Chinese Water Deer

Chinese Water Deer (Hydropotes inermis) are intermediate in size between Muntjac and Roe Deer.  Bucks do not have antlers, but have long canine teeth (tusks) that they use when fighting rivals.  The rut is in mid winter and a doe may give birth to several young in May or June. 

Water Deer were introduced to the park at Woburn Abbey in Bedfordshire at the end of the nineteenth century.  They bred well and were moved around to other collections from which they have escaped or been released.  Along with other species of deer in Britain, they are spreading their range and increasing their numbers, but they remain the rarest of the six deer species established here.  They are most numerous in Norfolk, Suffolk, Cambridgeshire, Bedfordshire and Buckinghamshire. 

Based on likely densities and known distribution, it was estimated that the British population was at about 7000 in 2010, but numbers will have increased since then. Our population may now outnumber that of China, but the Water Deer also occurs in Korea, where it is more common.  It is on the IUCN Red List, classed as ‘Vulnerable’ to extinction on a world scale, so our population is significant from a conservation perspective.

Their history locally

It seems unlikely that Water Deer found their own way from Bedfordshire to the Fens, and there is a story of several from Woburn being released in the vicinity of Woodwalton Fen in about 1950.  The population built up during the 1960s, but the deer were initially assumed to be Muntjac and were not identified as Chinese Water Deer until 1971!  Numbers at Woodwalton Fen did not change much between the mid 1970s and the mid 1990s. 

The graph shows average numbers seen per hour at dusk during winter surveillance, 1976-77 to 2015-16.  It includes deer on adjacent farm fields but excludes those seen further out that were considered to be farm residents. After 1995, changes in the landscape, both inside and outside the NNR, resulted in a marked increase in numbers.  The highest numbers in 2011/12 coincided with the ploughing in of elephant grass on nearby farmland causing the Water Deer that were based in it to return to the reserve. Since then, the population has declined and further time is needed to determine at what level it will stabilise.  

Chinese Water Deer were recorded at Holme Fen NNR from the mid 1970s, with sightings reaching a peak in 1986.  After that, the population declined as they were apparently out-competed in the dry birch woodland by colonising Muntjac.  More recently, with Muntjac being controlled, there has been some recovery in numbers.

The present and the future

Within Woodwalton Fen NNR during the winter of 2015/16, the population was estimated to be just over 100.  Water Deer occur throughout the Reserve, but prefer more open habitats to woodland.  The population is dependent on the conservation grass on the Middle Farm fields closest to the Reserve.  These fields were last cultivated in 2007 and a conservation grass seed mix was sown in 2008.  They provide foraging areas for deer based in the Reserve throughout the year, but particularly during February-April.  The western flood-bank of the reserve at dusk during March or April is the best place in the Great Fen to see this species grazing, resting or indulging in some post-rut chasing.  

Further afield, Water Deer occur at lower densities throughout the Great Fen area.  One of the better places to see them on farmland is in the extreme north of the Great Fen.  Our total local population probably currently amounts to about 2-3% of the national population. 

An old buck in woodland and a young doe in sallow coppice

In general, deer are increasing in Britain and causing worse problems for conservation managers, especially in woodland.  So far, Water Deer are much less of a problem than other species, in part because they are rarer.  They also commonly graze on grasses and sedges, and live in more robust habitats.  Since 2010, it has become apparent that they find fresh re-growth on sallow coppice very palatable – if coppice is heavily browsed, the sallow stools die.  There has been no coppicing recently and it remains to be seen if the population has settled back to a density at which coppice regrowth is usually safe from browsing.

Grazing has been studied on several species of ground flora, including comfrey, which they attack with great gusto in autumn.  This has no immediate conservation significance as comfrey remains abundant on the reserve.  But it does show that scarcer species could be at risk in some situations. 

A buck walking out at night through flooded carr

The photos and videos on this website page were taken during a research project with camera traps to understand better the ecology and potential impact of all species of deer at Woodwalton Fen.  This includes a study of activity cycles in different habitats throughout the 24 hour day. Water Deer can be active at any time of the day or night, but their main periods of activity are around dawn and dusk.  They also feed on the arable fields, often focusing on fields after harvest or on semi-natural vegetation beside ditches.  During the winter, most rutting behaviour occurs during hours of darkness - cameras at the reserve have recorded behaviour not previously filmed, including mating.

As the Great Fen develops, Water Deer numbers are likely to benefit from the creation of wetland habitat such as Rhymes Reedbed.  Unknown factors at this stage include to what degree they will have to compete with other species of deer and how they may react to increasing numbers of visitors.

This summary was revised by Arnold Cooke, May 2016

Other reading

British Deer Society. www.bds.org.uk/chinese_water_deer.html   Includes a fact sheet on Chinese Water Deer.

Also a Booklet on the species: Chinese Water Deer, by Arnold Cooke and Lynne Farrell (1998).  The Mammal Society and the British Deer Society. 

There many excellent photographs of the species at Woodwalton Fen on the Great Fen Flickr pages. 

Videos

Rutting: a doe in season is approached by a buck, but he is chased off by the dominant buck

Grazing on comfrey in an early autumn gale

Doe browsing on sallow re-growth