BirdLife Species factsheet for Spotted Ground-thrush: http://datazone.birdlife.org/species/factsheet/spotted-ground-thrush-geokichla-guttata
The Spotted Ground-thrush, Geokichla guttata (formerly placed in the genus Zoothera) is currently listed as Endangered under criterion C2a(i), on the basis that it has a very small and fragmented population which is declining as a result of habitat loss (BirdLife International 2017). It has a very wide yet scattered distribution, with migratory subspecies from Kenya and Tanzania (subsp. fischeri) as well as South Africa (subsp. guttata) (which have been recorded in Mozambique), a resident subspecies in Malawi (subsp. belcheri) that may also occur in Mozambique, and two other subspecies known from South Sudan and Democratic Republic of Congo (subspp. maxis and lippensi) (see Ndang’ang’a et al. 2005).
As the species is currently listed as Endangered under criterion C2a(i), this requires each subpopulation to contain ≤250 mature individuals, and the global population size should be <2,500 mature individuals. Population size estimates for fisheri (c.200 pairs; Ndang’ang’a et al. 2005, 2008), guttata (<600 mature individuals; Brown 2015) and belcheri (30-40 pairs; Ndang’ang’a et al. 2005) suggest that the population size may fall into the range of 1,000-2,500 mature individuals. However, subpopulation size estimates may be >250 mature individuals and so this species does not qualify as Endangered under criterion C2a(i); instead it qualifies as Vulnerable under the same criterion.
A regional assessment of the South African population (Brown 2015) suggests that rates of decline may be high enough to warrant listing as Endangered under criterion A4c (an ongoing decline of 50-79% over 10 years as a result of a decline in area of occupancy, extent of occurrence and/or habitat quality). However, an analysis of range size changes between Southern African Bird Atlas Projects (SABAP) suggested a range decline of only 28% from 1987-1992 (SABAP1) to 2007-Sept 2014 (SABAP2) (Cooper 2015), which is >10 years in itself. From this data, the species would approach, but not meet the threshold for listing as Vulnerable. Surveys in Kenya in 2003 suggested that very rapid declines may have occurred since the 1980s (Ndang’ang’a et al. 2008), but a global rate of decline over the past 10 years has not been estimated. Therefore, it is unclear as to whether this species would globally meet the threshold for listing as Endangered under criteria A2c+3c+4c (past, future and ongoing decline of 50-79% over 10 years as a result of a decline in area of occupancy, extent of occurrence and/or habitat quality).
We therefore request any further information regarding population trends in this species, and if there is no evidence for declines of >50% then it is likely that this species would not qualify as Endangered under any criterion, but would instead warrant listing as Vulnerable under criterion C2a(i).
BirdLife International 2017. Species factsheet: Geokichla guttata. Downloaded from http://www.birdlife.org on 03/01/2017.
Brown, M. 2015. Spotted Ground Thrush Zoothera guttata. In: Taylor, M. R.; Peacock, F.; Wanless, R. M. (eds.), The 2015 Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland, pp. 171-173. BirdLife South Africa, Johannesburg, South Africa.
Cooper, T. J. G. 2015. The effects of land use changes on the distribution of forest dependent bird species in South Africa. Stellenbosch University.
Ndang’ang’a, P. K.; Mulwa, R.; Jackson, C. 2008. Status of the Endangered Spotted Ground Thrush Zoothera guttata fischeri in coastal Kenyan forests. Scopus 27: 6-9.
Ndang’ang’a, P. K.; Sande, E.; Evans, S.W.; Buckley, P.; Newbery, P.; Hoffmann, D. A.; John, J. 2005. International action plan for Spotted Ground Thrush Zoothera guttata (Threatened Birds of Africa).