Effects of land use, nesting-site availability, and the presence of larger raptors on the abundance of Vulnerable lesser kestrels Falco naumanni in Kazakhstan

Abstract

The lesser kestrel Falco naumanni is a cavity-nesting falcon that breeds colonially in steppe-like habitats. Circum-Mediterranean populations declined sharply during the 20th century and the species is categorized as Vulnerable on the IUCN Red List. We investigated the numbers of breeding pairs in Kazakhstan, previously considered to be an important area for the species, where it still inhabits natural steppe and semi-natural grasslands and breeds on cliffs. The availability of cliffs for nesting does not seem to be limiting as most cliffs are unoccupied. However, lesser kestrels tended to breed on small cliffs, where larger predatory raptors are scarcer. Abundance of lesser kestrels was also related to land use. Cliffs in semi-natural grasslands were apparently preferred over those in natural steppe, while those in agricultural landscapes were avoided despite the lower presence there of larger raptors. Large-scale transformation of steppe and grasslands into intensive agriculture might have reduced lesser kestrel numbers, and with the development of new agricultural projects, monitoring and conservation programmes for lesser kestrel populations are urgently required in Kazakhstan.