Archived 2016 topics: Blue-winged Leafbird (Chloropsis cochinchinensis) is being split: list C. cochinchinensis as Near Threatened?

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.

References:

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).

This entry was posted in Archive, Asia, Indonesian cagebird trade, Taxonomy and tagged , , , , , , , , , , , . Bookmark the permalink.

4 Responses to Archived 2016 topics: Blue-winged Leafbird (Chloropsis cochinchinensis) is being split: list C. cochinchinensis as Near Threatened?

  1. James Eaton says:

    This species is rarely observed away from Halimun-Salak National Park and Gunung Ijen, being recorded in small numbers elsewhere on Java. It is encountered only in small numbers in trade, presumably indicating a small wild population. Many historical sites (ie Carita) no longer have populations, I would strongly suggest a higher uplisting, possibly even to Endangered, pending further work.

  2. Rob Martin (BirdLife International) says:

    Given the number of sites, area in which the species is likely to persist, and an application of the lower threshold of density estimates for the pre-split species elsewhere it is not believed that the population is likely to be fewer than 10,000 mature individuals, hence the species is not considered to meet the thresholds for listing under Criterion C. The large range of the species indicates that it does not approach the thresholds for listing under Criterion B, additionally criteria D and E are not applicable. The potentially applicable criteria is that of population decline, Criterion A.
    Recent reports indicate that the species is still present at Carita (Upton, N. 2016. eBird Checklist S31742855. Available at: http://ebird.org/ebird/view/checklist/S31742855), and remains present at least at Gunung Ciremai, Halimun-Salak, Gunung Merapi, Ijen, Gunung Arjuna/Arjuno and Baluran (eBird 2016: http://ebird.org/ebird/map/blwlea1?neg=true&env.minX=100.50306789233719&env.minY=-10.23165605598529&env.maxX=121.59681789233719&env.maxY=-0.5306069522317589&zh=true&gp=true&ev=Z&mr=1-12&bmo=1&emo=12&yr=last10). As noted above, the species has been considered rare where it occurs for some time. The current fashion for leafbirds in the cage bird trade and the observations of the species being regularly targeted, presumably across the whole range, would suggest a decline is occurring. Judging the suspected rate of a decline for which there is only circumstantial evidence is extremely difficult, but the relatively small numbers thus far reported from market surveys and lack of evidence of local extinctions within the most recent three generations would suggest currently it would not be characterised as a rapid or moderately rapid decline exceeding 30%. Further information providing more firm evidence of a rate of decline, perhaps a repeat of surveys such as those carried out by Bas van Balen in the 1990s and a comparison of encounter rates or abundance estimates would be of huge value. Future updates of the species would obviously incorporate such information.

    Preliminary Proposals

    Based on available information, our preliminary proposal for the 2016 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.
    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 those in 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.

  3. Bas van Balen says:

    Leafbirds have long been moderately popular cage birds until Greater Green became suddenly extremely popular because of its talent for imitating, and better song. Most likely Blue-winged will follow up GG as popular cage bird when stocks in the wild of GG have been depleted and people have developed a taste for leafbirds. An overall survey, especially where few birders come (e.g., the extensive teak forests in central and east Java) would be useful. Near-threatened may be OK now, but this may change very soon.

  4. Rob Martin (BirdLife International) says:

    Comments have been received from Burung Indonesia (in litt. 2016) supporting the uplisting of this species to Near Threatened.

Comments are closed.