Archived 2012-2013 topics: Sao Tome Short-tail (Amaurocichla bocagei): downlist to Near Threatened or Least Concern?

BirdLife species factsheet for Sao Tome Short-tail Sao Tome Short-tail Amaurocichla bocagei is restricted to São Tomé, São Tomé e Príncipe, where it occurs in the central and southern parts of the island. Known from only six records prior to 1928, it was rediscovered in 1990, in the valleys of the Xufexufe and Ana Chaves rivers (4.1-6.3 pairs and 5.6 pairs per 1 km of river, respectively) (Atkinson et al. 1991). In 1997, it was reported to be seen and heard in almost every forested river basin in the Agua Ribeira near Formoso Grande and around São Miguel (S. d’Assis Lima in litt. 1997). It is currently listed as Vulnerable under criterion D1 because it was thought to have a small population, estimated at 250-999 mature individuals (based on an assessment of known records, descriptions of abundance and range size), given the limited area of suitable habitat believed to be available to it. The overall population is thought to be stable, although it is reported that the species has deserted areas of habitat near Bombaim (F. Olmos in litt. 2007), perhaps indicating a local decline. It was once thought to be restricted to forest below 600 m (Jones and Tye 2006) and associated with water (Atkinson et al. 1991), but it has since been found to occur at over 1,000 m in the headwaters of the Ana Chaves river (F. Olmos in litt. 2007), to be fairly common in some montane forests above 1,300 m (Maia and Alberto 2009, Olmos and Turshak 2010) and show no association with water in either low elevation or montane forest (Olmos and Turshak 2010). The species appears to be more widespread than previously thought, necessitating an upwards revision of its population estimate. If the population is now estimated to number >1,000 mature individuals, the Sao Tome Short-tail would qualify for downlisting to Near Threatened (if it approaches the population threshold for Vulnerable)  or Least Concern on the IUCN Red List. Information is requested on the population size and distribution of this species, and comments on the proposed downlisting are welcome. References: Atkinson, P., Peet, N. and Alexander, J. (1991) The status and conservation of the endemic bird species of Sao Tomé and Príncipe, West Africa. Bird Conservation International 1: 255-282. Jones, P. and Tye, A. (2006) The Birds of São Tomé & Príncipe with Annobón: Islands of the Gulf of Guinea. An Annotated Checklist. BOU Checklist No. 22. Oxford, UK: British Ornithologists’ Union & British Ornithologists’ Club. Maia, H. A. and Alberto, A. C. (2009) The occurrence of São Tomé Short-tail Amaurocichla bocagei and Newton’s Fiscal Lanius newtoni. Bulletin of the British Ornithologists’ Club 129(4): 213-216. Olmos, F. and Turshak, L. G. (2010) Bird observations from São Tomé: Monte Carmo as a priority conservation site. Bulletin of the African Bird Club 17(1): 54-65.

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4 Responses to Archived 2012-2013 topics: Sao Tome Short-tail (Amaurocichla bocagei): downlist to Near Threatened or Least Concern?

  1. Due to the scarcity of records for this species and a big uncertainty surrounding its ecology, I think it is advisable to keep it as Vulnerable until particular aspects are clarified, such as distribution/area of occupancy, ecological requirements, population size (across the entire range) and relationship with exotic species (such as cats and rats).

    In the BirdLife species factsheet it is said to be distributed over 340km2, but its presence has not been confirmed in a large portion of this range, and it is absent or very rare in part of that range; the area around Lagoa Amélia is one of the best studied in the island and there are very few records for the species over that part of the range (Martim Melo, pers. comm.). Therefore, the high densities (around 5 pairs per 1 km of river) calculated in the valleys of the Xufexufe and Ana Chaves rivers (Atkinson et al. 1991) should not be extrapolated for the entire range of the species.

    Even if recent records have challenged the idea that the species is a lowland specialist associated with watercourses, this will not increase its distribution much. Most forest suitable for this species will still be found at low altitudes, and close to water (annual rainfall in these forests can be as high as 7000mm).

    Given the lack of data to access population size, I argue that the species should instead be kept as Vulnerable following criteria B1a; B1b(iii); B2a; B2b(iii). It is difficult to estimated population size, but the species certainly falls under those limits for extent of occurrence and area of occupancy, and it can easily be conceived that it does not occur in more than 10 locations, and that the area, extent and quality of the habitat is declining. In fact, following the IUCN definition for location, as an area in which a single event can rapidly affect all individuals present, it can even be considered that the species is restricted to a single location (the best preserved forest patches within the Obô Natural Park), which is known to be loosing extent and quality of habitat for the species (Jones et al., 1991).

    Jones, P.J., Burlison, J.P. & Tye, A. (1991) Conservação dos ecossistemas florestais na República Democrática de São Tomé e Príncipe. International Union for the Conservation of Nature and Natural Resources, Gland.

  2. Joe Taylor says:

    The following comments were received from Martin Dallimer on 16 August 2013:

    I strongly agree with Ricardo’s comment. The initial descriptions of the species being restricted to lowland areas near watercourses may have been mistaken, but this does not necessarily mean that the threat status of the species should be down-graded. For instance, we do know that records of the species are relatively scarce at higher altitudes – in a systematic survey of primary forest sites spanning lowland, montane and mist forest, the short-tail was only recorded in lowland areas (Dallimer et al 2009), although we did also encounter the species outside the formal survey periods at higher altitudes (Dallimer et al. 2003). Lowland forest is therefore likely to remain key for the persistence of the species. Until we have more systematic knowledge of the species, its habitat requirements, threats and distribution I would recommend that the current threat status is retained.

    Dallimer M, King T, Atkinson RJ. (2003) A high altitude sighting of the São Tomé short-tail Amaurocichla bocagei. Malimbus, 25, 101-103.

    Dallimer M, King T, Atkinson RJ. (2009) Pervasive threats within a protected area: conserving the endemic birds of São Tomé, West Africa. Animal Conservation, 12, 209-219.

  3. Fábio Olmos says:

    I agree with Ricardo and Martin. The species seems to have a patchy distribution, being easily found in some areas while absent or occasional in similar habitat elsewhere, so assuming a homogeneous density over the assumed range does not reflect reality. On top of that recent clearing of second-growth and abandoned oil-palm plantations to plant new oil-palm has resulted in illegal logging in areas where the species occur (Monte Carmo), with resulting loss of habitat quality, and may lead to further encroachment. I can’t see this species as considered LC

  4. Ricardo Rocha says:

    I fully agree with all that has been said by Ricardo, Martin and Fábio.

    During my MSc thesis I undertook two and a half months of extensive work around Lagoa de Santa Amelia and I have never encountered any individuals of the species.
    My only record of the A. bocagei comes from an area close to where Martin had previously observed and individual in 2001. The observation was of a fledgling being feed by both parents (http://www.arkive.org/sao-tome-short-tail/amaurocichla-bocagei/image-G55363.html), confirming that the reproduction activity of the species is extended to montane rainforest.

    For the same reasons previously presented by all contributors I suggest the species to continue to be categorized as Vulnerable.

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