From individual movement patterns to population processes

This project aims at investigating the key ecological factors that limit the individual performance and population development of little owls throughout the year. It incorporates their habitat requirements and how changes in habitat characteristics affect body condition, breeding performance and survival. The relationship between these factors and individual range use and dispersal represents a main focus of the study. Enhancing our knowledge about key ecological factors will allow identifying the critical ‘bottlenecks’ in the life history of the little owl.

The main part of the study was conducted in a large population of little owls in southern Germany. Here, adults and juvenile birds were ringed and equipped with radio-transmitters. Their movements were recorded during four years. Food supplementation and cross-fostering experiments were conducted and detailed data on habitat, individual traits, reproductive performance and survival were collected. The analysis of this data sheds light on the habitat requirements, demography, and behaviour of little owls. These insights are now used to understand the limitations of a small Swiss population, where comparable data are collected since 2015.

The little owl is one of 50 priority species of the Swiss Species Recovery Programme. It is a typical species of agricultural landscapes with high biodiversity and can serve as an indicator for bird-friendly agricultural management. The investigation of key ecological aspects provides crucial information to improve conservation measures for little owls in Switzerland and abroad. Understanding range use and dispersal of little owls allows developing measures to facilitate the reconnection of fragmented populations and recolonization of potential habitats.

Meadows provide higher food availability than arable fields and the proportion of meadows around the nests increases reproductive performance. In turn, high food availability in the breeding territory result in increased nestling, post-fledging, and adult survival. Juveniles from high-quality habitats also leave the parental territory later than those from low-quality habitats. Areas close to forests are strongly avoided. Survival of both, adults and dispersing juveniles is reduced in winter and tree cavities represent an important resource for roosting during wintertime.

• Max Planck Institute of Animal Behavior
• Forschungsgemeinschaft zur Erhaltung einheimischer Eulen e.V.
• BirdLife Schweiz
• Berner Vogelschutz BVS
• Berner Ala
• IBA Arbeitsgruppe 004
• Büro für Landschaftspflege und Faunistik
• Quadropoda

• Swiss National Science Foundation SNSF
• Hirschmann Stiftung
• Karl Mayer Stiftung
• Ernst Göhner Stiftung
• Stiftung Accentus
• Parrotia-Stiftung