Pick up any article about water voles and you’ll be reading a quote from
‘The Wind in the Willows’ within the first two lines. It was a favourite of
my father as a child but I never read the book, so the references to ‘Ratty’,
Kenneth Grahame’s literary creation and probably the first and last water vole
to reach national acclaim, pass me by every time. However in my late thirties I
am probably one of the last generation that can remember water voles as a
relatively common sight on our rivers.
Who or what is ‘Ratty’ then? Well certainly not a rat, which is the only
other animal it could be confused with. It is our largest native vole measuring
20cm long and 320g, over 10 times the weight of its next largest ‘cousin’
the field vole. Like other voles it has very small ears, a chubby face, thick
fur and a relatively short tail. Water voles are almost entirely vegetarian and
will eat virtually anything that grows, from reeds and grasses, to herbs and
tree bark. They have a wonderful habit of chopping their food up into bite sized
portions about 8cm long and leaving little stockpiles along the river bank for
later consumption. If you disturb one while it is eating you will often hear a
characteristic ‘plop’ as it dives into the water for the safety of its
burrow.
Having grown up on the banks of the Stour myself I spent much of my childhood
by, or more often in, the river when the extent of my worries was where to leave
the raft rather than the threat of catching weil’s disease from the water I
was splashing around in. So when in 2002 I was asked to carry out a water vole
survey of the entire Stour catchment it was like returning home. Of course I
had no idea what I would find. The Stour was surveyed in 1998 and had good
strong populations along all the Suffolk tributaries such as the Brett, the Glem,
Chad Brook and Box, and a few colonies were still clinging on along the main
river itself. The Stour supports a good population of otters, always a sign of a
healthy habitat, so it was with some optimism that I began my search.
It soon became apparent that all was not well. No signs were evident on long
stretches of the Brett (previously a stronghold) and on the Box only one site
proved positive. No signs could be found on the main channel and what colonies
still held out appeared to be confined to the Chad Brook and river Glem, both of
which run into the Stour just north west of Long Melford. From a healthy 55% of
all sites surveyed in 1998, only 24% were still occupied just 4 short years
later.
So what was happening? Surely the habitat, which still appeared very suitable
along most of these stretches, could not have changed so vastly over such a
short space of time? It was during this time that I was introduced to Iain
Grahame at Daws Hall nature reserve near Lamarsh. The Daws Hall Trust had been
concerned about mink numbers for some time and the possible link between their
appearance and the absence of water voles so we both agreed that further surveys
of isolated sites which fell outside the main river survey were required. The
following summer I stowed my thermos, waders and clipboard in the back of the
beaten up Vauxhall and set off once more along the valley.
I checked ponds, streams, ditches and the entire length of the Losh House
Brook which runs through two nature reserves, including Daws Hall. Most sites
had reported water voles within the last few years but to my horror I found only
empty burrows and no signs of the animals themselves. They had disappeared
seemingly overnight. Again and again I heard tales of thriving populations dying
out after sightings of mink nearby and it became apparent that these alien
predators were having a marked impact on water vole colonies.
Water voles are surprisingly ill adapted to an aquatic life. Their fur
becomes easily water logged, they have none of the webbing on their feet
associated with many water dwelling animals, and they are slow swimmers. However
they have survived predation from a range of aerial and terrestrial attackers by
diving into underwater burrows and kicking up a trail of silt to disguise their
retreat. Unfortunately a female mink is not fooled by this behaviour and using
scent, rather than sight, to track her prey she is small enough to get into
burrows and hunt underground. During the breeding season, a water vole colony
must seem like a walk in larder.
So what is the future for water voles on the Stour? Thankfully we have a good
idea of where their strongholds are. If they are able to move back down these
tributaries and into the river itself they can recolonise naturally, so the key
to their survival is to remove mink from the area around Melford and Sudbury and
keep them excluded. A major effort is being made by the Daws Hall Trust to
co-ordinate landowners and game keepers along the Stour, and indeed the river
Colne to the south, and further monitoring is planned for 2005.
One thing is certain, water voles are a wonderful part of our natural history
and charming to observe as they sit on the bank chewing at particularly tasty
leaves and grasses. It would be a shame to think that like the red squirrel they
may become just a memory for most of us, sidelined into tiny refuges when once
they were so numerous. There is still hope that this gloomy future may be
averted so with good luck and a bit of effort perhaps they can be saved. In the
meantime I’ll dust off that copy of ‘The Wind in the Willows’ and learn my
quotes before writing my next article.
Darren is keen to hear from any readers who have
seen (or suspect they have seen) water voles in Suffolk or Essex in the last
year. As part of our ongoing work to conserve these creatures it is vital to
locate all existing colonies.
If you have any information or just wish to learn
more about Colchester Natural History Society please contact Darren by email darren@ecotrack.co.uk
or tel/fax 01206 510023.
