Archived 2014 discussion: Ostrich (Struthio camelus) is being split: list S. molybdophanes as Near Threatened or Vulnerable?

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.

Ostrich Struthio camelus is being split into S. camelus and S. molybdophanes, following the application of criteria set out by Tobias et al. (2010).

Prior to this taxonomic change, S. camelus (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 criteria.

S. molybdophanes is found in Ethiopia, Somalia, Djibouti and Kenya, where it occurs in a range of habitat types from semi-desert to dense thornbush (Davies 2002, Ash and Atkins 2009).

Ash and Atkins (2009) document threats to and apparent declines in Struthio taxa in Ethiopia and Eritrea. Their eggs are used as ornaments, water containers and symbols or protective devices on churches and graves, birds are shot for target practice, food, leather and feathers, and chased to exhaustion or death by drivers. Numbers have noticeably decreased since the late 1980s, with total disappearance from some areas, although flocks of 40 are still seen in the southern Danakil (Ash and Atkins 2009).

It is possible that S. molybdophanes has undergone a moderately rapid decline (approaching 30%) over the past 50 years (estimate of three generations), in which case it is likely to qualify as Near Threatened under criterion A. If evidence suggests that the rate of decline has been 30-49% over this time period, the species could qualify as Vulnerable. A decline of 50% or more over three generations would imply that the species should be listed as Endangered. Comments and further information are requested, including whether the population is likely to approach or meet the population size threshold of 10,000 mature individuals, the probable subpopulation structure (number of mature individuals in the largest subpopulation or percentage of all mature individuals in one subpopulation), as well as the likely population trend over the next 50 years.

S. camelus (as defined following the taxonomic change and incorporating all other forms) is widespread in Africa and, although characterised as frequent to abundant throughout most of its range and common in East Africa, it is thought to be in decline in many areas (del Hoyo et al. 1992). Its numbers and range are said to have been diminished in West and North Africa, while the wild population in southern Africa has contracted to the north-west of its former range, with feral birds elsewhere (hybrids of indigenous subspecies australis and introduced camelus). Hunting and egg collecting were major threats in the 20th century, along with habitat loss, which is now the primary threat affecting the species (del Hoyo et al. 1992).

Despite evidence of widespread declines, the species may be of Least Concern, on the basis that it does not approach the thresholds for Vulnerable under any of the IUCN criteria. However, it would probably warrant listing as Near Threatened under criterion A if evidence were to suggest a decline approaching 30% over 50 years. Comments and further information are requested, including the likely population trend over the next 50 years.

References:

Ash, J. and Atkins, J. (2009) Birds of Ethiopia and Eritrea: an atlas of distribution. London, UK: Christopher Helm.

Davies, S. J. J. F. (2002) Ratites and Tinamous: Tinamidae, Rheidae, Dromaiidae, Casuariidae, Apterygidae, Struthionidae. Oxford, UK: Oxford University Press (Bird Families of the World Series).

del Hoyo, J., Elliot, A. and Sargatal, J. (1992) Handbook of the birds of the world, vol 1: Ostrich to Ducks. 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.

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2 Responses to Archived 2014 discussion: Ostrich (Struthio camelus) is being split: list S. molybdophanes as Near Threatened or Vulnerable?

  1. Joe Taylor says:

    Preliminary proposals

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

    S. camelus as Least Concern

    S. molybdophanes as Vulnerable under criteria A2d+3d+4d

    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.

  2. 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.