This discussion was first published as part of the 2017 Red List update. At the time a decision regarding the status of several was pended, but to enable potential reassessment of these species as part of the 2018 Red List update this post remains open and the date of posting has been updated.
BirdLife Species factsheet for Red-fronted Macaw: http://datazone.birdlife.org/species/factsheet/red-fronted-macaw-ara-rubrogenys
Red-fronted Macaw (Ara rubrogenys) is currently listed as Endangered under criterion C2a(i) on that basis that it is thought to have a very small and declining population, with each subpopulation being extremely small (BirdLife International 2017). It is endemic to Bolivia, being found in a small area on the eastern slope of the Andes. This species usually nests on steep-sided river cliffs, but a small population has been found to live in holes in palms (Rojas et al. 2012). It is likely that it originally inhabited inter-Andean dry forest, but this habitat has been degraded by centuries of human activity to thorn and cactus shrub (S. K. Herzog in litt. 2007). Encroachment by agriculture, firewood cutting and charcoal production continue to affect the habitat (S. K. Herzog in litt. 2007). The species is also under threat as it is persecuted as a crop-pest (Brace et al. 1995) as well as being caught for trade, though this has reduced as a result of legal protection (Pitter and Christiansen 1995, Juniper and Parr 1998, Herrera and Hennessey 2007, A. Rojas in litt. 2007).
The population size is currently listed as falling between 670 and 2,700 mature individuals, but recent surveys have refuted this and instead suggested a far smaller number of mature, breeding individuals. Tella et al. (2013) surveyed the whole of the distribution of the species and found 35 cliffs where the species breeds (23 out of 29 previously reported breeding cliffs and 12 new sites) as well as the population breeding in palms. No site held more than 18 breeding pairs, with the majority containing ≤4 (Tella et al. 2013), and total breeding population estimates fell between c.67-136 pairs. They also found a total of 535 non-breeding individuals in six areas, as well as 33 non-breeding pairs being found at the breeding sites (Tella et al. 2013). The IUCN definition of population size (IUCN 2012) does not allow effective population size to be used to equate to mature individuals, since it may also be appropriate to count some or all reproductively suppressed individuals in the total of mature individuals. Without knowing more about the reasons for such a high proportion of non-breeding individuals in this case, it is very difficult to determine how many (if any) of these should be included within a total estimate for mature individuals. Taking the most precautionary approach, including only the currently-breeding individuals would result in a population estimate of approximately 134-272 mature individuals, which lies either side of the threshold population size for Critically Endangered under criterion C2.
Deciding whether the species qualifies as C2a(i) or C2a(ii) requires some assessment of population structure. If each breeding site were to represent a separate subpopulation then no subpopulation would contain >50 mature individuals and the species may qualify as Critically Endangered under criterion C2a(i). However, breeding areas are separated by only 10-60km, which may mean that individuals are capable of moving between sites and hence the global population may constitute only one subpopulation (see Tella et al. 2013). In this case, the species may qualify as Critically Endangered under criterion C2a(ii). Individuals with a slightly different breeding strategy – nesting in palms rather than on cliffs – may represent a separate subpopulation, but the number of pairs identified to be breeding in palms is <10% of the breeding population. Therefore, even if it were the case that there was little genetic exchange between these individuals and those that nest on cliffs, then still >90% of the population would be in one subpopulation and the species may still qualify as Critically Endangered under criterion C2a(ii).
Given the relative proximity of breeding areas to one another it is suggested that the species be considered one subpopulation and it is proposed that the species be uplisted to Critically Endangered under criterion C2a(ii). We do, however, welcome any further comments or additional information, particularly regarding population structure, and population size estimates as the new estimates do fall around the threshold values for Critically Endangered and so the possibility of the presence of other, as yet unfound, breeding areas could mean that the species should instead remain listed as Endangered.
BirdLife International (2017) Species factsheet: Ara rubrogenys. Downloaded from http://www.birdlife.org on 04/01/2017.
Brace, R. C.; Hesse, A. J.; White, A. G. 1995. The endemic macaws of Bolivia. Cotinga: 27-30.
Herrera, M.; Hennessey, A. B. 2007. Quantifying the illegal parrot trade in Santa Cruz de la Sierra, Bolivia, with emphasis on threatened species. Bird Conservation International 17: 295-300.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
Juniper, T.; Parr, M. 1998. Parrots: a guide to the parrots of the world. Pica Press, Robertsbridge, UK.
Pitter, E.; Christiansen, M. B. 1995. Ecology, status and conservation of the Red-fronted Macaw Ara rubrogenys. Bird Conservation International 5: 61-78.
Rojas, A.; Yucra, E.; Vera, I.; Requejo; A.; Tella, J. L. 2012. A new population of the globally Endangered Red-fronted Macaw Ara rubrogenys unusually breeding in palms. . Bird Conservaton International 24(3): 389-392.
Tella, J. L.; Rojas, A.; Carrete, M.; Hiraldo, F. 2013. Simple assessments of age and spatial population structure can aid conservation of poorly known species. Biol. Conserv. 167: 425-434.