Habitat characteristics of potential little owl (Athene noctua) territories in the Bernese and Fribourg Seeland

In the recent decades, populations of little owls have strongly declined throughout Europe. In Switzerland little owls vanished entirely in the late 70ties before populating again the Seeland in 2005. Nowadays, still only a small number of breeding pairs are recorded, and population recovery is slow. Little owls are therefore classified as « endangered » on the Swiss red list of breeding birds. Providing nesting sites and shelter in the form of artificial nest boxes has successfully supported populations in nearby countries. Since 2015 also, the Swiss Ornithological Institute installed more than 200 nest boxes for the little owls in the Seeland. However, the effect of these conservation measures on the little owl was not yet as successful as in surrounding countries.

This study was conducted to quantify the habitat suitability of the area surrounding the nest boxes in the Seeland by comparing them to suitable habitats in southern Germany. In 1 ha plots defined by a nest box in its centre, habitat characteristics were recorded that are crucial for the survival and reproduction of the little owl. This allowed us to investigate similarities and differences between the Swiss Seeland and an existing dataset form high quality areas in Baden-Württemberg, Germany. The majority of the evaluated parameters regarding land cover, land-use and especially resource availability show considerably lower values in the Seeland compared to Baden-Württemberg.

Nevertheless, some parameters such as land-use diversity, the occurrence of grazing as well as the number of roosting sites were higher in the Swiss Seeland compared to Baden-Württemberg. These three parameters likely contribute to the preservation of the existing population in the Seeland and may have a positive effect on its development in the future. However, apart from these parameters, there is an urgent need for ongoing conservation measures improving the conditions for little owls in the Swiss Seeland. The results of this study provide first solutions for further steps towards a successful conservation of little owls in Switzerland.