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 Rudd’s Lark: http://www.birdlife.org/datazone/species/factsheet/22717153
Heteromirafra ruddi is endemic to east South Africa, and is currently listed as Vulnerable on the basis that it has a small, declining population, within which all subpopulations are very small, and that declines are predicted to become rapid over the next three generations (11 years).
Records are patchily spread over a large area, with the core of its restricted range centred on south-east Mpumalanga, and north-west KwaZulu-Natal. Small, isolated populations are also found further north in Mpumalanga, in KwaZulu-Natal and south into the Eastern Cape. The population size is estimated at <10,000 individuals, but may be as low as 2,500 mature individuals (Taylor et al. 2015), and no recent definite records from its former stronghold (D. Maphisa in litt. 2016). It has a proposed Area of Occupancy of 3,435km2, and may have undergone a decline of >50% in the past 3 generations as well as a continuing decline in the quality and extent of habitat (Taylor et al. 2015). Thus, in the 2015 Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland (Taylor, Peacock and Wanless 2015) this species is listed as Endangered under criteria A2c+3c+4c; B2ab(i,ii,iii,iv,v); C1.
Other analyses using Southern African Bird Atlas Project data have suggested a slightly lower decline in range (40% decline in range, 14% decline in core range; Lee et al. in press), which would mean the species would not meet the threshold for classification as Endangered under criterion A.
We therefore request any extra information about the population size and possible trends to ascertain whether this species qualifies as Endangered under criteria A2+3+4 (observed, estimated, inferred or suspected population reduction in the past or projected into the future of ≥50% where the causes have not ceased or are not understood); or C1 (population <2,500 individuals and observed, estimated or projected continuing decline of 20% in 5 years or 2 generations).
Lee, A.; Barnard, P.; Altwegg, R. (in press) Estimating conservation metrics from atlas data: the case of southern African endemic birds. Bird Conservation International.
Taylor, M. R.; Peacock, F.; Wanless, R. M. 2015. The 2015 Eskom Red Data Book of Birds of South Africa, Lesotho and Swaziland. BirdLife South Africa, Johannesburg.