Abstract

The Montagu’s harrier is a long distance migratory bird. During its migrations it critically depends on stopover sites for fuelling en route. Tracking studies revealed that Northern Africa is a major stopover area for Montagu’s harriers breeding in Western Europe, especially during spring migration. Expeditions in 2010/2011 to Morocco showed that Montagu’s harriers here profit from high numbers of breeding larks. The last decade, the tracked Montagu’s harriers more and more skipped their stopover in Northern Africa. By revisiting Morocco in 2024/2025 for monitoring, it could be confirmed that the original stopover habitat had been degraded by the combined effect of drought and overgrazing by sheep, resulting in reduced prey numbers. Habitat degradation was so severe that prey numbers had not recovered after winter rains. Degradation of stopover sites might have important knock-on effects for survival and reproduction.

About the speaker

Raymond Klaassen is a researcher at the University of Groningen and the Dutch Montagu’s Harrier Foundation. His main research topic is the ecology of farmland birds. In order to conserve farmland birds year-round, he is also interested in migration and wintering ecology. Tracking individual birds with animal-borne transmitters is an important method in his research.