Justification of Red List Category
This species has a very large range, and hence does not approach the thresholds for Vulnerable under the range size criterion (Extent of Occurrence <20,000 km2 combined with a declining or fluctuating range size, habitat extent/quality, or population size and a small number of locations or severe fragmentation). The population size has not been accurately quantified, but it is not believed to approach the thresholds for Vulnerable under the population size criterion (<10,000 mature individuals with a continuing decline estimated to be >10% in ten years or three generations, or with a specified population structure). The population trend appears to be stable, and hence the species does not approach the thresholds for Vulnerable under the population trend criterion (>30% decline over ten years or three generations). Therefore, the species is now listed as Least Concern.
The population size of this species has not been quantified, but it is described as locally common. From sightings of 16 individuals over 3 sites, a potential density of 0.61 individuals/ha was estimated (Magin 2013, Kipkoech et al. unpubl.) for the northern part of its range (north of Marsabit). Githuru et al. (unpubl.) covered the southern part of its range (between Isiolo and Garba Tula) and found very similar population density estimates (0.7 ± 0.14 individuals/ha). Githuru et al. highlight that they failed to find the species in some areas of suitable habitat; thus, these values may not be representative for the whole range and the density estimates should only be used a rough gauge rather than accurately estimating the global population size. Doing this, and assuming only a proportion of its range is occupied gives a population size estimate of >200,000 mature individuals. This could still be a large overestimate, but it does highlight that the overall population size is likely above 10,000 mature individuals.
The species's habitat is potentially threatened by livestock grazing and encroachment, but it is unclear whether this is actually affecting the species, and at the moment there is no evidence that they having an impact (Githiru et al. unpubl., Kipkoech et al. unpubl.). As such, the population trend is considered to be stable.
Mirafra williamsi is endemic to northern Kenya, where it is found in two disjunct populations, one in the Didi Galgalla Desert (north of Marsabit) and the second between Isiolo and Garba Tula (Keith et al. 1992). The species was not discovered until 1955 and its ecology, distribution, threats and population parameters remain little known (Lewis and Pomeroy 1989). The species is easiest to locate at dawn after the rains, when males engage in very long song flights around their territories (Keith et al. 1992). A survey was carried out in 2011, which located 16 individuals over 3 sites (Magin 2013), and further surveys elsewhere have found a similar population density to this (Githuru et al. unpubl.).
The species was not discovered until 1955 and its ecology, distribution, threats and population parameters remain little known (Lewis and Pomeroy 1989). The Marsabit population inhabits scattered short-grass areas with low shrubs growing on rocky desert plains and red lava soils, while the Isiolo population inhabits uniform stands of low Barleria shrubs on rocky lava desert (Zimmerman et al. 1996) at 600-1,350 m (Lewis and Pomeroy 1989). It feeds on insects and seeds, but nothing is known of its breeding ecology (Keith et al. 1992).
This species might be susceptible to encroachment and heavy grazing by cattle, goats and camels (Magin 2013), but it is not certain that these potential threats are actually impacting the species (Githiru et al. unpubl., Kipkoech et al. unpubl.).
Conservation Actions Underway
None is known.
14cm. Heavy billed small lark with fairly plain upperparts and a rufous-brown appearance. Pale supercilium and neck-collar contrast with dark ear coverts and crown. Similar spp. White-tailed Lark M. albicauda, Friedmann's Lark M. pulpa and Singing Lark M. cantillans are less rufous, while Foxy Lark Calendulauda alopex is more rufous than M. williamsi and also has a slighter bill. Voice Thin, scratchy notes with a repeated sirreet at the end of each series.
Text account compilers
Evans, M., Butchart, S., Bird, J., Robertson, P., Starkey, M., Symes, A., Westrip, J.
Finch, B., Donald, P.
BirdLife International (2019) Species factsheet: Mirafra williamsi. Downloaded from http://www.birdlife.org on 18/10/2019. Recommended citation for factsheets for more than one species: BirdLife International (2019) IUCN Red List for birds. Downloaded from http://www.birdlife.org on 18/10/2019.