Archived 2016 topics: Banded Broadbill (Eurylaimus javanicus) is being split: list E. javanicus as Vulnerable and E. harterti as Least Concern?

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.

Banded Broadbill Eurylaimus javanicus is being split into E. javanicus and E. harterti, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, E. javanicus (BirdLife species factsheet) was listed as Least Concern, on the basis that it was not considered to approach any of the thresholds for listing as Vulnerable. The pre-split species was characterised as uncommon to locally common in Indochina, locally common in the south of the range but rare on Java and in Brunei (Bruce (2016). Predominately a lowland forest species, including logged and secondary forest, but also found in edge habitats, overgrown rubber plantations and mature gardens and parks (Bruce 2016). Density estimates include 10 individuals per km2 in primary forest in Sarawak (Bruce 2016).

E. javanicus (as defined following the taxonomic changes) is found on the island of Java, where it has been recorded from several protected areas but appears to be scarce and absent from many locations. It is considered to occur mostly between 500-900 m in altitude, but has been recorded up to 1,500 m (Bruce 2016). Forest cover on Java has been reduced to a largely isolated fragments of mid- to upper altitude forest, most of which lies within protected areas. The species has been recently recorded from Gunung Gede-Pangrango and Gunung Halimun-Salak National Parks, and also from Carita and Rawa Dano, all in western Java (eBird records) and Mittermeier et al. (2014) did not record the species from central or east Java.

Eurylaimus javanicus is seemingly rarely targeted for the cagebird trade, and was not recorded in an inventory of the largest markets in Jakarta carried out in 2014 (Chng et al. 2015). Some loss of habitat within the altitudinal range of the species is continuing, particularly around the lower edges of protected areas and at Carita. Unfortunately there is no population information for the species, and given the very patchy distribution it is difficult to extrapolate from the extent of occurrence calculated for this species. Given the limited number of sites, and scarcity within those sites the species is considered likely to have a fairly small population size, which may well be near to the threshold for listing as Vulnerable (fewer than 10,000 mature individuals, coupled with an ongoing decline and likely multiple separate subpopulations with fewer 1,000 mature individuals in the largest).

Therefore it is proposed that E. javanicus is listed as Near Threatened, on the likelihood that the species approaches the threshold for listing as Vulnerable under criterion C2a(i).

E. harterti is proposed to be listed as Least Concern, on the basis that it is not considered to approach any of the thresholds for listing as Vulnerable, having an extremely large range and tolerating edge habitats, overgrown rubber plantations and mature gardens and parks.

Comments are invited on these proposed categories and further information would be welcomed. In particular, information on whether the population size can be securely placed below 10,000 mature individuals (implying consideration of listing the species as Vulnerable) or, conversely, considerably above 10,000 mature individuals (implying consideration of listing the species as Least Concern) is needed.

 

References:

Bruce, M. D. 2016. Banded Broadbill (Eurylaimus javanicus). 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/56346 on 13 September 2016).

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.

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.

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.

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2 Responses to Archived 2016 topics: Banded Broadbill (Eurylaimus javanicus) is being split: list E. javanicus as Vulnerable and E. harterti as Least Concern?

  1. James Westrip (BirdLife) says:

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

    E. harterti as Least Concern.

    E. javanicus as Near Threatened under criterion C2a(i).

    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.

  2. Rob Martin (BirdLife International) says:

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

Comments are closed.