The initial deadline for comments on this topic is 28 April 2014, and therefore later than for most other topics currently under discussion.
This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines
Lynx Edicions and BirdLife International will soon publish the HBW-BirdLife Illustrated Checklist of the Birds of the World, building off the Handbook of the Birds of the World series, and BirdLife’s annually updated taxonomic checklist.
The new Checklist will be based on the application of criteria for recognising species limits described by Tobias et al. (2010). Full details of the specific scores and the basis of these for each new taxonomic revision will be provided in the Checklist.
Following publication, an open and transparent mechanism will be established to allow people to comment on the taxonomic revisions or suggest new ones, and provide new information of relevance in order to inform regular updates. We are also actively seeking input via a discussion topic here regarding some potential taxonomic revisions that currently lack sufficient information.
The new Checklist will form the taxonomic basis of BirdLife’s assessments of the status of the world’s birds for the IUCN Red List. The taxonomic changes that will appear in volume 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), to be incorporated into subsequent Red List updates.
Preliminary Red List assessments have been carried out for the newly split or lumped taxa. We are now requesting comments and feedback on these preliminary assessments.
Horned Curassow Pauxi unicornis is being split into P. unicornis and P. koepckeae, following the application of criteria set out by Tobias et al. (2010).
Prior to the taxonomic change, P. unicornis (BirdLife species factsheet) was listed as Endangered under criteria A2bcd+3bcd+4bcd, on the basis that the species was suspected to be undergoing a population decline of 50-79% over 44 years (estimate of three generations), owing to habitat loss and hunting pressure. Although the factsheet gives the rate of decline as ≥ 30% over 44 years, based on a forest loss analysis, the impact of hunting pressure is thought to be driving a much more rapid decline. The pre-split species is regarded as poorly known and the total population was estimated to number 1,000-4,999 mature individuals, assumed to roughly equate to 1,500-7,500 individuals in total.
Hunting for food seems to be the most serious threat in both Bolivia and Peru, with substantial negative impacts suspected throughout the range of the pre-split species (Gastañaga 2006). In Bolivia, forests within its elevation range are being cleared for cultivation (Dinerstein et al. 1995, Fjeldså in litt. 1999, Maillard 2006). Road-building and associated development have a negative impact and inhibit dispersal (Herzog and Kessler 1998, Fjeldså in litt. 1999). In Peru, subsistence agriculture threatens its habitat (R. MacLeod in litt. 2000), as does the opening up of the foothills to colonisation and hunting. Mining, oil exploration and illegal logging are potential future threats in El Sira, as well as forest clearance by colonists.
P. koepckeae is known only from the Cerros del Sira in Huánuco, Peru, and went unrecorded since its description in 1969 until local knowledge surveys in 2003 and observations in 2005 confirmed its continued existence (Gastañaga 2006, Gastañaga et al. 2011). The total population is estimated to number fewer than 400 individuals (Gastañaga in litt. 2007), with evidence that its numbers are declining (Gastañaga and Hennessey 2005). The species occurs at densities of up to 20 individuals/km2, although this appears to be exceptional and at most sites only one or two individuals have been found (R. MacLeod in litt. 2007).
This species inhabits cloud forest in the Cerros del Sira, being recorded elevations of around 1,100-1,700 m (Gastañaga et al. 2011, Socolar et al. 2013), although in the dry season individuals have also occasionally been found at lower levels (down to 950 m) along the upper edge of adjacent montane forest.
It is suggested that this species qualifies as Critically Endangered under criterion C2a(ii), on the basis that it is likely to number fewer than 250 mature individuals, forming a single sub-population, which is in continuing decline owing to on-going hunting pressure, habitat loss and habitat degradation.
P. unicornis (as defined following the taxonomic change) is found in Bolivia, being known from the adjacent Amboró and Carrasco National Parks (Cox et al. 1997, Herzog and Kessler 1998, Mee 1999, R. MacLeod in litt. 2000), and more recently has been found in Isiboro-Secure Indigenous Territory and National Park (TIPNIS) and along the outer edge of the Cordillera Mosetenes, Cochabamba, Bolivia (R. MacLeod in litt. 2007). It was formerly found along the length of Carrasco’s northern boundary (R. MacLeod in litt. 2000), but recent surveys found it in very few locations here (R. MacLeod in litt. 2007). Extensive searches over several years have failed to locate the species in Madidi National Park, La Paz, Bolivia (R. MacLeod in litt. 2003, Hennessey 2004, A. Maccormack in litt. 2004), in the rio Tambopata area near the Peru/Bolivia border (R. MacLeod in litt. 2004, Gastañaga and Hennessey 2005) and in the Cordillera Cocapata and along the inner edge of Cordillera Mosetenes in Cochabamba (R. MacLeod in litt. 2003, 2007).
This species inhabits dense, humid, lower montane forest and adjacent lowland evergreen forest at 400-1,400 m (R. MacLeod in litt. 2000, Gastañaga 2006, Maillard 2006, Gastañaga et al. 2011). For much of the year it stays above 550 m, but descends in the dry season (Renjifo and Renjifo 1997).
A model of forest loss in the Amazon basin since 2002 (Soares-Filho et al. 2006), combined with the species’s approximate range and data on its ecology and life history (following the methods of Bird et al. 2011), suggests that the species will lose 20-30% of suitable habitat in the Amazonian portion of its range (as defined by the model, and which accounts for 98% of its global extent of suitable habitat) over 44 years (estimate of three generations).
By taking the pessimistic (business as usual) scenario of this model and factoring in additional declines owing to the species’s susceptibility to hunting, fragmentation and edge-effects (following Bird et al. 2011), it is projected that it will decline by 39.8% over 44 years from 2002.
This Amazonian forest loss analysis suggests that the species qualifies as Vulnerable under criterion A4; however, given the categorisation of the pre-split species as Endangered under the A criterion, the forest loss analysis may underestimate the rate of population decline in this species. In accordance with this, Gastañaga et al. (2011) suggest that the species qualifies at least as Endangered and cite the A criterion. The estimated Extent of Occurrence of 9,300 km2 suggests that this species does not qualify as Endangered under the B criterion, as also suggested by Gastañaga et al. (2011). However, the species may qualify as Endangered under criterion C2 (see Gastañaga et al. 2011), if its population is estimated to include fewer than 2,500 mature individuals, either with at least 95% of mature individuals in one sub-population, or with multiple sub-populations of no more than 250 mature individuals each. Gastañaga et al. (2011) also suggest that P. unicornis could qualify as Critically Endangered under criterion A2d (population reduction of ≥80% over the past 44 years) on the basis of an observed deterioration in the level of protection afforded by national parks and associated increases in logging, hunting and cultivation within park boundaries.
Comments are invited and further information would be welcomed.
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Cox, G., Read, J. M., Clarke, R. O. S. and Easty, V. S. (1997) Studies of Horned Curassow Pauxi unicornis in Bolivia. Bird Conservation International 7: 199–211.
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