Habitat selection and range use of little owls in relation to habitat patterns at three spatial scales

Abstract

Understanding the rules of habitat selection and the individual behavioural routines in the home-range is crucial for developing evidence-based conservation action. We investigated habitat selection and range use of adult little owls Athene noctua in relation to landscape configuration, habitat structure and resource distribution. We determined the preference of habitat structures by VHF-telemetry. Large-and fine-scale distribution patterns of volesthe main prey during the breeding season were assessed by transect counts of signs of vole presence. An experiment using artificial perches was carried out to determine the fine-scale adjustment of the owls' range use in relation to prey abundance and vegetation height. Habitat selection and resource exploitation by little owls were structured at all spatial levels: (1) at the landscape scale, orchards were highly preferred over other areas. This accords with the patchy large-scale occurrence of voles, which were absent in cropland, but abundant in orchards and grassland; (2) within home-ranges, the spatial distribution of voles was highly inhomogeneous and structures with high prey abundance were used over-proportionally; (3) at the scale of foraging sites, little owls preferred patches with low vegetation over those with high prey abundance, establishing that prey availability is the crux. The results suggest that all levels of habitat selection and range use were related to farming practices and affected by current cultivation. Conservation measures should focus on the conservation and restoration of orchards on the landscape level and habitat management measures should focus on grasslandsthe main food providersby creating a mosaic of patches with short grass and tall grass. Together with other habitat structures providing food resources such as field edges, wildflower areas and structures facilitating access to prey, the quality of habitat patches in terms of food availability may be highly improved.

Rodents, not birds, dominate predation-related ecosystem services and disservices in vertebrate communities of agricultural landscapes

“…Westerman et al 2003a ; Baraibar et al 2012 ; Fischer et al 2017 ). Rodent densities in crop fields are often relatively low (Aschwanden et al 2007 ; Fischer and Schröder 2014 ; Apolloni et al 2017 ) and a previous study found low predation rates by rodents (e.g. Baraibar et al 2012 ).…”

Little Owl’s (Athene noctua) vertebrate food composition during breeding season with high frog dominance in grasslands

“…As it was already previously known, it hunts for a wide variety of prey due to its large distribution area and various hunting techniques (Mikkola 1983, Cramp 1985, Angelici et al 1997, Van Nieuwenhuyse et al 2008. This is well reflected in the prey composition of Little Owls of different geographical regions (Shehab et al 2004, Charter et al 2006, Kayahan & Tabur 2016, and in different habitats within the same geographical region (Van Nieuwenhuyse et al 2008, Apolloni et al 2018. The role of small mammals in the Southern European region is generally less important; however, vertebrates can be dominant in some Mediterranean regions (Goutner & Alivi zatos 2003); in Central Europe the proportion of small mammals is usually high (Zerunian et al 1982, Mánez 1983, Schönn et al 1991, Ille 1992, Genot & Van Nieuwenhuyse 2002, Gorzel & Grzywaczewski 2003, Tomé et al 2008, and the present study).…”

“…This negative tendency can be observed also in the case of farmland bird species in Hungary (Szép & Nagy 2006, Báldi & Batáry 2011, Szép et al 2012. Nevertheless, in addition to nesting-site availability, the trend of a given Little Owl population is closely related to the feeding possibilities and food availability (Génot & Van Nieuwenhuyse 2002, Thorup et al 2010, Apolloni et al 2018. In general, the effects of agricultural intensification may result in a decrease in the abundance of arthropods and small mammals (Morris 2000), which are the primary food sources for the Little Owl (Van Nieuwenhuyse et al 2008).…”

“…In general, the effects of agricultural intensification may result in a decrease in the abundance of arthropods and small mammals (Morris 2000), which are the primary food sources for the Little Owl (Van Nieuwenhuyse et al 2008). Furthermore, habitat transformations in agricultural areas may further reduce the availability of food to the owls (Apolloni et al 2018). The Little Owl has various haunting techniques.…”

Political borders impact associations between habitat suitability predictions and resource availability

“…S1). The study areas are characterized by a mosaic of intensively cultivated agricultural fields, sown leys, permanent meadows, vineyards and orchards (Grüebler et al 2014 ; Apolloni et al 2018 ). Whereas Germany and Switzerland were broadly inhabited by little owls in the middle of the last century, populations recently declined as they did across many parts of Europe with only a few breeding pairs left in Switzerland (Schaub et al 2006 ; Thorup et al 2010 ; Habel et al 2015 ).…”