This discussion was first published as part of the 2013 Red List update, but remains open for comment to enable reassessment in 2015.
Timor Imperial-pigeon Ducula cineracea is restricted to Timor-Leste, West Timor and Wetar, Nusa Tenggara, Indonesia. It is currently listed as Endangered under criterion B1ab(ii,iii,iv,v), on the basis that it occupies a very small range (Extent of Occurrence <5,000 km2), in which it is suffering habitat loss, degradation and fragmentation, such that continuing population declines are inferred. However, in 2008 and 2009 it was recorded from several new locations, thus the species may qualify for downlisting.
Recent observations have revealed a stable population on Gunung Mutis in West Timor. It was recently described as frequent in coffee plantations in the Ermera area of Timor-Leste, although little time has yet been spent surveying at appropriate altitudes for this mostly montane species (Trainor et al. undated). The species was also recorded during surveys of Mt. Mundo Perdido, Timor-Leste, in 2009 (BirdLife International 2009). Also, a recent survey concluded that it is locally abundant on Wetar, with densities of 5-15 birds/ha recorded in gallery forest in Naumatang gorge at 100-200 m (Trainor et al. 2009a). This island appears to support a very high proportion of the global population (Trainor et al. 2009a,b), crudely estimated at 10,000-20,000 birds (Trainor et al. 2009b). If this evidence is confirmed, and the species is known to exist at >10 locations and is not severely fragmented, this species would no longer reach the threshold for Endangered under the range criterion (B). If it has an Extent of Occurrence (EOO) <20,000 km2, occurs at ≤10 locations and is continuing to decline, this species would warrant downlisting to Vulnerable under criterion B1ab(ii,iii,iv,v). However, if it is found at >10 locations, the Timor Imperial-pigeon would qualify as Near Threatened under criterion B1ab(ii,iii,iv,v) of the IUCN Red List on the basis that it approaches the threshold for Vulnerable under criterion B.
The term ‘location’ defines a geographically or ecologically distinct area in which a single threatening event can rapidly affect all individuals of the taxon present. The size of the location depends on the area covered by the threatening event and may include part of one or many subpopulations. Where a taxon is affected by more than one threatening event, location should be defined by considering the most serious plausible threat. (IUCN 2001). For example, where the most serious plausible threat is habitat loss, a location is an area where a single development project can eliminate or severely reduce the population. Where the most serious plausible threat is volcanic eruption, hurricane, tsunami, frequent flood or fire, locations may be defined by the previous or predicted extent of lava flows, storm paths, inundation, fire paths, etc.
Further information on the distribution and population trends of this species is required, and comments on its proposed downlisting are welcome.
Trainor, C. R., Imanuddin, Aldy, F. and Walker, J. S. (2009a) The birds of Wetar, Banda Sea: one of Indonesia’s forgotten islands. Birding Asia 12, 78-93.
Trainor, C. R., Imanuddin., Aldy, F. and Walker, J. S. (2009b) The status and conservation of the Endangered Wetar Ground-dove (Gallicolumba hoedtii) and other wildlife on Wetar Island, Indonesia, 2008: final technical report.
BirdLife International (2009) Endemics thrive on Timor-Leste’s “Lost World” mountain.