The secretive live of mice and voles!

    Can monitoring of small mammal traces reveal activity patterns in an agricultural landscape?

    Small mammals (especially members of the suborder Myomorpha/mouse relatives) are an important food source for many avian raptor and owl species in the agricultural landscape. The temporal and spatial fluctuations in small mammal populations also have a strong influence on the distribution and size of home ranges of their predators. Therefore, the characterization of small mammal abundance and activity patterns is important to infer habitat quality for predatory birds. However, this task is challenging due to the heterogeneity of small mammal populations at several scales: Small mammal populations not only show cyclic perennial fluctuations, but also vary over the course of the year. Moreover, they are not homogenously distributed over the landscape. Rather, population densities and species composition vary with the type of crop, the intensity of management, and with structures within the landscape. However, so far most studies that investigated small mammal distribution and abundance in an agricultural landscape used data from a restricted spatial and temporal resolution. This also restricts the predictions that can be made about the potential influence of small mammals on predatory birds. In the proposed master project, the student is going to make use of small mammal monitoring data collected over 5 years with the aim to quantify food availability for barn owls. We counted traces of voles and mice in bimonthly intervals within four geographical regions in six different habitats in western Switzerland. These data were collected using two different techniques (track plates and transect counts of traces), and capture a broad spectrum of small mammal species and activities throughout the year. First analyses show that small mammal activity peaks differently in different habitats, and we now suggest to further analyse the data to obtain additional insight into the activity and distribution of small mammals in a structured landscape and how they predict prey availability for raptors across seasons. The main questions deal with the importance of the different habitats for small mammal activity throughout the annual cycle and how landscape composition affect small mammal distribution and cycles.

    Requirements

    Interest in applied ecology and in large data sets, good skills in data analysis, background in spatial analysis, previous experience in working with R and GAMs, independent and responsible personality. This project can start any time, but preferably before July 2021. Potentially a small part will consist of field work (validating traces on track plates by use of cameras).

    Contact

    Swiss Ornithological Institute
    Dr. Stephanie Michler
    6204 Sempach
    email: stephanie.michler@vogelwarte.ch
    Tel: 041 462 97 68