Seychelles White-eye (Zosterops modestus): downlist to Vulnerable?

This discussion was first published as part of the 2013 Red List update, but remains open for comment to enable reassessment in 2014.

BirdLife species factsheet for Seychelles White-eye

Seychelles White-eye Zosterops modestus is endemic to the Seychelles. It is listed as Endangered under criterion D of the IUCN Red List because it has an extremely small population.

This species was thought to survive only in three tiny areas on Mahé, Seychelles, and appeared to be declining inexorably towards extinction. In 1996, only 25-35 individuals were known (Rocamora 1997). In 1997, a previously unknown population was discovered on Conception (Rocamora 1997). In 1997, this island was estimated to hold “at least 250″ individuals (Rocamora and Francois 1999), with c.50 more on Mahé (G. Rocamora in litt. 1999). The population on Conception was estimated at c.275 (244-336) individuals in 1999 and at c.230 (189-266) in 2006, and may be fluctuating or slightly decreasing (R. Bristol in litt. 2004, G. Rocamora in litt. 2007). The population on Mahé was estimated at c.50 birds in 1997 (G. Rocamora in litt. 2007) and at c.60 birds in 2006, and appears to have slightly increased (G. Rocamora in litt. 2007). The transfer of 37 individuals from Conception to Frégate Island in 2001 and 2003 have resulted in the establishment of an estimated population of c.100 individuals there in 2007 (G. Rocamora in litt. 2007), and an estimated global total of c.400 individuals in 2007. Further translocations took place in 2007, when 25 birds were transferred to North Island, and 23 to Cousine (Rocamora and Henriette-Payet 2009). Habitat quantity and quality are both increasing (due to rat eradications and restoration programmes in the islands where the species has been transferred) (G. Rocamora in litt. 2007). Results from a monitoring programme started in 1996 indicate a moderate increase in the total population (G. Rocamora in litt. 2007), which was estimated at c.400 birds in 2007 (Rocamora and Henriette-Payet 2009). If there is sufficient evidence to suggest that there have been more than 250 mature individuals following the translocation in 2007 (for at least 5 years), and that the population is not declining, this species would be eligible for downlisting to Vulnerable under criterion D1+2 of the IUCN Red List (<1,000 mature individuals).

Further information is requested on the population size and trends of this species and comments on its proposed downlisting are welcome. 

References:

Rocamora, G. (1997) Red Data Bird: Seychelles Grey White-eye. World Birdwatch 19: 20-21.

Rocamora, G. and Francois, J. (1999) Seychelles Grey White-Eye conservation programme. Birdwatch – Bird News and Nature Notes from Seychelles 29: 20-22.

Rocamora, G. and Henriette-Payet, E. (2009) Conservation introductions of the Seychelles white-eye on predator-free rehabilitated islands of the Seychelles archipelago, Indian Ocean. In: Pritpal S. Soorae (ed.). Global re-introduction perspectives: Re-introduction case-studies from around the globe. IUCN, Gland (Switzerland).

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3 Responses to Seychelles White-eye (Zosterops modestus): downlist to Vulnerable?

  1. Joe Taylor says:

    The following comments were received from Gérard Rocamora on 23 January 2014:

    I think moving the species from EN to VU is still premature for the following reasons:

    - Even if the species may now be present in 4 or 5 islands instead of 2 initially, the number of viable populations may still be one: Conception (even if it may have increased).

    - We do not know if the Frégate population introduced in 2001 has continued to increase since 2010/11 when it was estimated at c.150 birds and another more dominant insectivorous bird (Seychelles warbler) was introduced there a year ago;

    - the North Island one is growing but slowly, our latest figures (June 2013; October 2013) for the North Island population (introduced in 2007) are c. 70-75 birds;

    - the introduction on Cousine has clearly failed (no more than 5 birds there a few months ago),

    - the relictual Mahé population has decreased over the last 3-4 years (less than 40 birds censused over the last 2 years).

    So before downlisting of the species from EN to VU can be done, I think that we need:

    1 – To confirm and update information on the population size of the Conception source population, and that it has increased to over 300 birds following the eradication of Brown rats in 2007. Last point count monitoring data is from December 2012 but I still need to analyse it.

    2 – To undertake a pop. estimate of the current population size of the Frégate population (introduced in 2001), and check that it is now over 200 individuals (the lowest figure we ever reached on Conception after our 2007 transfers), and that therefore the species has now TWO viable and self-sustaining populations instead of one.

    3 – Conduct at least two other transfers to rat-free islands.

    4- Continue to monitor the NI population and confirms that it continues to grow.

    5- Confirm the status of the species on Cousine (whether the species is still there or not).

  2. Andy Symes says:

    Preliminary proposals

    Based on available information, our preliminary proposal for the 2014 Red List is to pend the decision on Seychelles White-eye Zosterops modestus and keep this discussion open until early 2015, while leaving the current Red List category unchanged in the 2014 update.

    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 categorisation to be put forward to IUCN

    Following further review, there has been no change to our preliminary proposal for the 2014 Red List status of this species.

    This discussion will remain open for further comments and information until early 2015, and the current Red List category will remain unchanged in 2014.

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