About the Authors

Maris Hindrikson

Affiliation Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia

Peep Männil

Affiliation Estonian Environment Information Centre, Tartu, Estonia

Janis Ozolins

Affiliation State Forest Research Institute “Silava”, Salaspils, Latvia

Andrzej Krzywinski

Affiliation Wildlife Park Kadzidlowo, Ruciane Nida, Poland

Urmas Saarma

Urmas.Saarma@ut.ee

Affiliation Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia

Competing Interests

AK is an employee of Wildlife Park Kadzidlowo who played a role in the data collection and analysis of the manuscript. This does not alter the authors’ adherence to all the PLOS ONE policies on sharing data and materials.

Author Contributions

Conceived and designed the experiments: MH PM JO AK US. Performed the experiments: MH AK. Analyzed the data: MH PM JO AK US. Contributed reagents/materials/analysis tools: MH PM JO AK US. Wrote the paper: MH US.