Beavers: frequently asked questions

Your beaver questions answered

Why we want to see beavers return to Shropshire

Eurasian beavers (Castor fiber) are a species of rodent that is native to England, but was hunted to extinction by the 16th century for their fur and meat. They were a celebrated animal in many parts of the British Isles and their name was even used in the names of towns and villages.

The Shropshire project aims to trial release of 2 beavers within an enclosed site within Shrewsbury's Old River Bed nature reserve to assess the impact of these industrious mammals on an existing wetland site. The beavers will be monitored comprehensively by ecologists during the trial and the fence that will be installed to protect them has been specially designed to keep them on the site.

Below, we answer some of the big questions that might be on your minds regarding the release of beavers.

What do beavers eat?

  • Beavers coppice trees to create dams. Many of the trees beavers cut for damming, are species like willow which will grow and re-root where they are ‘planted’ by the beaver. The wet habitats they can create also hold carbon that would otherwise release into the atmosphere as CO2
  • In summer, beavers graze mostly on riverside plants and grasses. In winter they feed mostly on tree bark and shoots, but never completely destroy woodland as they depend on trees to survive
  • Beavers like to eat willow and aspen trees, and to a lesser extent, alder. They will take fruit trees (particularly apple) and poplar trees if these are close to watercourses
  • Beavers tend not to move far from fresh water, so impacts are often very close to the riverbank, generally within 30m
  • Most native trees will naturally re-sprout when cut (coppicing). The willows growing on the Old River Bed would eventually take over the reserve if left unmanaged
  • Special trees can easily be protected from beaver activity

Do beavers cause flooding?

  • The Old River Bed nature reserve is an enclosed catchment basin and is an existing wetland site that is protected for the wetland plants found there
  • Beavers can make rivers less prone to flash floods, reducing flooding by holding water in ‘the right place’ in river headwaters, and enabling the slower release of water in drier periods
  • A project with the University of Exeter in the River Otter has studied the impacts of beavers on water flows and hydrology in great detail. The preliminary results are remarkable and show that beavers tend to decrease flooding overall as their activity slows the flow rate of flowing water
  • It is important to differentiate between the storage of water by beavers in river headwaters, and the impact of beavers on low lying land. In some places, culverts and drainage systems, some of which are critical to reducing flood risk, need to be kept clear of beaver debris
  • In order to create habitat for themselves, and to store water upstream, beavers need to temporarily and seasonally flood areas of land to create beaver ponds. This can be managed so that they do this in areas where flooding is wanted

Do beavers eat fish?

  • Beavers are entirely vegetarian (herbivorous) and don’t eat fish. Their presence is generally very positive for most fish species
  • The natural wetland habitats that beavers create often help to increase natural fish populations
  • Concern is expressed by some, about the ability of salmon and sea trout to get over dams. The science suggests that long term benefits generally outweigh any localised short term impacts  
  • Natural woody material is a natural part of river systems and fish have migrated through these natural obstructions for millennia
  • Man-made obstructions to fish passage have a far greater impact on migrating fish populations
  • The dams created by beavers act as water filters and can clean watercourses, which benefits fish and many other species of wildlife

How quickly do beavers breed?

  • Beavers breed once a year, and have an average of 3 young (called "kits")but only breed at 2-3 years old
  • Beaver kits are vulnerable to predation by foxes, birds of prey and maybe otters – so not all kits survive
  • Once territories are established, population numbers only rise slowly
  • Beavers live in strict family groups, with only the dominant pair breeding
  • At high densities, territorial behaviour regulates their populations
  • Some beaver youngsters may choose to stay at home and help their parents rather than breed themselves when populations are at higher densities
  • Beaver numbers and the resources available to them will be monitored throughout the project to ensure animal welfare
  • As the Old River Bed is an enclosed site and the release area will be protected with a heavy-duty fence, if the first beavers do breed, it will be impossible for them to escape into the wider area

Why are beavers important?

  • Beavers are a “keystone species” which play an important role in restoring British wetland ecosystems. They naturally create resilient networks of prime wetland habitat, which in turn produces natural capital benefits such as flood relief and benefit a wide range of species including amphibians, fish and bats
  • Beavers naturally engineer watercourses to create deeper water so they can escape from predators and explore their territories. Where there is no existing deep water, they will create pools using small dams
  • There are habitats specifically created by beavers that are lacking in Britain, including beaver meadows, beaver dams and flooded wet woodland
  • Beavers can play a key role in increasing woodland, wetland, open water and riparian vegetation and wildlife diversity
  • Wetlands are some of the most important habitats for supporting wildlife (over half of the UK's wildlife depends on them) so their restoration is crucial to the restoration of a healthy living landscape

Where do beavers live?

Although beavers build dams, they don't actually live in them. They also build a lodge, which appears as a large pile of loose logs from the outside. A lodge has an insulated inner compartment, often with an entrance through a tunnel directly into the water and can be as big as 6 metres across!

Will I be able to go to see the beavers?

Beavers are usually hard to spot as they come out at dusk and are usually safely tucked away in their lodges by the time the sun rises. The Old River Bed is a wetland site and the beaver enclosure will be difficult to access due to the boggy conditions. However, we do plan to organise guided visits to the site once the beavers are settled in and when we are confident that there are reliable spots for beaver viewing. Any planned supervised visits will be posted on our events pages and existing members of Shropshire Wildlife Trust will be be invited to VIP visits in the future. Another good reason to become a member today!

Why do the trees need to be managed?

We all know that trees play a vital role in absorbing CO2 from the atmosphere and help to combat climate change, but only when they grow in the right places. Wetlands actually store more CO2 than woodlands, but if left unmanaged, the willow trees at the Old River Bed would soon outgrow other plants and would dry the site out and impact it's ability to store carbon. Beavers will help to control the growth of willows through natural coppicing, which means cycles of cutting back trees at their base. Willow trees are very fast growing and coppicing doesn't kill the tree: it simply controls their growth rate and fresh shoots soon appear from their bases.

How is the project being funded?

The project has been funded by an appeal to the public by Shropshire Wildlife Trust, plus a large sum from Severn Trent Water and independent funders. A further appeal for ongoing costs, such as fence repairs and volunteer training will be launched in 2022. The Old River Bed is currently managed using Town Council funds, but the release of beavers will mean that this would no longer be the case.

Do beavers carry diseases such as Bovine Tuberculosis?

  • The beavers released are health checked to make sure that they do not carry any infectious parasites or diseases (including the tapeworm Echinococcus), and that they are fit for release both from a disease and a welfare perspective
  • There is no evidence from Europe to suggest that Eurasian beavers carry bovine tuberculosis bTB. As most mammals can be infected by bTB it is theoretically possible for beavers to become infected if they are exposed in English landscapes. Scotland – where the Old River Bed beavers are being sourced from – is currently bTB free. DEFRA has agreed that Scottish beavers therefore do not need to be tested for bTB
  • The Old River Bed is not located anywhere near farmland with cattle and no agricultural land will be impacted by the project

Welsh Beaver Officer, Alicia Leow-Dyke explains some of the key points raised during beaver trials.