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.
Silktail Lamprolia victoriae is being split into L. victoriae and L. klinesmithi, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, Lamprolia victoriae was listed as Near Threatened under criteria B1ab(iii,v);C1, on the basis that it had a moderately small population in a small range, which was declining as a result of habitat loss. L. victoriae (as now defined following the taxonomic change) is found in forest and plantations near forest on the island of Taveuni in Fiji (Gregory and Bonan 2016), with an Extent of Occurrence of 518 km2. While this species’s habitat continues to be degraded (Gregory and Bonan 2016) it does not appear to be severely fragmented or restricted to a limited number of locations* on the island, and so may not qualify for a threatened category due to range. In 2000 the population was estimated at 10,000-16,000 mature individuals (G. Dutson in litt. 2005). Therefore, the species does not quite qualify for a threatened category due to population size criterion C, although we would welcome more recent population estimates. Therefore, with the current information we recommend this species be listed as Near Threatened under criteria B1ab(iii,v);C2a(ii).
L. klinesmithi is found in areas of forest, logged forest and plantations near to forest in the Natewa Peninsula of Vanua Levu, Fiji (Gregory and Bonan 2016), with an Extent of Occurrence of only 263 km2. Logging and forest degradation continue to threaten its habitat Gregory and Bonan 2016) as does planting of mahogany, although this has slowed recently (Gregory and Bonan 2016). The population has been estimated at 6,000-12,000 mature individuals (J. S. Kretzschmarin litt.2000), although more recent estimates would be welcomed. As such this species may qualify as Vulnerable under criterion C2a(ii). If there is any evidence to suggest that the population may be severely fragmented or restricted to a limited number of locations* then it may warrant listing as Vulnerable or Endangered under criterion B1ab(i,ii,iii,v).
Comments are invited on these proposed categories and further information would be welcomed.
*Note that the term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat (IUCN 2001, 2012).
Gregory, P. & Bonan, A. (2016). Silktail (Lamprolia victoriae). 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/59268 on 9 September 2016).
IUCN. 2001. IUCN Red List Categories and Criteria: Version 3.1. Gland, Switzerland and Cambridge, UK: IUCN Species Survival Commission.
IUCN. 2012. Guidelines for Application of IUCN Red List Criteria at Regional and National Levels: Version 4.0. Gland, Switzerland and Cambridge, UK: IUCN.
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.