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.
Blue-winged Leafbird Chloropsis cochinchinensis is being split into C. moluccensis and C. cochinchinensis, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, C. cochinchinensis (BirdLife species factsheet) was listed as Least Concern, on the basis that it was not believed to approach any of the thresholds for listing as Vulnerable under any criteria). The pre-split species was characterised as relatively common throughout a very large range, although scarce in Singapore and rather rare in Java.
C. cochinchinensis (as defined following the taxonomic change) is restricted to the island of Java, Indonesia, while C. moluccensis is found from E Bangladesh, NE India, Myanmar, southern China, Laos, Vietnam, Cambodia and Thailand, through Peninsular Malaysia, Singapore and Sumatra, and throughout Borneo (except the far north). It is considered the commonest leafbird species of humid edge and secondary growth, occurring from lowlands into, at least partly, montane forest (Wells 2016).
On Java, it has been considered rare for some time (Wells 2016), although has been observed at widely spaced locations across Java within the past 5 years (data from eBird 2016). However it was not recorded during a survey of higher altitude habitats on three volcanos on Java carried out in 2013 (Mittermeier et al. 2013), suggesting that the species may be rare at higher altitudes. Notably, throughout much of Java natural forest disappears abruptly below the boundary of protected areas, potentially implying the species has a limited area of suitable habitat now available, despite the general consideration that the pre-split species tolerates disturbance. Potentially the overall population may not be especially large, though given the size of the range it is still estimated to exceed 20,000 individuals.
As noted under the topics for Greater Green Leafbird C. sonnerati (forum) and Sumatran Leafbird C. media (forum), leafbirds have become highly fashionable in the cage bird trade (Eaton et al. 2015). This species has been recorded frequently being offered for sale in the markets in Jakarta (Chng et al. 2015) and is the most accessible species for trapping on Java: but it is presently not being traded in anything close to the numbers of Greater Green Leafbird (Eaton in litt. 2016).
Given that the species, although widespread, appears generally to occur at low density and is currently being traded, the population of Javan Leafbird C. cochinchinensis is suggested to be listed as Near Threatened, as the population is suspected to be undergoing a moderately rapid decline, which may approach the thresholds for listing the species as Vulnerable under A2d + A3d + A4d. If the impact of trapping for the cage bird trade is not thought sufficient to cause population level impacts in the order of a 20-30% decline, then the species should be listed as Least Concern.
Comments are invited on these proposed categories and further information would be welcomed.
Chng, S. C. L., Eaton, J. A., Krishnasamy, K., Shepherd, C. R. & Nijman, V. 2015. In the market for extinction: an inventory of Jakarta’s bird markets. Petaling Jaya, Selangor, Malaysia: TRAFFIC.
eBird. 2016. eBird: An online database of bird distribution and abundance [web application]. eBird, Ithaca, New York. Available: http://www.ebird.org. (Accessed: Date October 12th 2016).
Mittermeier, J. C., Oliveros, C. H., Haryoko, T., Irham, M. and Moyle, R. G. 2014. An avifaunal survey of three Javan volcanoes—Gn Salak, Gn Slamet and the Ijen highlands. BirdingASIA 22: 91–100.
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.
Wells, D. (2016). Blue-winged Leafbird (Chloropsis cochinchinensis). 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/58066 on 12 October 2016).