Sunday 4 March 2012

Bumper year for water voles?

There is plenty of evidence of water vole activity along the river at the moment, the are many freshly dug burrows in the river bank (probably old burrows being renovated).
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Some of the burrows have small cut grass stems in front of them - evidence of water vole feeding.
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The main give away of increased activity are obvious latrines, water voles define their territory by using their droppings and are most evident during the breeding season:
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Of course, the most obvious sign of water vole activity is actually seeing one and this one is making up for the lack of edible river fauna by eating the bark and lichen from one of the overhanging willow trees.
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Even though spring has not yet started, there does seem to be plenty of water vole activity already, perhaps there are several reasons....


The main contributing factor to the 90% decline in the UK water vole population since the 1950's is the release of american mink from fur farms (now banned in the UK) and mink  have been previously seen by the nearby river Thames.  
Although mink and otters can co-exist (the mink become diurnal - active during daylight) last years breeding female otter would almost certainly not tolerated a such a predator close to her cubs and would either kill or chase off a mink - to the benefit of the water voles. 


Water voles don't hibernate, so have to forage during winter - feeding off roots, tubers and as above bark and lichen off the overhanging willow trees.  However, the mild winter (with the exception of one or two weeks) has meant the voles would not have perished through the cold and would have more opportunity to feed.


Another common cause of mortality for water voles is drowning (perhaps surprising for an animal which choses to live by rivers), they can often be trapped in their burrows when water levels rise quickly.  Something which often occurs on the Ock.  So whilst the potential draught in the south of England could cause problems for other wildlife - especially amphibians (http://www.bbc.co.uk/nature/17130206)  - it could benefit the water voles on the Ock.


As a result of these, could 2012 will be a bumber year for water voles on the Ock?

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