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.
Rufous-vented Prinia Prinia burnesii is being moved to genus Laticilla and split into L. burnesii and L. cinerascens, following the application of criteria set out by Tobias et al. (2010).
Prior to this taxonomic change, Rufous-vented Prinia was listed as Near Threatened under criteria A2c+3c+4c, on the basis that it was undergoing a moderately rapid decline due to habitat loss and degradation across certain areas of its range (BirdLife International 2016). L. burnesii, Rufous-vented Grass-babbler, (as now defined following the taxonomic change) is found mainly in Pakistan and adjacent north-west India on the plains of the Indus River, its tributaries and the riversides of western Punjab (Madge 2016a). This taxon also incorporates sub-species nepalicola, which is found only on islands in the Koshi River, Nepal, and was discovered in 2005 (Baral et al. 2007). The global population size has not been quantified, but the species has been described as locally numerous in the Indus floodplain in Pakistan and locally frequent in parts of India (Madge 2016a). The Nepalese sub-population was estimated at c.500 birds (Baral et al. 2007), but flooding in 2008 may have impacted its habitat (C. Inskipp and H. Baral in litt. 2011). There has been extensive conversion of the species’s habitat throughout its range, but it can tolerate degraded habitat to some extent. Nevertheless, the species is likely to be undergoing at least a moderate decline and so it is proposed that this species be listed as Near Threatened under criteria A2c+3c+4c.
L. cinerascens is found only on the floodplain of the Brahmaputra River in north-eastern India. The species had previously been known from the adjoining area of Bangladesh, but possibly there have been no sightings there for over 40 years (P. Thompson in litt. 2011). The species inhabits swampy low-lying plains particularly where there are large amounts of elephant grass (Madge 2016b). The population size has not been directly quantified, but the limited number of known reports suggest that this species is found at very low densities or requires a very specific microhabitat (J. Eaton in litt. 2010, R. K. Das in litt. 2011). Based on an assessment of known records, range size and descriptions of abundance this species may have a population size in the band of 10,000-19,999 mature individuals; which fits with population density estimates of closely related species of a similar size and assuming that only a proportion of its range is occupied. However, we do welcome any comments regarding this as the limited number of known reports could suggest a potentially lower population size.
There has been rapid and extensive loss and modification of tall grasslands and reedswamp throughout the range of L. cinerascens, due to drainage, conversion to agriculture, overgrazing, harvesting of grass for thatch production, inappropriate grassland management within protected areas, damming of marshes and heavy flooding in the Brahmaputra valley resulting from run-off from the increasingly denuded catchment. Therefore, the population is suspected to be in a continuing rapid decline, and so it may warrant listing as Vulnerable under criteria A2c+3c+4c.
Comments are invited on these proposed categories and further information would be welcomed.
Baral, H.S., Basnet, S., Chaudhary, B., Chaudhary, H., Giri, T. and Som G.C. 2007. A new subspecies of Rufous-vented Prinia Prinia burnesii (Aves: Cisticolidae) from Nepal. Danphe 16(4): 1-10.
BirdLife International 2016. Species factsheet: Prinia burnesii. Downloaded from http://www.birdlife.org on 18/10/2016.
Madge, S. 2016a. Rufous-vented Prinia (Prinia burnesii). 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/58578 on 18 October 2016).
Madge, S. 2016b. Swamp Prinia (Prinia cinerascens). 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/58579 on 18 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.