mammals
The presence of warm-blooded creatures with
backbones, known as mammals, can indicate good water quality in
a nearby stream or river. Many well-known creatures that are mammals
that live close by streams and rivers. They rely on invertebrate
(B09a), amphibian and fish
life (B09d) in the water, as well as on the
riverbank and nearby land, for food.
Some of the mammals that depend
upon rivers and streams are shy or nocturnal and so it will be difficult
for you to catch a glimpse of them when you are undertaking fieldwork
or visiting a stretch of water. Instead you might be able to identify
signs that the mammals have left behind.
Otters are shy and are most active at dawn and
dusk especially in the summer time. The presence of an otter is
a very good sign as the area will be undisturbed and there are most
likely to be large fish, like salmon, in the river. We know fish
are good indicators of good water quality (B09d).
The main signs to look for, indicating
that otters live along a stretch of river, are their droppings and
tracks. Droppings are usually found on raised places like rocks
or tree stumps along riverbanks. The droppings, when fresh, are
black and tarry with an oily smell and are full of tiny, sharp,
fish bones. Otter tracks may be seen in soft mud, you might be able
to identify five toes and webs on the large round footprint. A local
expert can confirm your findings by positively identifying the droppings
- see section on Animal Tracks (B06a).
Draw pictures to record your findings.
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Water Vole |
Water voles have not been seen
in Cornwall for many years because another mammal, the mink, was
introduced into this country and it was better at competing for
space and food. The habitats of water voles are now protected by
law in this country and through careful habitat management, controlling
mink and reintroducing water voles into suitable areas, it is hoped
that numbers will increase in the south-west region.
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Water shrew |
Some mammals can live in other habitats but are often found in wetland
areas near rivers, the harvest mouse and field vole are two examples.
The water shrew can be found far away from water in woodland, grassland
or hedgerows but you would be most likely to see it on the banks
of clear, fast-flowing and unpolluted rivers and streams. This mammal
swims and dives foraging for invertebrates (B09a),
small fish, frogs and newts. Freshwater crustaceans are a water
shrew’s favourite feast!
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Frog |
Perhaps you will be lucky enough
to see other mammals or signs of them along a riverbank. Foxes,
deer and badgers all leave signs that they have visited or live
in an area. You might be able to spot their tracks in the soft soil
along a river-side footpath or see signs that they have been there.
Creatures have some intriguing habits and ways of marking their
territory. To find out more visit the Devon and Cornwall Wildlife
Watch website.
Cornwall
Wildlife Watch website
or
Devon
Wildlife Watch website
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Daubenton's Bat |
But some mammals, such as bats,
you won’t be able to find by their tracks, and you might have
to wait until nightfall to even notice that they may be there. It
is only then that you will be able to see this winged mammal in
action cleverly hunting its prey. Many different varieties of bat
have been identified in Britain and most of them feed over water
on moths and other winged insects which appear at dusk. Some bats,
however, prefer to eat big land-roaming beetles. What effect might
the use of insecticides have on such animals?
To find out more about bats visit The
Bat Conservation Trust website
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Daubenton's Bat
- courtesy of The Bat Conservation Trust/J Kaczanow |
You may have heard some people
talk about biodiversity (B06)
and the ‘Biodiversity Action Plan’ (sometimes shortened
to BAP). The plan looks at all the wildlife (mammals, plants, fish,
invertebrates, amphibians and birds) in the UK, and sets out improvements
that should be made to stop habitats and wildlife being lost and
help them to recover. There are regional plans and guides to help
the national BAP work, the south-west has one. To find out more
visit the BAP website.
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