Archived 2017 topics: Maccoa Duck (Oxyura maccoa): request for information

This discussion was first published as part of the 2016 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2017 Red List update this post remained open and the date of posting was updated.

BirdLife species factsheet for Maccoa Duck: http://www.birdlife.org/datazone/species/factsheet/22679820

Maccoa Duck is currently listed as Near Threatened owing to its moderately small population size and ongoing declines resulting from a variety of threats.

This species is found in two distinct populations in Africa; its northern population is found in in Eritrea, Ethiopia, Kenya and Tanzania; and the southern population is in Angola, Botswana, South Africa, Namibia and Zimbabwe. The total population for southern Africa is approximately 7,000-8,250 individuals, and the population estimate for East Africa has been given at 2,000-3,500 individuals (Berruti et al. 2005, 2007), with the Ethiopian population maybe as high as 500-2,000. However, the northern population has undergone a severe decline – up to 50% during the late 1990s and early 2000s, and in Kenya only 14 individuals were observed during a survey from December 2014 to July 2015 (G. Kung’u in litt. to P. Ndang’ang’a 2016). The Kenyan population may now be <50 individuals (D. Turner in litt. to P. Ndang’ang’a 2016); and there may only be a maximum of 100 individuals in Tanzania (D. Turner in litt to P. Ndang’ang’a 2016). Thus the East African population may in fact be far smaller than previous estimates and in fact may be <300 individuals (D. Turner in litt. to P. Ndang’ang’a 2016). The larger, southern population has been thought to be stable (Berruti et al. 2005), but declines may have begun (Berruti et al. 2007)

In the 2015 Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland (Taylor 2015) the species is listed as regionally Near Threatened under criterion C1, with a population estimated at 4,500-5,500 mature individuals which is decreasing at an unknown rate.

The total rate of decline for the species is currently suspected to be slow. However, given that the population in East Africa may now be <300 individuals, the total population is suspected to be fewer than 10,000 individuals, and so fall in the range of 2,500-9,999 individuals; roughly equivalent to 1,650-6,700 mature individuals. With more accurate figures for declines this species may therefore qualify as Vulnerable under criterion C1 if estimated to be declining by >10% in three generations (18 years).

We request any further information regarding population size estimates and population trends for this species to help decide whether this species warrants uplisting.

Reference

Berruti, A.; Baker, N.; Buijs, D.; Colahan, B. D.; Davies, C.; Dellegn, Y.; Eksteen, J.; Kolberg, H.; Marchant, A. H.; Mpofu, Z.; Nantongo-Kalundu, P.; Nnyiti, P.; Pienaar, K.; Shaw, K.; Tyali, T.; van Niekerk, J.; Wheeler, M. J. 2005. International Maccoa Duck Oxyura maccoa Action Plan.

Berruti, A.; Baker, N.; Buijs, D.; Colahan, B.D.; Davies, C.; Dellegn, Y.; Eksteen, J.; Kolberg, H.; Marchant, A.; Mpofu, Z.; Nantongo-Kalundu, P.; Nnyiti, P.; Pienaar, K.; Shaw, K.; Tyali, T.; van Niekerk, J.; Wheeler, M.J.; Evans, S.W. 2007. International Single Species Action Plan for the conservation of the Maccoa Duck Oxyura maccoa. AEWA, Bonn.

Taylor, M. R.; Peacock, F.; Wanless, R. M. 2015. The 2015 Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. BirdLife South Africa, Johannesburg.

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5 Responses to Archived 2017 topics: Maccoa Duck (Oxyura maccoa): request for information

  1. Jean-Yves Mondain-Monval & Pierre Defos du Rau says:

    On 12 September 2015, a low minimum of 20 but possibly more Maccoa ducks on Small Momela Lake in Arusha NP, Tanzania.
    (Sorry, we should have posted that data before on the Tanzania Bird Atlas project; we hadn’t realize it had become that rare)

  2. James Westrip (BirdLife) says:

    Based on available information, our proposal for the 2016 Red List would be to pend the decision on this species and keep this discussion open until 2017, while leaving the current Red List category unchanged in the 2016 update.

    Final 2016 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

  3. Ian Riddell says:

    Of erratic occurrence in Zimbabwe and mainly in the west. Numbers are low, often <10 at any site. Aisleby (Umguza Dam) in Bulawayo is the main site and numbers fluctuate widely. 132 on 21 October 2007 is exceptional and likely a country record.
    Would appear to be less extensively distributed now which could indicate a decline.

  4. The analysis of International Waterbird Census (IWC) data from Southern Africa indicated a population growth rate of 0.9461 (SE 0.0151) for the period of 1999-2012 (Nagy et al. 2014 https://www.wetlands.org/download/7762/). Preliminary results of the trend analysis based on the IWC data from Southern Africa for the period of 1991-2015 shows an overall stable population (growth rate: 1.0093, SE 0.0243) for the 25 years period. However, it confirms that the earlier increase was followed buy a rapid decline in the last 10 years (0.9341, SE 0.0805, n.s.) that suggests c. 78% decline over the last 10 years (Nagy & Langendoen in prep). This agrees well with the results of the comparison of the results of the first and second South African Bird Atlas Project (Underhill & Brooks, 2016 http://bo.adu.org.za/pdf/BO_2016_07-088.pdf)

  5. Andy Symes (BirdLife) says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2017 Red List would be to list:

    Maccoa Duck as Vulnerable under criterion A4.

    There is now a period for further comments until the final deadline of 4 August, after which the recommended categorisations will be put forward to IUCN.

    Please note that we will then only post final recommended categorisations on forum discussions where these differ from the initial proposal.

    The final 2017 Red List categories will be published on the BirdLife and IUCN websites in early December, following further checking of information relevant to the assessments by both BirdLife and IUCN.

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