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Fieldwork saves foxes

Arctic fox researcher Rasmus Erlandsson tells us about his summer fieldwork

The aim of summer fieldwork is to collect data for research, and to help the County Administration Boards with inventories and conservation measures. It is a bit like putting a jigsaw puzzle together. We know where the fox dens are from previous years, and the County Administration Board often has information about activity seen at different dens in the spring. This means we have a broad picture in place, but to find out the details we have to get out there and visit the dens.

In total, there can be as many as 60-70 dens that need to be visited in each area. Every year is different, so some years it takes much less time than others to do the inventories, it all depends on how many lemmings there are and what the weather is like. If there are lots of lemmings and rodents then there are more litters of cubs, which means more work to do.

Ten-day route up in the mountains above the treeline

Volunteers are put into pairs and each pair is given a route that takes about ten days to cover, this is about the limit to how much food you can carry. At the same time it is important to be out for as long as possible at a time so you don’t waste time by going up and down to get above the tree line. The dens are out in the open landscape with tens of kilometres between them. Sometimes you can use a hiking trail some of the way but the majority of trekking is done in trailless terrain. The distances can be long and everything you need with you has to be carried on your back.

Trekking in pairs means that some equipment can be shared such as the tent and stove which makes the load a little lighter. However, you have to be able to carry some research equipment and that weighs a bit too.

Fieldwork in practice

Volunteers can either get straightforward tasks such as observing and making inventories of the animals the foxes prey on, or observing and marking cubs. Information about their prey is needed to help us understand the different survival conditions the foxes have from year to year. Marking the cubs means that we can follow individual animals throughout their lifetimes, which is otherwise difficult with wild animals. In addition, we collect DNA samples when we mark them which leads to many research questions.

More often than not we get information from the Country Administration Board conservationists about which dens have been active in the spring. And if there has been a lot of activity it is possible that there are cubs in the den, but it is not until we visit the dens that we can confirm this. This is why reports from our observation teams are vital for how we plan the marking work. Marking requires experience as it can be tricky handling wild animals who are not used to humans, and who are afraid of us. So it is important that everyone who works with marking is taught by someone who has experience from previous years, so they can practice and learn.

When we arrive at a den, we have to first find out if it is inhabited or not and then if there are cubs. Initially we observe the den from a distance. If we see don’t see any foxes we look for tracks and signs of activity, such as fresh droppings or diggings. Even if the den is full of cubs, it can take several hours before they are seen, so if it seems that a den is inhabited we set up camp and observe the den for 24 hours. After 24 hours you usually get a good picture of which adult animals are in the den and if there are any cubs and how many there are. If you are unlucky and the weather is bad you may need to stay for longer to get a picture of what is going on in the den. In the worst case you might have to move on even if you are not sure of the situation, and in these cases the den has to be visited again at a later date which can be difficult due to time limitations.

When we visit the dens we also help by filling up any feeding stations in the area with dog food that the local conservationists have put out to help the foxes when food is scarce. We report in the whole time to the conservationists where there are new litters of cubs, how much food has been eaten, and where we have replenished supplies. In this way they can be more efficient with replenishing food and make sure there are feeding stations around newly inhabited dens as well.

Plans often change

Because we often don’t know what things look like in detail before we start getting reports in from our teams in the field, we can’t be sure exactly how the work will be planned. And because the weather and other details can make things difficult we have to be flexible with our planning, and adapt it according to the incoming reports. So it is really important that we constantly reassess plans and that we are able to improvise. To make things even more difficult, cell phone coverage is not the best in the mountains, and in some areas it can be difficult to keep in touch. And as the person who is planning everything is also out in the field it can sometimes be really hard to communicate. But, as a rule, we can send text messages even if we can’t make calls.

Documentation essential even in difficult conditions

All the information that we collect has to be written down and be readable later on so we can enter it into our database. It can be hard work keeping track of all the numbers and papers when you are tired and the weather is bad or the misquotes are thick in the air. But it is essential if we want to get anything out of all the work we are putting into this.

About the author: Rasmus Erlandsson researches the ecology of arctic foxes and is a doctoral student at the Zoology Department of Stockholm University.

• Read more about Rasmus here