Archived 2014 discussion: Grey Nightjar (Caprimulgus indicus) is being split: list C. phalaena as Near Threatened?

This is part of a consultation on the Red List implications of extensive changes to BirdLife’s taxonomy for non-passerines

Lynx Edicions and BirdLife International will soon publish 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 1 of the checklist (for non-passerines) will begin to be incorporated into the 2014 Red List update, with the remainder, and those for passerines (which will appear in volume 2 of the checklist), 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.

Grey Nightjar Caprimulgus indicus is being split into C. indicus, C. jotaka and C. phalaena, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, C. indicus (BirdLife species factsheet) was listed as being of Least Concern, on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN Red List criteria.

C. phalaena is endemic to Palau, where it inhabits mangroves and edges of lowland forest, damp, shady forests and mangrove swamps (Holyoak 2001). It was previously described as uncommon and declining (Pratt et al. 1980, 1987). This implies that the species could qualify as Endangered under criterion C2a(ii), on the basis that it is thought to have a very small and declining population, probably numbering fewer than 2,500 mature individuals and forming a single subpopulation. However, it is suggested here that the species be listed as Near Threatened under criterion C2a(ii), because it is not clear whether the population is currently in decline, as the species is probably tolerant of some habitat modification, and the impacts of existing levels of land-use change and habitat degradation may only have minimal impacts on the species.

C. jotaka is a widespread migrant, being present year-round in parts of the Himalayas, South-East Asia and southern Japan, with migratory breeding populations reaching the western Himalayas, north-eastern Russia and northern Japan, and non-breeding populations distributed south to Java. It was described as a local but not uncommon summer visitor to the Japanese Islands of Kyushu, Shikoku, Honshu and Hokkaido (del Hoyo et al. 1999) and a fairly common passage migrant and winter visitor throughout Malaysia (del Hoyo et al. 1999). Although described as a local and uncommon breeding bird in Thailand, it was not considered to be at risk there (Lekagul and Round 1991). It is likely to be listed as being of Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.

C. indicus (as defined following the taxonomic change) is widespread in the Indian Subcontinent, where it inhabits forests, woodlands and semi-open habitats (Holyoak 2001). It has previously been described as locally common in its small range in north-east Pakistan (Roberts 1991), fairly common in Nepal (Inskipp and Inskipp 1985), locally common in Sri Lanka (del Hoyo et al. 1999) and local in Bangladesh (Harvey 1990). It is likely to be listed as being of Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria.

Comments on these suggested categories and further information would be welcomed.

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (1999) Handbook of the birds of the world, Vol 5: Barn-owls to Hummingbirds. Barcelona, Spain: Lynx Edicions.

Harvey, W. G. (1990) The Birds of Bangladesh. Dhaka: The University Press.

Holyoak, D. T. (2001) Nightjars and their Allies. Oxford, UK: Oxford University Press.

Inskipp, C. and Inskipp, I. (1985) A Guide to the Birds of Nepal. London, UK and Sydney, Australia: Croom Helm.

Lekagul, B. and Round, P. D. (1991) A Guide to the Birds of Thailand. Bangkok, Thailand: Saha Karu Bhaet.

Pratt, H. D., Engbring, J., Bruner, P. L. and Berrett, D. G. (1980) Notes on the taxonomy, natural history, and status of the resident birds of Palau. Condor 82: 117-131.

Pratt, H. D., Bruner, P. L. and Berrett, D. G. (1987) The Birds of Hawaii and the Tropical Pacific. Princeton, NJ: Princeton University Press.

Roberts, T. J. (1991) The Birds of Pakistan. Vol. 1. Regional Studies and Non-passeriformes. Oxford, UK: Oxford University Press.

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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3 Responses to Archived 2014 discussion: Grey Nightjar (Caprimulgus indicus) is being split: list C. phalaena as Near Threatened?

  1. Pratap Singh says:

    Caprimulgus jotka and C. indicus, which are distributed in India, are commonly seen/heard in suitable areas in Himalayas and central and peninsular India, and therefore deserve to be in Least concern category.

  2. Joe Taylor says:

    Preliminary proposals

    Based on available information and comments posted above, our preliminary proposals for the 2014 Red List would be to treat:

    C. indicus as Least Concern

    C. phalaena as Near Threatened under criterion C2a(ii)

    C. jotaka as Least Concern

    There is now a period for further comments until the final deadline of 31 March, after which recommended categorisations will be put forward to IUCN.

    The final Red List categories will be published on the BirdLife and IUCN websites in mid-2014, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Andy Symes says:

    Recommended categorisations to be put forward to IUCN

    Following further review, there have been no changes to our preliminary proposals for the 2014 Red List status of these species.

    The final categorisations will be published later in 2014, following further checking of information relevant to the assessments by BirdLife and IUCN.

Comments are closed.