Archived 2016 topics: Yellow-eyed Junco (Junco phaeonotus) is being split: request for information on J. bairdi

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 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 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.

Yellow-eyed Junco Junco phaeonotus is being split into J. phaeonotus and J. bairdi, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, J. phaeonotus (http://www.birdlife.org/datazone/species/factsheet/22721107) was listed as Least Concern, on the basis that it did not approach the threshold for any criteria for listing as Vulnerable. J. phaeonotus (as defined now following the taxonomic change) remains widespread across large areas of Mexico, into west Guatemala and New Mexico and Arizona, USA. It is common in suitable areas in its range (Rising 2016), in montane conifer and pine-oak forest (Rising 2016). It may be undergoing a decline (Butcher and Niven 2007) but it does not approach the threshold for Vulnerable. Therefore, it is proposed that this species be listed as Least Concern.

J. bairdi is found only in a very limited range in semi-arid woodland at the tip of the Baja California peninsula, Mexico (Rising 2016). The pre-split species was described as common to abundant (Rising 2016), but assuming that not all of the species’s range is occupied and using density estimates for congeners the population size may fall within the range of 2,500-9,999 mature individuals. It is unsure whether the trend for J. phaeonotus prior to the split is representative for such a small part of the formerly identified range, and so we request any further information, and if there is evidence to suggest that the population of J. bairdi is declining it may warrant listing as Vulnerable under criterion C2a(ii).

References:

Butcher, G. S. and Niven, D. K. (2007) Combining data from the Christmas bird count and the breeding bird survey to determine the continental status and trends of North American birds. National Audubon Society.

Rising, J. 2016. Yellow-eyed Junco (Junco phaeonotus). In: del Hoyo, J., Elliott, A., Sargatal, J., Christie, D.A. & de Juana, E. (eds.). Handbook of the Birds of the World Alive. Lynx Edicions, Barcelona. (retrieved from http://www.hbw.com/node/61908 on 6 October 2016).

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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One Response to Archived 2016 topics: Yellow-eyed Junco (Junco phaeonotus) is being split: request for information on J. bairdi

  1. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 Red List would be to list:

    J. phaeonotus as Least Concern.

    J. bairdi conservatively as NT under criterion C2a(ii).

    There is now a period for further comments until the final deadline of 28 October, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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