Rufous Hornbill (Buceros hydrocorax) is being split: list both B. hydrocorax and B. mindanensis as Vulnerable?

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 2013 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.

Rufous Hornbill Buceros hydrocorax is being split into B. hydrocorax and B. mindanensis, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, B. hydrocorax (BirdLife species factsheet) was listed as Near Threatened under criteria A2cd+3cd+4cd, on the basis that it was suspected to be undergoing a moderately rapid population decline (approaching 30% over three generations [c.55 years]) owing to on-going habitat loss and persecution.

B. hydrocorax (as defined following this taxonomic change) is found on Luzon and Marinduque, whilst B. mindanensis (incorporating semigaleatus) is found on Balut, Basilan, Biliran, Bohol, Buad, Bucas Calicoan, Dinagat, Leyte, Mindanao, Panaon, Samar, Siargao and Talicud (Kennedy et al. 2000, del Hoyo et al. 2001). They occur largely in primary forest, but may also be found in mature secondary forest and selectively logged forest.

It is suggested that both species be listed as Vulnerable under criteria A2cd+3cd+4cd, on the basis that they are suspected to be undergoing rapid population declines (30-49% over three generations [c.55 years]), owing to the on-going threats stated above.

Comments on these suggested categories are invited and further information would be welcomed.

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (2001) Handbook of the birds of the world, Vol 6: Mousebirds to Hornbills. Barcelona, Spain: Lynx Edicions.

Kennedy, R. S., Gonzales, P. C., Dickinson, E. C., Miranda, H. C., Jr. and Fisher, T. H. (2000) A guide to the birds of the Philippines. Oxford: Oxford University Press.

Tobias, J. A., Seddon, N., Spottiswoode, C. N., Pilgrim, J. D., Fishpool, L. D. C. and Collar, N. J. (2010) Quantitative criteria for species delimitation. Ibis 152: 724–746.

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