Archived 2016 topics: Montserrat Oriole (Icterus oberi): downlist to Vulnerable?

Montserrat Oriole Icterus oberi is endemic to Montserrat (to UK) where it has an extremely small range. It is currently listed as Critically Endangered under criterion B1ab due to a rapid population decline between 1997 and 2000 (Arendt et al. 1999 , Bowden et al. 2001 , Hilton et al. 2003), probably caused by the impact of volcanic activity on Montserrat that was ongoing between 1995 and 2013.

Following the destruction of the majority of its habitat in 1997, the Montserrat Oriole has been restricted to two small forest remnants on Montserrat: the Centre Hills (11 km2) and a smaller remnant (2.7 km2) in the South Soufrière Hills (Allcorn et al. 2012).

The Centre Hills has now been designated a protected area and development is not permitted within its marked boundaries (P. Atkinson in litt. 1998, 1999). A Species Action Plan was published in 2005. There is a comprehensive programme to monitor the population (Oppel et al., 2014).  Work to control feral livestock in the Centre Hills in order to maintain forest quality has been running since 2009, funded by the U.K.’s Darwin and Overseas Territories Environment Project initiatives, the EU’s BEST initiative, the RSPB, and the Montserrat government (Oppel et al. 2015).

Recent analysis of population data (Oppel et al. 2014) showed no continuing decline in the I. oberi population between 2000 and 2013. Data from continued monitoring in 2014 and 2015 continues to support a stable population (S. Oppel, in litt. 2016). The continued population stability of I. oberi since 2000 means that it no longer qualifies for Critically Endangered status under Criterion B1. However, the species has a very small population (estimated at 476-1,131 individuals) (Oppel et al. 2014) and is present at only two locations where past experience has shown it is extremely vulnerable to stochastic events (Oppel et al. 2014). It is therefore likely to qualify for Vulnerable status under Criteria D1 (number of mature individuals less than 1,000) and D2 (Restricted area of occupancy or number of locations with a plausible future threat that could drive the taxon to CR or EX in a very short time). It is therefore proposed to downlist I. oberi to Vulnerable under Criteria D1 and D2.

Additional information and comments on this proposal are welcomed.



Allcorn, R. I.; Hilton, G. M.; Fenton, C.; Atkinson, P. W.; Bowden, C. G. R.; Gray, G. A. L.; Hulme, M.; 1,5, Madden, J.; Mackley, E. K.; Oppel, S. 2012. Demography and Breeding Ecology of the Critically Endangered Montserrat Oriole. The Condor 114(1): 227-235.

Arendt, W. J.; Gibbons, D. W.; Gray, G. 1999. Status of the volcanically threatened Montserrat Oriole Icterus oberi and other forest birds in Montserrat, West Indies. Bird Conservation International 9: 351-372.

Bowden, C. G. R.; Fenton, C.; Gray, G. A. L.; Mackley, L.; Hilton, G. M.; Atkinson, P. W. 2001. The Monstserrat Oriole: in trouble again. Dodo: Journal of the Jersey Wildlife Preservation Trust 37: 100.

Hilton, G. M.; Atkinson, P. W.; Gray, G. A. L.; Arendt, W. J.; Gibbons, D. W. 2003. Rapid decline of the volcanically threatened Montserrat oriole. Biological Conservation 111: 79-89.

Oppel, S., Cassini, A., Fenton, C., Daley, J. and Gray, G. 2014. Population status and trend of the Critically Endangered Montserrat Oriole. Bird Conservation International 24(2): 252-261.

Oppel, S., Gray, G., Daley, J., Mendes, S., Fenton, C., Galbraith, G., Daniel, S. and Millett, J. 2015. Important Bird Areas – Montserrat. British Birds 108(2): 80-96.

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2 Responses to Archived 2016 topics: Montserrat Oriole (Icterus oberi): downlist to Vulnerable?

  1. Based on the fantastic annual bird monitoring data that the Montserrat Department of Environment has collected over the past years, the Montserrat Oriole has indeed been stable or even increased from 2011 to 2016. The species is vulnerable to deforestation and to volcanic ashfall incidents, but can otherwise maintain a stable population in the existing habitat.

    Based on a population model taking the vagaries of rainfall and volcanic eruptions into account, we have shown that the Montserrat Oriole qualifies as either Vulnerable or Endangered (Oppel, S., Hilton, G.M., Ratcliffe, N., Fenton, C., Daley, J., Gray, G., Vickery, J.A., Gibbons, D., 2014. Assessing population viability while accounting for demographic and environmental uncertainty. Ecology 95, 1809-1818.), and given the more recent trend from 2011-2016 (which is mildly positive), I think that a downlisting to Vulnerable is appropriate at this point in time.

    The species still requires all the Centre Hills forest to be protected, but as long as the forest can be retained, and the volcano does not obliterate any habitat, the Montserrat Oriole can maintain a self-sustaining population.

    I therefore endorse the downlisting to ‘Vulnerable’.

  2. James Westrip (BirdLife) says:

    Based on available information, our preliminary proposal for the 2016 Red List would be to adopt the proposed classifications outlined in the initial forum discussion.

    There is now a period for further comments until the final deadline of 28 October, 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 those in the initial proposal.

    The 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.

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