This discussion was first published as part of the 2016 Red List update. At the time a decision regarding its status was pended, but to enable potential reassessment of this species as part of the 2017 Red List update this post remained open and the date of posting was updated.
BirdLife species factsheet for Mrs Moreau’s Warbler/Winifred’s Warbler: http://www.birdlife.org/datazone/species/factsheet/22714578
This species is found in mountain forests in eastern Tanzania. In the Uluguru and Ukaguru Mountains, it is widespread within a very narrow altitudinal belt (Evans and Anderson 1993, Svendsen and Hansen 1995), although territory density is variable (Svendsen and Hansen 1995), while in the Udzungwas there is a single record from Mwanihana Forest, where it has not been recorded since the late 1980s, despite much searching (J. Fjeldså in litt. 2007, 2012, L. Hansen in litt. 2007). In Ukwiva Forest Reserve (100 km2) in the Rubeho Mountains, between the Udzungwas and Ukagurus, the species was found to be fairly common but probably localised and patchy in occurrence (J. Fjeldså in litt. 2007). This Rubeho population, rubehoensis, was recently described as a separate species (Rubeho Warbler: Bowie et al. 2009); however, we consider rubehoensis as a subspecies of winifredae.
Its population size had previously been estimated to fall into the band of 10,000-19,999 individuals (equating to roughly 6,000-15,000 mature individuals). However, a more recent estimate of the population was of 1,500 individuals and possibly as low as 500 (L. Hansen in litt. 2016), which would equate to roughly 330-1,000 mature individuals.
It is currently classed as Vulnerable due to it having a small range which is severely fragmented and declining in extent and quality. However, with this updated population estimate it would also qualify as Vulnerable under criterion C2a(i), and may qualify as Endangered under this criterion if the number of mature individuals in each subpopulation are ≤250. We therefore welcome any information regarding this new population estimate, and any information regarding the population sizes of isolated subpopulations of this species to see whether this species warrants uplisting.
Bowie, R. C. K.; FjeldsÃ¥, J.; Kiure, J. 2009. Multilocus molecular DNA variation in Winifred’s Warbler Sceptomycter winifredae suggests cryptic speciation and the existence of a threatened species in the Rubeho-Ukaguru Mountains of Tanzania. Ibis 151: 709-719
Evans, T. D.; Anderson, G. Q. A. 1993. Results of an ornithological survey in the Ukaguru and East Usambara mountains, Tanzania. Scopus 17: 40-47
Svendsen, J. O.; Hansen, L. A. 1995. Report on the Uluguru Biodiversity Survey 1993. Royal Society for the Protection of Birds/Tanzania Forestry Research Institute/Centre for Tropical Biodiversity, Sandy, U.K.