Small rodent communities Join the research on the mysterious vole cycles!

Hands-on experience with live animal research. Internship adapted for each participant. At the Inland Norway University of Applied Sciences.

One of the study areas is a ditch habitat and very close to campus Evenstad.


Small rodents, such as bank voles, field voles and lemmings have some years massive population densities. Being herbivores, they may during such high densities greatly affect plants –this impact have even been observed by satellites in space! Other years, the populations are so small they're seemingly extinct. In the northern parts of Europe, this phenomenon happens in such a regular fashion every 3-4 years, that we call it populations cycles. But why it is so regularly? That’s one of longest living mysterious in ecology, but we are getting closer!

Harry P. Andreassen (1962-2019) was a professor in population ecology and dean at Evenstad. He was a role-model with his high quality and joy for research, and his mentorship in a multitude of international and student projects. Photo credit: Petter Glorvigen.

Evenstad have long traditions for high quality research (e.g. published in the prestigious journals like Nature and Ecology) on small rodent populations using experiments, enclosures and on natural populations in the field. For the last couple of years, we have also expanded our studies to include live trapping during winter. At the moment, much of our focus involve food and predator interactions, climate and parasite effects.

Charles Elton in 1926 (photo from the British Ecological Society). Even after a century of research, the drivers of vole population cycles are still a mystery.

The internship

The main tasks will be trapping live small rodents to monitor this community over time. You’ll meet bank voles, tundra voles, yellow-necked mouse, common shrew and perhaps wood mouse, field vole, taiga shrew, pygmy shrew and... if you're lucky also a least weasel in the traps. Your focus will be on bank voles and tundra voles. When trapped and marked, we can perform various demographic measurements like determine species, sex, weight, parasite load, do behavioural measures and more before we release them, depending on what projects that are active and your own interests.

A normal trapping week is only 4 days (3 evenings and 3 mornings) and we have two such “weeks” per month. The days when trapping often become long and you can expect to be tired afterwards, but all other days have a more comfortable time schedule. Besides from trapping, we try to adapt each internship to the interest and needs of the individual applicant. This might be to increase the focus on e.g. the plant community in this habitat or the climate's effects on the populations. Some work in the laboratory may also be possible, setting up smaller experiments, as well as analysing data.

Part of our study area is in a spruce-dominated forest

When to apply: Our main data collection, the trapping data, is part of a growing long-term data series. To continue expanding this time-series we need 1-2 motivated field workers each month, all year. Since we have activities all year we welcome you to apply for internships that start any time of the year, but encourage stays that span over some time. Please contact Magne Neby at magne.neby (at) inn.no for any questions.

Here, two of our internship students is identifying the sex and age of a live bank vole.

Challenges and what to bring. At Evenstad we are in the midst of the boreal/taiga biome, so all sorts of weather may occur, from 30 degrees hot, to -30 cold. Deep snow, floods and impressive amounts of mosquitos...BUT, mostly its actually very nice working conditions! However, it's important that you bring clothing appropriate for the climate and season, because no weather will keep us from going out. Please ask us for advice if unfamiliar with Scandinavian outdoor conditions to avoid surprises.

Besides joining our research group and working with voles, you will also have the opportunity to join other active field research projects at Evenstad.

Bank vole

Thesis? Sometimes students want to use this experience as part of their bachelor or master thesis. You are welcome to do this and you will be able to use the data that you have collected and get access to our long-time series, but remember to talk with us about this when applying for the internship. Since you will not be enrolled in a degree at Evenstad we can’t offer you supervision on your thesis if this is not agreed before arriving.

We hope to hear from you! Please contact Magne Neby at magne.neby (at) inn.no for any questions.

Here one of our Master students is finishing measurements in the forest.

A special thanks to all contributors:


Laget med bilder av MrsBrown - "mouse vole rodent" • jggrz - "mouse rodent leaves"