Languy (2019, Birds of Cameroon) maps the confirmed observations of this species, with 5 confirmed sites (dots on map)
Criterion B. The EOO based on Languy is smaller than the range you present in your map, although I do not know if this aligns with the 51,700 km2 that is used to quantify the population in the species review. Might it approach 20,000 km2? The AOO based on Languy would seem to be smaller than 2,000 km2 and possibly even 500 km2. As it is known from few sites (5 dots) as well as declining habitat, it might therefore be VU or even EN based on this criterion.
Criterion D. If it is known from 5 sites or fewer, then it may meet this criterion.
I fully agree with the comments of Hugo. This species is known only from few sites (confirmed by Marc Languy in Birds of Cameroon, 2019) and has a declining habitat. You should maintain it as EN based on these criteria.
Many thanks to everyone who has contributed to this discussion. We greatly appreciate the time and effort invested by so many people in commenting. The window for consultation is now closed. We will analyse and interpret the new information and post a preliminary decision on this species’s Red List status on this page in early July.
Thank you once again,
BirdLife Red List Team
Based on available information, our preliminary proposal for the 2021 Red List would be to retain Bates’s Weaver as Endangered under Criterion C2a(i).
Based on this species’s apparent rarity, and the scarcity of records, taking the lower quartiles of density estimates of a forest-dwelling congener, the Southern Masked-weaver Ploceus velatus, of 0.59-2 individuals/sqkm (BirdLife Population Density Spreadsheet; Vernon 1985; Dean 1995), and assuming it inhabits 5% of the forest within its range (51,700 sqkm [Global Forest Watch 2021]), the population may fall in the band 1,525-5,170 individuals. This is roughly equivalent to 1,016-3,447 mature individuals rounded here to 1,000-3,500 mature individuals. On further consideration of the evidence, this can be considered an estimate. Furthermore, if it is known from 5 different sites, this species may have multiple subpopulations, so it is plausible that there may be <1,000 mature individuals in the largest subpopulation.
There is now a period for further comments until the final deadline in late July, after which the recommended categorisations will be put forward to IUCN.
The final 2021 Red List categories will be published on the BirdLife and IUCN websites in December 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Dean, W. R. J. (1995) Where birds are rare or fill the air: the protection of the endemic and the nomadic avifaunas of the Karoo. PhD thesis, Zoology Dept, University of Cape Town.
Vernon, C. J. (1985) Bird populations in two woodlands near Lake Kyle, Zimbabwe. Honeyguide 31: 148-161.
Recommended categorisation to be put forward to IUCN
The final categorisation for this species has not changed. Bates’s Weaver is recommended to be listed as Endangered under Criterion C2a(i).
Many thanks for everyone who contributed to the 2021 GTB Forum process. The final 2021 Red List categories will be published on the BirdLife and IUCN websites in December 2021, following further checking of information relevant to the assessments by both BirdLife and IUCN.
Comments are closed.
Contact the BirdLife Red List Team under redlistteam [at] birdlife [dot] org.