Solomons Hawk-owl (Ninox jacquinoti) is being split: list N. malaitae and N. roseoaxillaris as Vulnerable and N. granti 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.

Solomons Hawk-owl Ninox jacquinoti is being split into N. jacquinoti, N. malaitae, N. roseoaxillaris and N. granti, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, N. jacquinoti (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.

N. malaitae is endemic to the island of Malaita in the Solomon Islands, where it is known from at least two specimens collected in forest at 900-1,200 m (Dutson 2011). It has been described as uncommon or rare, and possibly threatened by the loss of lowland forests, thus potentially categorised as Vulnerable (Dutson 2011). In line with this, it is suggested that this species be listed as Vulnerable under criterion C2a(ii), on the basis that it has a small population, probably including fewer than 10,000 mature individuals, all in a single subpopulation, which is inferred to be in continuing decline owing to on-going encroachment and degradation of forest.

N. roseoaxillaris is endemic to the island of Makira in the Solomon Islands, and may also occur on Ugi and Santa Catalina (Dutson 2011). It inhabits forest up to 600 m, with some roosting in thickets, and  has been described as uncommon or rare, being known from only a few records, and may be threatened by deforestation in the lowlands, with a likely categorisation of Vulnerable (Dutson 2011). It is suggested that this species be listed as Vulnerable under criterion C2a(ii), on the basis that it has a small population, probably including fewer than 10,000 mature individuals, all in a single subpopulation, with continuing population declines projected in the near future owing to expected levels of logging, as much of lowland Makira is under existing or planned timber licences (Danielsen et al. 2010).

N. granti is endemic to the island of Guadalcanal in the Solomon Islands, where it inhabits forest, including edges and patches of forest, up to 1,500 m, with some roosting in thickets (Dutson 2011). It has been described as fairly common and not threatened (Dutson 2011). However, it is suggested that this species be listed as Near Threatened under criterion C2a(ii), on the basis that it is likely to have a small population, probably including fewer than 10,000 mature individuals, all in a single subpopulation, which may be stable or in slow decline, as there is limited encroachment and habitat degradation at the lower levels of its elevation range, with the species showing some tolerance of habitat modification and fragmentation and occurring in montane areas where forest is expected to be comparatively more secure, thus overall impacts are probably minimal.

N. jacquinoti (as defined following the taxonomic change, and incorporating all other forms: eichhorni, mono, and floridae) is found in the western Solomon Islands, from Bougainville to the Florida Islands (potentially also occurring on Kolombangara, New Georgia and Vonavona); it inhabits forest, but prefers forest edge and occurs in gardens with large trees, up to at least 2,000 m (Dutson 2011).

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.

References:

del Hoyo, J., Elliott, A. and Sargatal, J. (1997) Handbook of the birds of the world, Vol 4: Sandgrouse to Cuckoos. Barcelona, Spain: Lynx Edicions.

Danielsen, F., Filardi, C. E., Jønsson, K. A., Kohaia, V., Krabbe, N., Kristensen, J. B., Moyle, R. G., Pikacha, P., Poulsen, M. K., Sørensen, M. K., Tatahu, C., Waihuru, J. and Fjeldså,J. (2010) Endemic avifauna biodiversity and tropical forest loss in Makira, a mountainous Pacific island. Singapore Journal of Tropical Geography 31: 100-114.

Dutson, G. (2011) Birds of Melanesia: The Bismarcks, Solomons, Vanuata and New Caledonia. London, UK: Christopher Helm (Helm Field Guides).

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 2010-2011 topics: Solomon Islands Frogmouth (Rigidipenna inexpectata): uplist to Near Threatened or Vulnerable?
  2. Rainbow Lorikeet (Trichoglossus haematodus) is being split: list T. rosenbergii as Vulnerable and both T. weberi and T. forsteni as Near Threatened?
  3. White-throated Eared-nightjar (Eurostopodus mystacalis) is being split: list E. exul as Critically Endangered (Possibly Extinct) and E. nigripennis as Vulnerable?
  4. New Zealand Snipe (Coenocorypha aucklandica) is being split: list C. iredalei as Extinct, C. huegeli as Vulnerable and C. aucklandica as Near Threatened?
  5. New Zealand Pigeon (Hemiphaga novaeseelandiae) is being split: list H. chathamensis as Vulnerable and H. novaeseelandiae as Near Threatened?
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3 Responses to Solomons Hawk-owl (Ninox jacquinoti) is being split: list N. malaitae and N. roseoaxillaris as Vulnerable and N. granti as Near Threatened?

  1. Guy Dutson says:

    Agreed, although granti is certainly decreasing given the ongoing degradation and loss of forest

  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:

    N. jacquinoti as Least Concern

    N. malaitae as Vulnerable under criterion C2a(ii)

    N. roseoaxillaris as Vulnerable under criterion C2a(ii)

    N. granti as Vulnerable under criterion C2a(ii)

    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.

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