This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for passerines
Lynx Edicions and BirdLife International will soon publish the second volume of theHBW-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 2 of the checklist (for passerines) will begin to be incorporated into the 2016 Red List update, with the remainder 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.
Tomtit Petroica macrocephala is being split into P. macrocephala and P. dannefaerdi following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, P. macrocephala (http://www.birdlife.org/datazone/species/factsheet/22704812) was listed as Least Concern. The species has a large range and is not believed to approach any of the thresholds for Vulnerable status: although the population trend appears to be decreasing, the decline is not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). It is therefore proposed that this species remains as Least Concern.
P. dannefaerdi (as now defined following the taxonomic change) is found only on the Snares Islands with a total Area of Occupancy of c.3.5 km2. The population has been estimated at around 500 pairs (McLean and Miskelly 1988), and densities appear to have remained fairly stable since the late 1940s (Miskelly et al. 2001). However, given the low population numbers (c.1,000 mature individuals) and restricted area of occupancy and number of locations, it is suggested that this newly split species should be listed as Vulnerable under criteria D1 and D2.
Comments are invited on these proposed categories and further information would be welcomed.
McLean, I.G.; Miskelly, C.M. 1988. Breeding biology of the black tit (Petroica macrocephala dannefaerdi) on the Snares Islands, New Zealand. New Zealand natural sciences 15: 51-59.
Miskelly, C.M.; Sagar, EM.; Tennyson, A.J.D; Scofield, R.P. 2001. Birds of the Snares Islands, New Zealand. Notornis 48(1): 1-40.
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: