About the Authors

Maris Hindrikson, Urmas Saarma
Department of Zoology, Institute of Ecology and Earth Sciences, University of Tartu, Tartu, Estonia

Peep Männil
Estonian Environment Information Centre, Tartu, Estonia

Janis Ozolins
State Forest Research Institute “Silava”, Salaspils, Latvia

Andrzej Krzywinski
Wildlife Park Kadzidlowo, Ruciane Nida, Poland

Corresponding Author

Urmas.Saarma@ut.ee

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.