The BirdLife Taxonomic Working Group intends to implement the split of Palkachupa Cotinga Phibalura boliviana from P. flavirostris following Hennessey (2010), who demonstrated significant differences between the resident boliviana (restricted to a small area of western Bolivia) and the nominate flavirostris 2,500 km distant in southeast Brazil (which exhibits strong seasonal movements). This taxonomic change is currently under consideration by SACC (see http://www.museum.lsu.edu/~Remsen/SACCprop494.html).
The total population of boliviana has been estimated to number 600-800 individuals (ABC 2011), with the majority (400-500 individuals; Hennessey 2010) in an area surrounding the town of Apolo, and the population stronghold thought to lie around the small village of Atén, just outside Madidi National Park. The species has been found within an altitudinal range of 1,400-2,000 m, with breeding taking place from August to March, peaking in January. Much of its range has undergone large-scale forestation clearance and burning for cattle ranching and agriculture over the past century, which continues to this day.
The species’s Extent of Occurrence has been estimated at 651 km² (see attached map). Note that, as re-emphasised recently by IUCN, EOO is a measure of the spread of extinction risk and does not equate to the actual range size / area occupied by the species, which may be much smaller). A further area of c3,900 km² contains potentially suitable moist high altitude Cerrado habitat, however it is doubtful that the species occurs within much of this area, particularly as it may depend on three tree species which are absent from much of this area (B. Hennessey in litt. 2011) and consequently this area is not included for the purposes of the Red List assessment.
Based on an EOO of 650 km², and a population estimate of 600-800 individuals, and assuming that the species is undergoing a continuing decline owing to habitat destruction and degradation, it appears that the species should be classified as either Endangered or Vulnerable under the B and/or C criteria, depending on the subpopulation structure, degree of fragmentation and number of locations. Key questions to enable assessment of the species are:
Is the cotinga’s distribution severely fragmented?
A taxon can be considered to be severely fragmented if most (>50%) of its total area of occupancy is in habitat patches that are (1) smaller than would be required to support a viable population, and (2) separated from other habitat patches by a large distance (IUCN 2001).
Does the cotinga have multiple subpopulations, and if so, how many individuals are likely to be in the largest subpopulation?
Subpopulations are defined as geographically or otherwise distinct groups in the population between which there is little demographic or genetic exchange (typically one successful migrant individual or gamete per year or less) (IUCN 2001).
How many locations does it occur at?
“The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat.” (IUCN 2001)
Justification for the number of locations used in Red List assessments should include reference to the most serious plausible threat(s). For example, where the most serious plausible threat is habitat loss, a location is an area where a single development project can eliminate or severely reduce the population. Given this definition, would the number of locations be estimated at 1, 2-5, 6-10 or greater than 10 for the cotinga?
Information on the likely rate of population decline would also be welcomed in order to assess the species against the A criterion. The generation length has been estimated at 4.6 years (BirdLife International unpubl. data), meaning that the species’s population trend should be assessed over a period of 14 years (three generations). Suspected reductions in the total population of at least 80% in the past 14 years (three generations), or predicted to occur in the next 14 years, would mean the species was eligible for classification as Critically Endangered under A, whereas declines of 51-70% and 30-49% would warrant classification under Endangered and Vulnerable respectively.
With apologies for the very short turnaround period, please send any comments and information on this species by January 31st if possible – preliminary decisions on status changes to feed into the 2012 Red List update will be made then, with a final opportunity to comment before final decisions are made in mid February. Forum discussions on species for which we have not had sufficient input to make a decision will be held open with the aim of soliciting further feedback in time for the 2013 update.
HENNESSEY, A. B. 2011. Species rank of Phibalura (flavirostris) boliviana based on plumage, soft part color, vocalizations, and seasonal movements. Wilson J. Ornithology 123: 454-458
IUCN (2001) IUCN Red List Categories and Criteria version 3.1 http://www.iucnredlist.org/apps/redlist/static/categories_criteria_3_1