a review by the BirdLife Taxonomic Working Group (BTWG), A. brevipes and A. rubritorquis are retained as species contra AOU (1998), but A. strenua has been lumped with A. holochlora contra AOU (1998). The BTWG recognises A. rubritorquis and A. brevipes as species separate from A. holochlora for the reasons given in Howell and Webb (1995); (for brevipes see also Collar 1997 and Juniper and Parr 1998). For rubritorquis and holochlora, the assortative behaviour reported in a mixed roost, largely parapatric distributions, and the (albeit relatively minor) morphological differences are considered sufficient to warrant their separation, pending further study. For brevipes and holochlora, the BTWG acknowledges that the morphological differences are relatively minor but finds the report that their voices are "notably different" (Howell and Webb 1995) more persuasive, and separates them pending a rigorous vocal review and analysis. The taxon strenua is treated as a subspecies of A. holochlora following Forshaw (1989), who found that the two forms intergrade in all measurements and concluded that "strenua is nothing more than a poorly differentiated race", a view supported by Juniper and Parr (1998).

Identification 31-33 cm. Plain green parakeet. Orbital skin tinged brown. Similar spp. Only parakeet on the island. Voice High-pitched, screeching krree krree. Also chirping and short kee kee kee screams.

Population estimate

Population trend

Range estimate (breeding/resident)

Country endemic?

300

decreasing

150 km²

Yes

Range & population Aratinga brevipes is endemic to Socorro in the Revillagigedo Islands, Mexico. The population was estimated at 400-500 birds within c.35 km² of suitable habitat in 1991. Numbers were considered stable and did not decline subsequently in the early 1990s^1,2. However, there may have been some contraction in range since c.1960. Surveys from 2006 and 2007 estimated a population of c.300 individuals, suggesting a population decline from previous population estimates⁹.

Ecology: It inhabits forests of Bumelia socorrensis, Psidium socorrensis, Guettarda insularis, Ilex socorrensis and Ficus cotinifolia at elevations of 350 m-850 m. It nests exclusively in natural cavities within B. socorroensis trees¹, and the seeds and fruit pulp of this species comprise over 50% of the diet. The breeding season begins in November, and nests are attended by at least three individuals. After the breeding season, birds tend to form flocks of 7-40 individuals, with larger groups of 50-100 gathering in undisturbed forests on the northern slopes of the island.

Threats The spread of erosion and, in places, the lack of forest regeneration caused by heavy sheep-grazing has presumably had a deleterious effect on the extent of suitable habitat. There may be some predation by feral cats, but the species is relatively tame and its remains have not been found in cat scats. Outbreaks of a permanent locust Schistocerca piceifrons swarm have occurred twice a year since 1994, resulting in damage to the leaves, flowers and fruit of indigenous forests, with at least 30 ha lost to defoliation so far⁷. Outbreaks may be favoured by the habitat degradation caused by introduced species⁹. The presence of an active naval base on the island and the lack of prevention measures means that the risk of rat introduction is high⁸.

Conservation measures underway CITES Appendix II. The Revillagigedo Islands were declared a biosphere reserve in 1994⁴. A captive-breeding programme has been instigated for potential reintroduction³. The Mexican Navy has reduced the sheep population to c.300⁷. Sheep eradication is planned for 2008-2009⁸. Some control of feral cats has been undertaken⁵, and there are plans to eradicate cats in 2009, at the earliest⁸. Reports that rats have recently colonised Socorro have proved to be unfounded⁶. A pilot programme of nest-box provision is to be initiated⁷.

Conservation measures proposed Monitor the population through regular surveys. Eradicate sheep and cats from Socorro⁸. Eradicate rabbits from adjacent Clarion Island to prevent their transportation and introduction to Socorro⁸. Implement and maintain an effective invasive animal and plant introduction prevention programme with a focus on preventing rat introduction⁸. Control, but do not eliminate, the locust swarm⁹.

References Collar et al. (1992). 1. Rodríguez-Estrella (1995). 2. Rodríguez-Estrella et al. (1996). 3. R. Rodríguez-Estrella in litt. (1999). 4. Stattersfield et al. (1998). 5. B. Tershy in litt. (1998, 1999). 6. J. E. Martínez-Gómez in litt. (1999, 2000). 7. J. E. Martínez-Gómez in litt. (2007). 8. B. Tershy in litt. (2007). 9. Song et al. (2006).

Further web sources of information

Alliance for Zero Extinction (AZE) species/site profile. This species has been identified as an AZE trigger due to its IUCN Red List status and limited range.

Text account compilers Phil Benstead (BirdLife International), Stuart Butchart (BirdLife International), David Capper (BirdLife International), Isabel Isherwood (BirdLife International), Joe Taylor (BirdLife International)

Contributors Juan Esteban Martínez-Gómez (Island Endemics Foundation/Endémicos Insulares), Ricardo Rodríguez-Estrella, Bernie Tershy (Island Conservation)

IUCN Red List evaluators Stuart Butchart (BirdLife International), Joe Taylor (BirdLife International)

Recommended citation BirdLife International (2009) Species factsheet: Aratinga brevipes. Downloaded from http://www.birdlife.org on 9/2/2010

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.

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