Variable Kingfisher (Ceyx lepidus) is being split: list C. dispar as Vulnerable and five other newly defined species 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.

Variable Kingfisher Ceyx lepidus is being split into C. lepidus, C. cajeli, C. dispar, C. magarethae, C. mulcatus, C. meeki, C. collectoris, C. nigromaxilla, C. gentianus, C. solitarius, C. sacerdotis and C. wallacii following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, C. lepidus (BirdLife species factsheet) was listed as Least Concern on the basis that it was not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. This species was estimated to have a very large range, and hence did not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence [EOO] of less than 20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). Despite the fact that the population trend appeared to be decreasing, the decline was not believed to be sufficiently rapid to approach the thresholds for Vulnerable under the population trend criterion (at least a 30% decline over ten years or three generations). The population size has not been quantified, but it was not believed to approach the thresholds for Vulnerable under the population size criterion (fewer than 10,000 mature individuals with a continuing decline estimated to be at least 10% over ten years or three generations, or with a specified population structure).

‘Manus Dwarf Kingfisher’ C. dispar may qualify as Vulnerable under criterion C2a(ii), on the basis that its population is estimated to include fewer than 10,000 mature individuals, forming a single subpopulation, and is inferred to be in decline owing to on-going habitat loss and degradation.

‘Dimorphic Dwarf Kingfisher’ C. margarethae is found in the central and southern Philippines (including Banton, Tablas, Romblon, Sibuyan, Semirara, Negros, Cebu, Olango, Siquijor, Camiguin Sur, Mindanao, Basilan, Malamaui, Jolo, Tawitawi and Bongao), where it occupies primary and secondary forest (Fry and Fry 1999, Kennedy et al. 2000, del Hoyo et al. 2001). It is suggested that it be listed as Near Threatened under criteria A2c+3c+4c, on the basis that it could be undergoing a moderately rapid population decline (approaching 30% over three generations [c.13 years]) owing to on-going habitat loss and degradation. The rate of decline is not thought to be more rapid because the species occurs up to lower montane elevations, where forest may be less threatened, and is able to tolerate some habitat modification.

‘Buru Dwarf Kingfisher’ C. cajeli may warrant listing as Near Threatened under criteria B1ab(ii,iii,v); C2a(ii), on the basis that it occupies a small range (with an EOO estimated at c.8,600 km2), in which suitable habitat is in decline but is not yet severely fragmented, and declines are inferred to be taking place in the species’s population, which is probably moderately small and forms a single subpopulation.

‘New Georgia Dwarf Kingfisher’ C. collectoris may warrant listing as Near Threatened under criterion C2a(ii), on the basis that the species is likely to have a small to moderately small population, of which the majority of mature individuals may form a single subpopulation, and is inferred to be in decline owing to habitat loss and degradation.

‘Makira Dwarf Kingfisher’ C. gentianus may warrant listing as Near Threatened under criterion D2, on the basis that it may be susceptible to the accidental introduction of brown tree-snake Boiga irregularis – it is apparently the only new species resulting from this taxonomic change that occurs on one small island outside the native range of brown tree-snake; see Fritts and Leasman-Tanner 2001). This invasive predator could cause a rapid decline in the species’s population, given its impacts on other bird species, although the severity of the decline is difficult to predict.

‘Sula Dwarf Kingfisher’ C. wallacii is found on the Sula Islands, where it inhabits forest, although it is not clear to what extent it relies on primary forest or tolerates secondary habitats. If the species tolerates secondary and degraded forest, it may qualify as Near Threatened under criterion C2a(i), on the basis that it has a population of fewer than 10,000 mature individuals, the majority of which forms one subpopulation, and it is in ongoing decline owing to habitat loss and degradation (Davidson et al. 1995). The proportion of the population that forms one subpopulation is however not known. If the species relies on primary forest, it may be eligible for listing under a higher threat category.

‘New Britain Dwarf Kingfisher’ C. sacerdotis is likely to warrant listing as Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under any of the IUCN criteria. An analysis of the impacts of deforestation on endemic birds in New Britain suggests that rates of forest loss within this species’s elevation range are unlikely to cause a population decline that approaches 30% over three generations (c.13 years) (see Buchanan et al. 2008).

‘New Ireland Dwarf Kingfisher’ C. mulcatus, ‘North Solomons Dwarf Kingfisher’ C. meeki and ‘Guadalcanal Dwarf Kingfisher’ C. nigromaxilla occupy very restricted ranges but are likely to warrant listing as Least Concern, on the basis that they do not approach the thresholds for Vulnerable under any of the IUCN criteria.

‘New Guinea Dwarf Kingfisher’ C. solitarius and ‘Moluccan Dwarf Kingfisher’ C. lepidus (incorporating uropygialis), which is present on Seram and the North Moluccas, are both likely to warrant listing as Least Concern, on the basis that it is not thought to approach the thresholds for Vulnerable under the IUCN criteria.

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

References:

Buchanan, G. M., Butchart, S. H. M., Dutson, G., Pilgrim, J., Steininger, M. K., Bishop, K. D. and Mayaux, P. (2008) Using remote sensing to inform conservation status assessment: Estimates of recent deforestation rates on New Britain and the impacts upon endemic birds. Biological Conservation 141: 56-66.

Davidson, P., Stones, T. and Lucking, R. (1995) The conservation status of key bird species on Taliabu and the Sula Islands, Indonesia. Bird Conservation International 5: 1–20.

del Hoyo, J., Elliott, A. and Sargatal, J. (2001) Handbook of the birds of the world, Vol 6: Mousebirds to Hornbills. Barcelona, Spain: Lynx Edicions.

Fritts, T. H. and Leasman-Tanner, D. (2001) The Brown Treesnake on Guam: How the arrival of one invasive species damaged the ecology, commerce, electrical systems, and human health on Guam: A comprehensive information source. Available Online: http://www.fort.usgs.gov/resources/education/bts/bts_home.asp

Fry, C. H. and Fry, K. (1999) Kingfishers, bee-eaters & rollers. Princeton, NJ: Princeton University Press.

Kennedy, R. S., Gonzales, P. C., Dickinson, E. C., Miranda, H. C., Jr. and Fisher, T. H. (2000) A guide to the birds of the Philippines. Oxford: 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.

Related posts:

  1. Archived 2012-2013 topics: Kofiau Paradise-kingfisher (Tanysiptera ellioti): downlist to Vulnerable or Near Threatened?
  2. Rainbow Lorikeet (Trichoglossus haematodus) is being split: list T. rosenbergii as Vulnerable and both T. weberi and T. forsteni as Near Threatened?
  3. Whistling Green-pigeon (Treron formosae) is being split: list T. formosae as Near Threatened?
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5 Responses to Variable Kingfisher (Ceyx lepidus) is being split: list C. dispar as Vulnerable and five other newly defined species as Near Threatened?

  1. Guy Dutson says:

    If the ‘Manus Dwarf Kingfisher’ C. dispar may qualify as Vulnerable , other similarly low-population density Manus endemics such as Ninox meeki, should also be listed as VU.
    ‘New Georgia Dwarf Kingfisher’ C. collectoris is common (23-63 records / km2 recorded in most forest types including and secondary lowland forest on Kolombangara by Buckingham et al1995) and has a number of large subpopulations.
    If ‘Makira Dwarf Kingfisher’ C. gentianus is at risk from the accidental introduction of brown tree-snake Boiga irregulari, so are the many tens of other bird species which are endemic to single islands across the tropical Pacific.
    Buckingham, D.L., Dutson, G.C.L. and Newman, J. (1995) The birds of Manus, Kolombangara and Makira (San Cristobal) with notes on mammals and records from other islands. Unpubl report.

  2. Joe Taylor says:

    This topic has been edited to incorporate an initial Red List assessment for C. wallacii, which will also be split from C. lepidus.

  3. Joe Taylor says:

    With reference to C. wallacii:

    Stones et al. (1997) note this taxon to be common but unobtrusive on Taliabu, and encountered it regularly in forest at some localities visited, whilst Rheindt (2010) recorded several at 0-500 m during a two-week visit to Taliabu in 2009. Rheindt (2010) also speculates that all primary forest could have been lost from Taliabu due to the widespread activities of logging companies, with some areas converted to plantations, cultivation and gardens and further conversion to agriculture expected.

    References:

    Rheindt, F. E. (2010) New biogeographical records for the avifauna of Taliabu (Sula Islands, Indonesia), with preliminary documentation of two previously undiscovered taxa. Bulletin of the British Ornithologists’ Club 130(1): 33–51.

    Stones, A. J., Lucking, R. S., Davidson, P. J. and Wahyu Raharjaningtrah (1997) Checklist of the birds of the Sula Islands (1991), with particular reference to Taliabu Island. Kukila 9: 37–55.

  4. 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. lepidus as Least Concern

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

    C. margarethae as Least Concern

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

    C. collectoris as Least Concern

    C. gentianus as Near Threatened under criterion D2

    C. wallacii as Near Threatened under criterion C2a(i)

    C. sacerdotis as Least Concern

    C. mulcatus as Least Concern

    C. meeki as Least Concern

    C. nigromaxilla as Least Concern

    C. solitarius 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.

  5. 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.

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