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Mammals of MWHG


Water vole (Arvicola amphibius)

Once a relatively common sight on our waterways, the water vole is now a rare treat to behold. Since the 1960s, water voles have disappeared from 90% of sites in England where they were previously known to have lived. The crash in water vole numbers has been one of the fastest and most severe of any mammal species in Britain. 

Water vole (Arvicola amphibius)

Water vole (Arvicola amphibius)

The main threats to water voles include the following: 

  • Habitat loss and fragmentation 

  • Water pollution 

  • Rat poison 

  • Reinforced canal and riverbanks with non-natural materials – this is called ‘piling’ – leaving no soil for water voles to burrow into 

  • Flooding and drainage which can drown water voles in their burrows 

  • Trampling of banks and burrows by machinery and livestock 

  • Predation by the American mink 


Water voles are a vital part of the wetland ecosystem. They eat a wide variety of plants, preventing over-domination by a single species and play a role in the dispersal of seeds and rhizome roots. We are incredibly lucky to have a strong population of water voles on the Manhood Peninsula. Water voles can be shy and secretive so can be difficult to spot, just the rustle of vegetation, the sound of a ‘plop’ in the water or a fleeting glance as they swim rapidly away. 


Water voles have a rich dark brown coat, it can be reddish on the back and greyer on the stomach area. Very rarely, usually in Scottish populations, they can be black. Adults are about 30cm long nose to tail and can easily be confused with brown rats. 

Field signs
You are much more likely to see signs of water voles, rather than the animal itself! 


  • A ‘plop’ sound near the water’s edge. This will be the sound of water vole heading off when it hears you approach! 

  • Burrows are dug into the banks and can be above or below the water depending on its current level. One water vole burrow will often have multiple entrances. Look for small holes 4-8cm wide with a little ‘lawn’ of nibbled grass nearby. 

  • Latrines – water voles leave droppings in piles, often in a conspicuous place near their burrow such as on a ledge or rock. These piles are called latrines. Droppings are about 1cm long and 5mm wide with blunt ends, often described as cigar-shaped. They are green-brown in colour and do not smell, but if you pick them up you will still need to wash your hands! If you find smelly droppings, these are probably from a rat. 

  • Footprints – it is difficult to tell the difference between a water vole and rat footprint. They both have the same star-shaped 4-toed foot at the front. Rat prints are bigger, and the toes are less splayed and more forward-facing. Rats also tend to leave a tail drag line behind them, which water voles rarely do. 

  • Vegetation piles – water voles sit on their haunches to eat and leave little piles of vegetation stems cut at a 45-degree angle, as stockpiles for later. 

  • Runs – water voles make little tracks in the vegetation between their burrow entrances and feeding places. These are different from rat runs which appear as criss-crossed paths leading between rat burrows.

Legal status
Water voles are fully protected by law under Schedule 5 of the Wildlife and Countryside Act 1981 (as amended), making it an offence to damage, destroy or obstruct access to a water vole’s burrow or area of shelter, as well as to kill, injure, possess or sell a water vole. Under this legislation it is illegal to handle a water vole or survey for one by trapping without a licence. Licences are issues by Natural England.

The Group’s Heritage Lottery Funded conservation project, Fixing and Linking Our Wetlands (FLOW), restored many wetland areas on the Peninsula and restored them to good quality water vole habitat. The FLOW project also controlled American mink populations to reduce water vole predation and raised awareness of wetland conservation among local communities. 

Download our ditch management leaflet if you have a ditch, rife or watercourse on your land so that you can manage your land for water voles and other wetland wildlife. 


American mink (Neovison vison)

American mink (Neovison vison)

Since the 1950s, following escapes from fur farms, the non-native invasive American mink has become widely established in the wild throughout the UK. They have had a huge impact on our native fauna through the predation of birds and small mammals, including the rapidly declining water vole.

The pressure of mink predation, on top of habitat loss and fragmentation, has led to a 90% decline in water voles in Sussex. Because of this, mink control has been accepted as an essential tool to help conserve remaining key populations of water vole. 


The Fixing and Linking Our Wetlands project established a mink monitoring scheme using monitoring rafts that float on water. These rafts, situated in ditches and rifes, have a tunnel covering a clay pad. When an animal walks on the clay, it leaves footprints, and we can identify the species later. The rafts are checked weekly by two very dedicated volunteers.


Once mink are detected, the raft on which it left its tracks also becomes the best place to set a trap, so that the mink can then be humanely and legally destroyed. 


As well as monitoring mink, the rafts help us collect evidence on the whereabouts of water voles, and some unexpected, rare species have made an appearance, including otter, bittern, and water rail.


We are lucky enough to have all 18 species of British bat in Sussex. Many of these species can be found on the Peninsula and you are most likely to see them hunting at night. Bats play a key role in the food chain as a major predator of flying insects.

Bats live in towns, cities, and countryside in the UK. They are most active in summer between May and October when they hunt insects, breed and raise young. The best way to spot bats is to head out just before sunset or sunrise, in warm, dry weather.  


Bats rely on natural corridors to commute to and from roosting and feeding sites. These flight lines tend to be along hedgerows, field margins, woodland edges, and ditches. Some bats will travel up to 30km in one night to feed. All bats in the UK are legally protected because their numbers are threatened by significant losses of roosting sites including ancient trees and old buildings, developments affecting flight lines, and dwindling global insect populations. 


Did you know, bats are particularly sensitive to artificial light? Torches, car lights and streetlamps can have a disruptive effect on bats hunting at night. If you are spotting bats at night, take a torch that has a red light, as this does not affect bat hunting behaviour. 

Pipistrelle bat (Pipistrellus pipistrellus)

 Pipistrelle bat (Pipistrellus pipistrellus) 

Species that you might spot on the Peninsula include: 
Common pipistrelle (Pipistrellus pipistrellus)  – Britain’s smallest bat, but also the commonest and most widespread. They emerge about 20 minutes after sunset and have a quick, erratic flight as they dart around trees, hedges and buildings. They will hunt around water features like ditches and ponds as well as woodland and gardens. 
Soprano pipistrelle (Pipistrellus pygmaeus) – Another common and widespread species you are likely to see. The soprano pipistrelle’s flight is very similar to the common pipistrelle although they are slightly smaller. These tiny bats can eat up to 3,000 insects in one night! 
Daubenton’s bat (Myotis daubentoni) – A medium-sized bat that is associated with water. They can be spotted skimming the surface of a pond foraging for aquatic insects like mosquitoes, caddisflies and mayflies. This bat can even use its feet and tail to pick off insects from the water’s surface! 
Noctule bat (Nyctalus noctula) – This large bat sometimes emerges before sunset and has a characteristically powerful, direct flight. They will often fly out in the open, above tree-top level, and can be seen diving for insects when foraging. They like to roost in trees, preferring old woodpecker holes and rotten cavities. 
Serotine bat (Eptesicus serotinus)  – Another large bat that can be seen flying before sunset. They will glide and slowly flap their broad wings in flight, taking steep dives when pursuing insects. They will fly at tree-top height close to vegetation or hedgerows and will sometimes briefly land on leaves or twigs to catch an insect, especially for their favourite food, beetles! 

Common seal (Phoca vitulina)

Common seal (Phoca vitulina)

Chichester Harbour is home to the Eastern English Channel’s only known rookery (seal breeding ground). Common seals live in The Solent and are often spotted bobbing in the shallow waters of the harbour, or basking on mud flats, away from human disturbance.

The Harbour contains plenty of fish and crustaceans, and lots of quiet places for them to rest, breed and raise young. If you are lucky enough to see them, please ensure you are a good distance of at least 100m away. Too much interference may deter the seals from breeding here in the future.

Did you know, every common seal has its own unique colour markings, and they can be any colour from black, brown, tan, or grey?

We occasionally see Atlantic grey seals (Halichoerus grypus), the common seal’s larger cousin, in Chichester Harbour. 

More information: Chichester Harbour Conservancy.


Otter (Lutra lutra)

Otter (Lutra lutra)

The occasional otter will turn up on the Peninsula, but they are not a common sight and do not tend to build their holts (dens) here. Otters require large river or coastal territories and eat lots of fish, so the small ditches and rifes on the Peninsula would not be adequate for them. The mink monitoring camera and footprint traps have occasionally picked up the odd sign of an otter, however, so it is possible that they come here when passing through seeking new territories. 

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