Monitoring the world population of the Lesser Grey Shrike (Lanius minor) on the non-breeding grounds in southern Africa

Abstract

The world population of the Lesser Grey Shrike funnels in from breeding grounds in Eurasia to an area that is ten times smaller on the non-breeding grounds in the thornbelt of southern Africa, chiefly in the Kalahari basin. The species is abundant in open savanna habitat on the non-breeding grounds, where it is regularly spaced in individual territories and behaves conspicuously as a perch hunter. It has declined considerably during the last 200 years, and the non-breeding grounds offer highly favourable conditions for assessing and monitoring the world population. Extrapolation according to vegetation types of stratified survey data across southern Africa indicates a world population of 6.1 million birds (95% confidence 5.0–7.3 million) during the mid 1990s. However, for sensitive monitoring, the establishment of a standard-effort index is more appropriate than the assessment of the total population.