Mammals

Wicken Fen provides a large number of habitats in which mammals and evidence of their presence may be found. Some species are permanently present and several others visit the Fen.

In 1923, in the book The Natural History of Wicken Fen, Evans considered that ‘we have no constantly resident Wicken Fen mammals except the rodents’. This is not true today.  We can now see shrews, mole, stoat, weasel and fox throughout the year in addition to rabbit and the small rodents. When the water table is high and flooding occurs all the species find refuges in the slightly elevated areas. There are also a wide range of habitats for mammals in the land The National Trust has acquired to the south of the Sedge Fen. Thus mammals may be more numerous in the 21^st century at Wicken than they were in past years.

It is never easy to see mammals when walking in the country but with luck and perseverance most people should have some success. Deer, rabbits and brown hares are the most likely species to be seen at Wicken. There are also tracks and signs to look out for such as footprints, fur, and scats, droppings and spraints (poo!).

Mammal Species that have been seen at Wicken Fen nature reserve

Brown long-eared bat (Plecotus auritus) - Occasionally caught in mist nets by bird ringers, and released.
Noctule bat (Nyctalus noctula) - Commonly seen on suitable evenings. Tends to fly early in the evening, usually fast and high. It is often audible, making a shrill metallic squeak when it is hunting.
Common Pipistrelle bat (Pipistrellus pipistrellus) - A very common species. It is often seen flying, with its rapid wing beat, around buildings and elsewhere at dusk.
Soprano Pipistelle (Pipistrellus pygmaeus) - Occasionally recorded on bat detectors. There is probably a roost in a nearby building to the Fen.
Daubenton’s bat (Myotis daubentoni) - Has been noted to forage along the Lode.
Whiskered Bat (Myotis mystacinus) - A roost occurred in one of the Fen buildings. Not sure if it is still present.

Otter (Lutra lutra) - The otter is back at Wicken Fen after an absence of many years. The improvement in the quality of our rivers, the banning of some pesticides, and legal protection, has helped the otter population to recover in Britain. It is now possible to find otter spraints (poo) at Wicken on occasions.

Photo (right) shows the prints of an otter

Hedgehog (Erinaceus europaeus) - Resident on the Fen and found hibernating in bramble patches on the drier areas of the reserve.
Mole (Talpa euronaea) - Abundant all over the Fen except in the very wet areas during flooding. Dead, presumably drowned, individuals may be observed in flooded areas. Tunnels close to the surface and the mounds of excavated earth are obvious on the droves.
Common Shrew (Sorex arumeus) - Abundant throughout the Fen and very tolerant of wet conditions. A few albino specimens have been recorded.
Pygmy Shrew (Sorex minutus) - Occasional in all habitats.
Water Shrew (Neomys fodians) - Trapping results indicate that this species is only occasionally present in sedge fields and fen carr. However, it is the most common species found dead on the ground.
Fox (Vulpes vulpes) - Probably breeds regularly on the Fen, but it is not often seen. Foxes have also seen on the restored habitats of Guinea Hall Fen and Burwell Fen.
Stoat (Mustela erminea) - Occasionally observed and probably resident on Adventurers’ Fen and Wicken Sedge Fen. Individuals with some white hair have been seen in winter. Sight records suggest that it is more common than the weasel.
Weasel (Mustela nivalis) - Occasionally seen and trapped in sedge fields, fen carr and their droves.
American Mink (Mustela vison) - An introduced species now feral after escaping from the fur farms. It is occasionally seen on Wicken Fen, but we do not know if it breeds here.

Brown Hare (Lepus capensis) - Resident and breeding on Adventurers’ Fen and Guinea Hall. It is an occasional visitor to Wicken Sedge Fen. Photo, below, courtesy  of Kevin Simmonds.

Rabbit (Oryctolagus cuniculus) - Large colonies present along the waterproof banks on Adventurers’ Fen. Confined to the village end of Sedge Fen and the Brickpits area on Little Breed Fen.
Grey Squirrel (Sciurus carolinensis) - Resident and breeding in small numbers in the mature trees near the brickpits and the north side of Wicken Fen. Commonly seen bounding along droves and in areas of fen carr.

Harvest Mouse (Micromys minitus) - Common at ground level in sedge fields during autumn and winter (revealed by live-trapping). Possibly resident all the year at higher levels. Nests have been found in reeds on Adventurers’ Fen. Evans (1923) records show that they bred in the neighbouring fields at that time. Photo, right, courtesy of Kevin Simmonds.

Wood Mouse (Apodemus sylvaticus) - Common in the fen carr, sedge and litter fields. Never reaches high densities.
House Mouse (Mus musculus) - Rare in sedge fields where a few individuals may occur during the summer months.
Brown Rat (Rattus nervagicus) - Occasionally seen near buildings around the Fen. The 1947 edition of the Wicken Fen Guide states that brown rats were common in the flooded Adventurers’ Fen in 1931-40, living in the half-submerged sedge tussocks. They were almost completely aquatic and ate the eggs and young of black-headed gulls and waterfowl.
Bank Vole (Clethrionomys glareolus) - Usually abundant in sedge fields, litter fields and fen carr wherever the ground cover is dense. In dry years peak number numbers are reached in July or August.
Water Vole (Arvicola terrestris) - This threatened and declining species was common along the lodes and ditches at Wicken Fen in the 1970s. However, numbers declined in the 1980s and it was probably locally extinct by 1990. The good news is that water voles are back at Wicken, with several sightings in 2006. One pair took up residence in the pond by the Visitor Centre in 2007.
Field Vole (Microtus agrestis) - Common in letter and sedge fields wherever grasses replace, or are mixed with, reeds and sedge. They are generally absent from stands of pure reeds and from fen carr.
Coypu (Myocaster coypus) - One individual was trapped in April 1978 at Wicken. This was an introduced species which escaped from fur farms, and was eradicated from Britain in the 1980s.

Roe Deer (Capreolus capreolus) - Very few Roe Deer were seen at Wicken until new wet grassland areas were created as part of the Wicken Vision. Now small groups can often be seen on Burwell Fen. 16 were seen on one occasion in 2006. Photo, below, courtesy of Kevin Simmonds.