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.
Mirconesian Kingfisher Todiramphus cinnamominus is being split into T. cinnamominus, T. pelewensis and T. reichenbachii, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, T. cinnamominus (BirdLife species factsheet) was listed as Least Concern on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. Although this species was estimated to have a restricted range, it was not believed to approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence of less than 20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appeared to be decreasing, the decline was not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (at least a 30% decline over ten years or three generations). The population size has not been quantified, but it was not believed to approach the thresholds for Vulnerable under the population size criterion (fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).
T. cinnamominus (as defined following the taxonomic change) is known only from Guam (Fry and Fry 1999, del Hoyo et al. 2001). It is thought to warrant listing as Extinct In The Wild, as what are thought to have been the last 29 birds in the wild were captured for captive breeding in 1986 (del Hoyo et al. 2001, Szabo et al. 2012). The primary driver of its decline was predation by brown tree-snake Boiga irregularis (Fritts and Rodda 1998).
T. reichenbachii is endemic to Pohnpei Island, where it occupies forest and woodland areas, as well as modified and edge habitats (Fry and Fry 1999, del Hoyo et al. 2001). It may qualify as Vulnerable under criterion D2, on the basis that it occurs on one small island, where it appears to be increasing or stable, but is susceptible to the potential introduction of brown tree-snake, which is expected to be catastrophic and would probably result in the species qualifying as Critically Endangered or Extinct within one to two generations.
T. pelewensis is endemic to the islands of the Palau archipelago (Fry and Fry 1999, del Hoyo et al. 2001) and is likely to warrant listing as Least Concern on the basis that it is not thought to meet the thresholds for Vulnerable under any of the IUCN criteria. The species is characterised as quite common (Fry and Fry 1999, del Hoyo et al. 2001), with apparently no evidence of declines. It is unclear whether there are any plausible threats that could drive the species to qualify as threatened within one or two generations. The accidental introduction of alien predators such as brown tree-snake remains a potential threat, but the species’s wide distribution in the archipelago would appear to limit the likely impacts of such an event.
Comments on these suggested categories are invited and further information would be welcomed.
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.
Fritts, T. H. and Rodda, G. H. (1998) The role of introduced species in the degradation of island ecosystems: A Case History of Guam. Annual Review of Ecology and Systematics 29: 113–140.
Szabo, J. K., Khwaja, N., Garnett, S. T. and Butchart, S. H. M. (2012) Global Patterns and Drivers of Avian Extinctions at the Species and Subspecies Level. PLoS ONE 7(10): e47080. doi:10.1371/journal.pone.0047080
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.