Archived 2014 discussion: Piping Hornbill (Bycanistes fistulator) is being split: list B. fistulator 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.

Piping Hornbill Bycanistes fistulator is being split into B. fistulator and B. sharpii following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, B. fistulator (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 an extremely large range, and hence did not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence 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). The population trend appeared to be stable, and hence the species did not 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).

B. fistulator (as defined following this taxonomic change) is found in West Africa from Senegal east to western Nigeria, where it inhabits lowland primary evergreen forest, gallery forest, mangroves and swamp forest, as well as secondary forest and plantations (del Hoyo et al. 2001). It may warrant listing as Near Threatened under criteria A2cd+3cd+4cd, on the basis that it could be undergoing a moderately rapid population decline (approaching 30% over three generations [c.57 years]) owing to on-going habitat loss and potential hunting pressure. The rate of decline is not thought to be more rapid because the species appears to adapt well to some modified habitats.

B. sharpii (incorporating duboisi) is found in Central-west Africa, from eastern Nigeria, south to north-western Angola and east to South Sudan, western Uganda and eastern Democratic Republic of Congo, where it inhabits the same range of habitats as the nominate part of the split (del Hoyo et al. 2001). B. sharpii 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.

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

References:

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.

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 2011-2012 topics: Yellow-casqued Hornbill (Ceratogymna elata) and Brown-cheeked Hornbill (Bycanistes cylindricus): request for information
  2. Archived 2014 discussion: Tahiti Kingfisher (Todiramphus veneratus) is being split: list T. youngi as Endangered?
  3. Archived 2011-2012 topics: Knobbed Hornbill (Aceros cassidix) and Sulawesi Hornbill (Penelopides exarhatus): uplist to Near Threatened?
  4. Archived 2014 discussion: White-crested Hornbill (Tropicranus albocristatus) is being split: list T. albocristatus as Near Threatened?
  5. Archived 2014 discussion: Dwarf Black Hornbill (Tockus hartlaubi) is being split: list T. hartlaubi as Near Threatened?
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5 Responses to Archived 2014 discussion: Piping Hornbill (Bycanistes fistulator) is being split: list B. fistulator as Near Threatened?

  1. Hugo Rainey says:

    The split seems reasonable based on plumage differences.

    The threat status also seems reasonable as, although it has a catholic choice of habitats, it is not often abundant outside intact forest.

  2. Jeremy Lindsell says:

    I would say this is a marginal call. In Sierra Leone I only ever tended to see this species outside decent forest, commuting around overgrown farmbush so not thought of it being so dependent on intact forest. Our survey work in Gola showed it to be most abundant in more degraded forest and at forest edges and clearings and less common in the most intact areas.

  3. Andy Symes says:

    The following comments were received from Françoise Dowsett-Lemaire on 20 August 2013:

    Bycanistes fistulator. A split from sharpii is very premature as the situation in the Dahomey Gap has not been looked into in any detail. Intergrades with sharpii in C. Nigeria and is expected to do so elsewhere (Dahomey Gap), as sharpii-type birds are recorded in the Dahomey Gap. Specimens need to be re-examined.
    In Ghana, fistulator is common in two areas: the coastal belt and forests a short way inland, whether in wildlife reserves or outside. It is again common further north, mainly in the forest/savanna transition zone, where it is largely protected inside wildlife reserves (Digya, Kogyae, Kyabobo). The fact that it remains common on the coast close to cities suggests that hunting is not as much a problem as with the large frugivorous hornbills. Probably best left as a “least concern” species. It also has a much bigger range than the larger hornbills, as it extends into the forest/savanna transition zones. In any case, the taxonomic status remains unresolved until the situation has been studied in the Dahomey Gap. Sharpii and fistulator have identical voice and ecology.

  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:

    B. fistulator as Least Concern

    B. sharpii 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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