On the trail of Otters and Beavers in La Vienne
20 years or so ago it would have been impossible to find an
Otter or Beaver in any of the rivers and waterways of the Vienne department of
France; in fact, the Otter was almost pushed to extinction in France and was
only to be found in the Atlantic regions and the Massif Central by the 1980’s.
Since then, there has been a steady improvement, with continuous recolonisation inland towards the east along the main river systems and
their tributaries. In the Vienne department, we have the Charente, which enters the sea near Rochefort, and
the Vienne, a tributary of the Loire .
Both of these rivers also have numerous tributaries; notably, in the Vienne,
these are the Clain and the Gartempe, which again have their tributaries.
The situation with Beavers is somewhat different, following their extinction in most of France, with reintroduction being required in many places.
The only river in Poitou Charentes where a reintroduction
was attempted was the Creuse in Vienne where 4 beavers
were released during 1970-1973 and this failed but this wasn’t the end for our
region. During the period 1974-1976 13 beavers were released in the river Loir
in Loir-et-Cher and during 1994-1996 another 13 were released in the river Loir
in Loir both being successful. From the river Loir the
Beavers have bred and slowly increased their range and are now present for us
in the rivers Vienne , Creuse, Gartempe, Anglin,
Salleron, Clain, Thouet, Argenton and la Dive du Nord.
One of the many tasks undertaken by the recognised Nature
Associations along with the ONCFS (Office National de la Chasse et de la Faune
Sauvage) is to research and monitor the presence and range expansion of both
species and in the Vienne there are several days of research dedicated to this
in most years by Vienne Nature along with a small number of volunteers. This requires
the relatively simple practice of seeking out signs of their respective
activity.
For European Beaver, this is dam creation, small tree felling, and small gnawed or stripped pieces of branch with their distinctive chiseling patterns.
For otters, it is spraints (otter excrement), footprints, and
remains of prey, crayfish claws, fish heads, and frogs/toads that have had their
insides eaten. Great care needs to be taken with the remains of prey that could
result from other activity, anglers in the case of fish and crayfish remains, and also polecats (Poutois), for Crayfish and frog and toad remains. Generally, frog and toad remains (known as
“carnage”) should not be taken as concrete proof but are a good indication
when spraints have also been found within a few kilometres.
With this in mind, I set out with Miguel Gailledrat of Vienne
Nature the other week for a day on the Boivre, a small river that rises in
Vasles, Deux-Sèvres, and enters the river Clain in Poitiers .
Its name, La Boivre, is thought to be derived from the ancient French word Bièvre
for Beaver and is today also called Rivière aux castors or “beaver river,”
although there is no evidence that Beavers were ever here, and it wasn't Beavers
we were looking for in this river but otters, although it's quite probable that they will colonise the Boivre in time.
I should mention that although the principal purpose was to
look for signs of otters, we would also record any signs of Coypu, Southern
Water Vole, and any freshwater clams or mussels, and indeed anything else
noteworthy, but not plants, although I’ve included a few photos! The idea is to
look at all the bridges and ideally look for 150 metres or more either side of
the river on both sides of the bridge, if this is possible, which unfortunately
it often isn’t. When only one side of the river is accessible, the use of field
glasses may assist in viewing any flat surfaces on the opposite bank.
Click images to enlarge.
The Boivre is the last river in the Vienne dapartement where
no signs of otters have been recorded, and we were hopeful that we could change
that and complete the map, and remarkably the very first bridge visited produced
spraints on the concrete reinforcements on both sides of the river – what a
great start to the day!
The rest of the day continued with some success, with more
spraints at different locations, one really fresh! Also found in three
locations were toad and frog carcasses, plenty of traces of wild boar and roe
deer, coypu excrement, and some freshwater mussel, (Potomida littoralis), but for me another important and interesting
discovery was some Southern water vole, (Arvicola
sapidus), excrement on some rocks by a bridge, a protected species which is
being recorded Nationally.
The situation with the Beaver in the River Clain is that
traces of activity have been found in the northern part of Poitiers, and it’s
hoped that they will move through the city and out to the south.
Otter in France
European Beaver in France
Southern Water Vole in France
Chris
