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.
Broad-billed Hummingbird Cynanthus latirostris is being split into C. latirostris, C. doubledayi and C. lawrencei, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, C. latirostris (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.
C. lawrencei is endemic to the Islas Tres Marias, Mexico, where it probably inhabits arid and semi-arid bushy woodland and scrub (Howell and Webb 1995, del Hoyo et al. 1999). Threats to birds on the Islas Tres Marias include urban development, livestock farming, wood-cutting and introduction of non-native species (Arizmendi and Valdelamar 2000).
It is suggested that the species be listed as Near Threatened under criteria C2a(i); D1+2, on the basis that it occupies a very small range (with an Extent of Occurrence estimated at c.420km2), being present on just four small islands, and is estimated to have a very small population (perhaps fewer than 2,500 mature individuals, and likely to approach as few as 1,000 mature individuals, with fewer than 1,000 mature individuals in each subpopulation); however, there are not known to be any declines in the population or the species’s habitat. Nevertheless, it remains susceptible to human activities, the potential introduction of non-native species and stochastic events such as hurricanes, and could qualify as threatened in the near future.
C. doubledayi is found along the Pacific slope in Guerrero, Oaxaca and Chiapas in southern Mexico, occurring in arid and semi-arid wooded habitats and scrub, whilst C. latirostris (as defined following the taxonomic change, and incorporating magicus and propinquus) is found in similar habitats, as well as rocky canyons in deserts, and is a migrant breeder as far north as southern Arizona and south-western New Mexico, and is resident in much of north-western and central Mexico, to northern Veracruz and possibly north-western Guerrero (Howell and Webb 1995, del Hoyo et al. 1999).
Both C. doubledayi and C. latirostris are likely to be listed as being of Least Concern, on the basis that they are not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.
Comments on these suggested categories and further information would be welcomed.
Arizmendi, Ma. del C. and Valdelamar, L. M. (eds) (2000) Áreas de Importancia para la Conservación de las Aves en México. Mexico City, Mexico: CONABIO.
del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the birds of the world, Vol 5: Barn-owls to Hummingbirds. Barcelona, Spain: Lynx Edicions.
Howell, S. N. G. and Webb, S. (1995) A guide to the birds of Mexico and northern Central America. Oxford, UK: 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.