Keeping up with the Castors

Keeping up with the Castors

Releasing any animal into the wild can be quite a task, and there’s a lot to think about. From barn owls to badgers, I’ve seen many of our native species back to the wild. Though the end result is often very rewarding, there are plenty of long days and sleepless nights before, and after, the final release. But if our well-known species are tricky, imagine the challenges to overcome when bringing the beaver back to Britain after centuries of absence?

Who? What? Where?

As with any species, finding a suitable site is vital and the ecology of the beaver must be well understood. All of their natural needs must be met, and the scale of the project will influence the size of the site. For enclosed studies, you need to install some beaver-proof fencing, whilst still allowing access for monitoring. 

In a wild reintroduction, the wider landscape has to be considered, taking into account any nearby roads, the potential for dispersal, and it’s always easier if local landowners are on board too. The first wild release in Scotland, the Scottish Beaver Trial, took place on the Knapdale Estate which features short river systems and is contained by a natural ridge to the east and the sea to the west, preventing the beavers from dispersing too widely during this trial reintroduction. 

But, where do you get the beavers from? The first beavers released in the UK, at the Ham Fen Beaver Project in Kent, were from Norway. In fact, Norwegian beavers have been the source population for many beaver reintroductions in Britain and were selected for a number of reasons. We know from studies comparing Norwegian beavers with the remains of those that lived in Britain that they are genetically very similar so would hopefully adapt to life in the UK well. 

It’s important to consider the social ecology of the species and how that might affect their success in the wild. Orphaned badgers, for example, are reared and released in small social groups, in the hopes that an already bonded group will settle and stick around. Some projects have seen families of beavers released together for the same reason. Others have released individuals of a few years old, the age when they’d naturally disperse, in the hope that they will form a breeding pair.

Once the desired individuals have been identified within the source population, they need to be caught. But just how do you go about catching a large, illusive semi-aquatic rodent? There are a few methods used, either using a live trap or by wrangling the beaver into a boat with a hand-held net. Extra care has to be taken if a family group is being moved to ensure that no members of the family are left behind. 

Once caught, their journey to the UK begins. The beavers usually travel by air, and must spend some time in quarantine to eliminate any disease risk. In the UK, many beavers have spent their quarantine period under the care of Derek Gow on his farm in Devon. 

Time to release the beaver

Wildlife releases are usually categorised as either hard or soft. A hard release involves just letting the animal go into its environment. This is fine for adult animals who already have a territory established and know how to survive in that area.

A soft release is a more gradual process, allowing the animal to adjust to its new surroundings and often involves some kind of temporary enclosure and some support feeding. With birds we construct a temporary aviary at the release site and allow them to build their flight muscles in their new surroundings before we open the door. With badgers, we often build an artificial sett and fence off a foraging area around it while they settle in. This is often easier said than done, and I’m familiar with animals leaving the release pen a bit early of their own accord. During the Scottish Beaver Trial, each beaver family was released straight into an artificial lodge provided on the bank of the loch. Rather than take some time to settle in and then leave gradually, the beavers broke out of these lodges within the first day, giving themselves a slightly harder release than planned! Though they may not actually be living entirely wild, those projects where beavers were released into enclosed areas could be regarded as a soft introduction to life in the UK.

Keeping up with the Castors 

Monitoring the beavers post-release is crucial to gauge the success of their reintroduction. It’s not enough to just let an animal go. We need to see if they survive and even breed. If they don’t, there can be important lessons to be learned about the whole process. There are several ways to monitor animals in the wild and some species are easier than others. Beavers have nice flat tails which can carry a radio tag, whilst camera traps can capture some great images to see how they’re doing and show the public what enigmatic animals they are. Of course, there’s no substitute for field signs and tracking the animals in person. Like badgers with their sizeable earthworks and distinctive paths, beavers quickly make their mark on the landscape and these ecosystem engineers leave plenty of conspicuous calling cards.

Believe in the beavers

So a beaver reintroduction is clearly a big task, but there are plenty of very willing and very capable people who have done just that, and the positive effects of their work are already evident. Personally, I can only hope that one day I might be involved with one of these exciting projects. Even after a 400-year absence, I’m sure there are plenty more viable sites for beavers across the UK, and I can’t wait to see them there.*