Archived 2016 topics: Yellow-shouldered Amazon (Amazona barbadensis): Downlist to Near Threatened?

Amazona barbadensis (BirdLife species factsheet) is found in several isolated populations in northern coastal Venezuela and the islands of Margarita, La Blanquilla, Curaçao and Bonaire (to Netherlands) (Rodríguez-Ferraro 2009).  It is currently extinct in the Paraguaná peninsula on mainland Venezuela (Briceño-Linares et. al. 2011).  It is now extinct on Aruba (to Netherlands).

It is currently classified as Vulnerable under Criterion B1b because it has a restricted range within which trade and habitat loss and possibly introduced mammalian predators have been likely to be causing declines (Collar et al. 1992).

The species’s island populations appear to fluctuate, but total over 2,300 individuals (J. P. Rodriguez in litt. 2016) (over 1,600 on Margarita in 2008 [Briceño-Linares et al. 2011] around 100 on Blanquilla in 1996-1998 [Rodríguez-Ferraro and Sanz 2007] and over 650-800 on Bonaire in 2012 [Department of Resources and Planning, Bonaire per R. Martin and S. Williams in litt. 2012]).  The mainland population has not been estimated but seems low and probably numbers in the hundreds (J. P. Rodriguez in litt. 2016).  Its population is therefore likely to number at least 2,500 individuals, equating to 1,667 mature individuals, and is placed in the band 1,500-7,000 mature individuals.

The species is suspected to have previously undergone a slow population decline owing to illegal poaching and habitat loss. As a result of extensive conservation efforts including round-the-clock guarding of nests from poachers, the largest subpopulation, on Margarita, has increased from 750 birds in 1989 (Sanz and Grajal 1998) to over 1,600 in 2008 (Briceño-Linares et al. 2011). The population on Bonaire was estimated to number 400 individuals in 2006 (Williams and Martin 2006) and 600-850 individuals in 2012 (Department of Resources and Planning, Bonaire per R. Martin and S. Williams in litt. 2012).  The mainland population was in decline in 2003 (Hilty 2003) but the current trend is unknown and we are unable to determine the overall population trend for this species.

This species’s Extent of Occurrence (EOO) has recently been revised as 135,000km2, based on a Minimum Convex Polygon (the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence) (IUCN 2001, 2012).  This updated EOO figure no longer falls under the Threshold of 20,000 km2, under which a species may be listed as Vulnerable under Criterion B1.

The species’s estimated population size of 1,500-7,000 mature individuals falls below the minimum threshold to be listed as Vulnerable (and possibly below the minimum threshold to be listed as Endangered) under Criterion C2.  However, the species is not known to be undergoing a continuing decline and it does not meet the subcriteria to be listed as Vulnerable under this criterion since the largest subpopulation numbers more than 1,000 individuals (1,600 individuals on Margarita, roughly equating to 1,067 mature individuals, rounded to 1,100 mature individuals) and no single subpopulation holds more than 90% of the total population.  Should there be evidence that this species’s population is continuing to decline, it may be appropriate to list the species as Near Threatened under Criterion C2a(i).  If the population is not continuing to decline, it may be appropriate to list the species as Near Threatened because it is dependent on conservation, the cessation of which would result in the taxon qualifying for one of the threatened categories under Criterion C2 within a period of five years.

Additional information, particularly on the species’s current population trends on mainland Venezuela, and comments on this proposal are welcomed.

 

References

Briceño-Linares, J.M.; Rodríguez, J.P.; Rodríguez-Clark, K.M.; Rojas-Suárez, F.; Millán, P.A.; Vittori, E.G.; Carrasco-Muñoz, M. 2011. Adapting to changing poaching intensity of yellow-shouldered parrot (Amazona barbadensis) nestlings in Margarita Island, Venezuela. Biological Conservation 144: 1188–1193.

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.

IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. IUCN Species Survival Commission. IUCN, Gland, Switzerland and Cambridge, U.K.

IUCN. 2012. IUCN Red List Categories and Criteria: Version 3.1. Second edition. Gland, Switzerland and Cambridge, UK: IUCN. Available at www.iucnredlist.org/technical-documents/categoriesand-criteria

Rodríguez-Ferraro, A. 2009. Who’s who? & how we know – genetics & conservation. PsittaScene 21(3): 3-5.

Rodríguez-Ferraro, A.; Sanz, V. 2007. Natural history and population status of the Yellow-shouldered Parrot on La Blanquilla Island, Venezuela. Wilson Journal of Ornithology 119(4): 602-609.

Sanz, V.; Grajal, A. 1998. Successful reintroduction of captive-raised Yellow-shouldered Amazon parrots on Margarita Island, Venezuela. Conservation Biology 12: 430-441.

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3 Responses to Archived 2016 topics: Yellow-shouldered Amazon (Amazona barbadensis): Downlist to Near Threatened?

  1. Virginia Sanz D'Angelo says:

    Thank you for giving the opportunity to send information on the species. Here are my comments to specific topics expresed above.

    Birdlife: “The species is suspected to have previously undergone a slow population decline owing to illegal poaching and habitat loss. As a result of extensive conservation efforts including round-the-clock guarding of nests from poachers, the largest subpopulation, on Margarita, has increased from 750 birds in 1989 (Sanz and Grajal 1998) to over 1,600 in 2008 (Briceño-Linares et al. 2011). The population on Bonaire was estimated to number 400 individuals in 2006 (Williams and Martin 2006) and 600-850 individuals in 2012 (Department of Resources and Planning, Bonaire per R. Martin and S. Williams in litt. 2012). The mainland population was in decline in 2003 (Hilty 2003) but the current trend is unknown and we are unable to determine the overall population trend for this species.”

    • Comment: The population in Margarita Island is stable, but the numbers only are maintained because the permanent conservation project that keeps running in one of the main breeding areas (La Chica creek), with a strong component of nest surveillance (day and night). Otherwise, the population will decrease again because the poaching pressure is still high. Jessica Ortega did an evaluation of Western mainland populations in the year 2012, and she estimated the population size in 5000 individuals. The species is threatened by poaching, goats and small scale farming. In Piritu (Eastern part of the distribution) the population is affected by the arids extraction , and urban and industrial development that are reducing the available habitat. There is no evaluation of this population. In Araya, another locality in the East part of the country, local dwellers inform that the population is reducing and there is also a high poaching pressure and changes in land use to agriculture.

    Birdlife: “This species’s Extent of Occurrence (EOO) has recently been revised as 135,000km2, based on a Minimum Convex Polygon (the smallest polygon in which no internal angle exceeds 180 degrees and which contains all the sites of occurrence) (IUCN 2001, 2012). This updated EOO figure no longer falls under the Threshold of 20,000 km2, under which a species may be listed as Vulnerable under Criterion B1.”

    • Comment: I would like to know based on what data this polygon was done. The species has reduced its historical area of distribution, and the decrease keeps nowadays. A PhD student I am supervising, is working with changes in the distribution of eight Venezuelan psittacids, including A. barbadensis. She is using models and museum data for historic distribution and inventories and birdwatchers observation for current distribution. The preliminary data show a reduction in the distribution between 1984 and 2004 of about 45% from 90.000 km2 in 1984 to 50.000 in 2004. A previous paper, on Amazona species, shows the same trend for A. barbadensis too (Ferrer, J.R., Sánchez, A. Rodríguez-Clark, K.M., Rodríguez, J.P., Rodríguez, G.A. 2014. Using limited data to detect changes in species distributions: Insights from Amazona parrots in Venezuela. Biological Conservation, 173: 133-143)
    • Also is important to consider that the species has a fragmented distribution, even in the more extensive areas in Falcon and Lara states, so the MC polygon is not an adequate method to represent the species’ distribution.

    Birdlife: “The species’s estimated population size of 1,500-7,000 mature individuals falls below the minimum threshold to be listed as Vulnerable (and possibly below the minimum threshold to be listed as Endangered) under Criterion C2. However, the species is not known to be undergoing a continuing decline and it does not meet the subcriteria to be listed as Vulnerable under this criterion since the largest subpopulation numbers more than 1,000 individuals (1,600 individuals on Margarita, roughly equating to 1,067 mature individuals, rounded to 1,100 mature individuals) and no single subpopulation holds more than 90% of the total population. Should there be evidence that this species’s population is continuing to decline, it may be appropriate to list the species as Near Threatened under Criterion C2a(i). If the population is not continuing to decline, it may be appropriate to list the species as Near Threatened because it is dependent on conservation, the cessation of which would result in the taxon qualifying for one of the threatened categories under Criterion C2 within a period of five years.”

    • Comment: We do not have quantitative data of the historical population size for the whole range of distribution. However, based on the information we current have, we can affirm that he species must be decreasing in Venezuela because the threats have not stopped in any part of the distribution, except in Margarita Island (the situation was already explained above, conservation dependent). La Blanquilla has not been evaluated recently, but neither the poaching pressure nor the predation by cats have been controlled since the last census in 1998. The impact is strong in an island of only 65 km2. Only in year 2012 we had the first quantification of the most important populations in the western mainland, so we do not have previous reliable data to compare with. But, based on the confiscations done in the 90’s, the current poaching pressures, and the reduction of the geographic distribution registered, is reasonable to say that the population trend is clearly decreasing.
    • With the critic economic situation Venezuela is suffering in the last years, what we have seen, over the country, is an increase on natural resources pressure, with higher levels of hunting, poaching and the reduction of environmental guard.
    • This year we had a very strong drought affecting the country from January to July. In Margarita, in May, the parrots moved to towns to look for food because there were neither fruits nor seeds for feeding in the natural habitat. Another example, Forpus passerinus breeding in the Llanos, delayed the beginning of nesting and there were few nests. We do not know the effect in other parts of the distribution, but should have been similar. The distribution of the species in arid lands makes it more vulnerable to changes in the patterns of rainfall, something that will be increasingly common under the scenarios of climatic change. Arid ecosystems in Venezuela are one of the most endangered following the “Red Book of Terrestrial Ecosystems” (Rodríguez et al 2010)
    • The species only could be able to recover or keeps the numbers under the umbrella of permanent conservation projects. To download the species to “Near Threatened” will not represent the real situation and would only make even more difficult to get the financial resources to keep the project in Margarita running and will reduce the possibility to start a new one in Falcon State or other localities.
    • The proposal is to keep the species as Vulnerable, based on criteria:
    • A2c
    • A2d
    • A2e (for La Blanquilla population)
    • C1

  2. Hannah Wheatley (BirdLife) says:

    Based on further review of additional information, our preliminary proposal for the 2016 Red List would be to list this species as Vulnerable under criterion E.

    There is now a period for further comments until the final deadline of 28 October, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Hannah Wheatley (BirdLife) says:

    Recommended categorisation to be put forward to IUCN

    Following further review, the recommended categorisation for this species was changed.

    This species is now recommended to be listed as Vulnerable under criterion B1ab(i,ii,iii). This species has a small range within which trade and habitat loss and possibly introduced mammalian predators have caused declines. It is currently listed as Vulnerable on this basis, but may warrant reassessment in the near future if declines are found to have ceased and on the basis of revised calculation of the Extent of Occurrence.

    Final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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