Foraging strategies of an aerial-hawking insectivore, the common noctule bat Nyctalus noctula

• Main Author: Röleke, Manuel
• Other Authors: male, Voigt, Christian C, Tietjen, Britta
• Format: Doctoral or Postdoctoral Thesis
• Language: English
• Published: 2019
• Subjects: Foraging ecology; Movement ecology; Chiroptera; GPS; Playback; Coexistence; ddc:577; Nyctalus noctula
• Online Access: https://refubium.fu-berlin.de/handle/fub188/24921; https://doi.org/10.17169/refubium-2681; https://nbn-resolving.org/urn:nbn:de:kobv:188-refubium-24921-9

Movement is a key signature of life. Yet, the integration of movement ecology and biodiversity concepts was only recently formalize. In this framework, an individual’s movement path and the underlying drivers are used to explain interactions between individuals and eventually species coexistence. Interactions influence the individual’s environment including species assemblage, and thereby feed back on the individual’s movement path. Foraging represents one of the most common movements of many animals, and thus has been of interest for ecologists ever since. Yet, classical foraging ecology predominantly focused on optimality models to explain the behaviour of single foragers, but rarely took into account the interactions between moving individuals. The overarching question of the three studies in this thesis thus was “How can different foraging strategies support coexistence?”. Being highly mobile and showing a large niche overlap with several other species, the insectivorous Common noctule bat Nyctalus noctula (Schreber, 1774) is an ideal model species to study intra- and interspecific interactions during foraging movements. I therefore investigated movement behaviour and space use of N. noctula during aerial foraging, and evaluated the potential role of different foraging strategies for the coexistence of competing bat species in the light of different competitor densities and prey distributions. In chapter one, I asked whether foraging N. noctula adjust their space use to abiotic factors (i.e. moonlight) which might be linked to prey distribution. I used GPS (global positioning system) loggers to investigate the habitat use of nine N. noctula during high and low moonlight intensities. During moonlit nights, N. noctula hunted preferentially over open fields, whereas they avoided open fields in dark nights. I suppose that foraging activity followed changes in insect activity triggered by the lunar cycle. The results suggest that N. noctula might be able to predict cyclic changes in prey distribution. The ...