Population status of the range-restricted Red Lark Calendulauda burra in a conservation area stronghold

Abstract

Many desert birds are vulnerable to anthropogenic global warming and landscape transformation, particularly in the case of range-restricted species. We quantified suitable habitat and the current population of Red Larks Calendulauda burra (family Alaudidae), a range-restricted southern African species, in a conservation area thought to be one of the species’ strongholds — the Black Mountain Mine Conservation Area (BMMCA) in the Northern Cape, South Africa. We modelled habitat suitability and estimated home range sizes using telemetry data and kernel density estimates. Home range sizes did not differ between males (42.4 ± 28.3 ha; n = 5) and females (41.9 ± 31.3 ha; n = 5). Transect data and home range density models indicated densities of 0.086–0.127 individuals·ha-1 for adults in suitable habitat. An estimated 33.2% (30.2 km²) of the BMMCA is suitable habitat for Red Larks, suggesting a population of 232–382 individuals. This population estimate is equivalent to <50% of the population estimated for the BMMCA in 1989. Our findings here, combined with a recent analysis showing that much of the species’ range will become thermally unsuitable for its persistence by the end of the 21st century, suggest that urgent conservation action is needed to ensure the Red Lark’s future in coming decades.