This discussion was first published on Dec 1 2010 as part of the 2010-2011 Red List update.
Initial deadline for comments: 31 January 2012.
Bare-necked Umbrellabird Cephalopterus glabricollis is currently listed as Vulnerable under criteria A2c; A3c; A4c, on the basis that a population decline is suspected in both the past and future at a rate equivalent to 30-49% over 10 years.
This species’s breeding population in Costa Rican Important Bird Areas (IBAs) was assessed in 2009 and was estimated at 190-330 mature individuals (Sánchez et al. 2009), which is down from the 2007 estimate of 740-1,430 mature individuals (J. Criado et al. in litt. 2007). In contrast, the 2007 estimate for the breeding population in the IBAs of Panama was given as 1,050-4,245 mature individuals, an estimate regarded by some as too high (J. Criado et al. in litt. 2007). The latest estimate for Costa Rican IBAs suggests that the species’s total population numbers fewer than 2,500 mature individuals, which could make the species eligible for uplisting to Endangered under criteria C1 and/or C2.
Criterion C1 stipulates that for Endangered status the population must also be shown to be declining at a rate of at least 20% over five years or two generations. Given that the suspected rate of decline is currently estimated at 30-49% over 10 years, owing to deforestation for conversion to pasture and cultivation, commercial logging and road construction (Powell et al. 1995, Angehr and Jordán 1998, Angehr 2003, G. Angehr in litt. 2007), a decline of 20% over five years seems likely. The difference in the estimates for the breeding populations in Costa Rican IBAs in 2007 and 2009 would imply that the species’s population was previously overestimated, or that it is in rapid decline. Criterion C2 stipulates that in addition to at least an inferred decline of unknown rate, at least 95% of all mature individuals must be in one sub-population; however, the species is thought to have more than one sub-population.
Comments are invited on this potential category change, and information is requested on the species’s likely total population size, estimated population trend and population structure to help in the evaluation of its status. Assessment of the population trend would be aided by data on the species’s generation length.
Angehr, G. R. (2003) Directory of important bird areas in Panama. Balbao, Panama: Panama Audubon Society.
Angehr, G. R. and Jordán, O. (1998) Report on the Panama Important Bird Areas program. Ancon, Panamá: Panama Audubon Society/BirdLife International.
Powell, G. V. N., Bjork, R., Montero, S. and Aleman, U. (1995) Intratropical migration by Ara ambigua: identifying habitat heterogeneity and linkages to protect biodiversity in lowland tropical wet forest of Central America. Progress report submitted to RARE Center for Tropical Conservation, Monteverde, Costa Rica.
Sánchez, J. E., Criado, J., Sánchez, C. and Sandoval, L. (2009) Costa Rica. In Devenish, C., Díaz Fernández, D. F., Clay, R. P., Davidson, I. J. and Yépez Zabala, I. eds. Important Bird Areas Americas – Priority sites for biodiversity conservation. Quito, Ecuador: BirdLife International (BirdLife Conservation Series No. 16).