Meanwhile at Radley Brook..

Any regular readers will know that the Ock water voles are not the only ones to feature in this blog, there is another population at Radley Brook in North East Abingdon:
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It is a small ditch and suffers the same problems as the Ock - frequent flooding and possible predation by mink, but being only a few metres from the Thames these are even more likely.
But despite this there is a stable water vole population, which can be very hard to see due to the amount of Sedge:
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But with a lot of patience over many days it is possible to catch a glimpse of one of them, as they lurk amongst the sedge.
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No water voles?

Up in Shropshire, Kate seems to be seeing a water vole boom - where the voles have become so brave she is even feeding them by hand (as well as getting some great photographs):

http://staggsbrook.blogspot.co.uk/2013/08/when-voles-grow-bold.html

However, along the Ock, it is a more solemn story, where last year there were water voles feeding on the arrow heads, this year they remain untouched:
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This has lack of grazing has allowed some of the river plants to flower, including this flowering rush:
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When there is an obvious decline in a water vole population the first suspect is the presence of american mink.
However, there are several young moorhen of different ages (more than last year), which are often a favourite of mink:
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So maybe the reason is more complex - perhaps this years wet winter followed by a very wet spring combined with a natural low breeding cycle has resulted in a lower population.
However, along the Lower Ock, there are signs of water vole activity, a latrine:
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As there is over 20 miles of water vole habitat along the Ock and its tributaries and as water voles are fast breeders it is very likely that the water vole population will once again increase in subsequent years.
That is of course assuming that reason for the decline is not the presence of mink....

The rarest creature in Oxfordshire?

When thinking of what might be rarest creature in Oxfordshire it's easy to think of the large mammals which get a lot of media interest - the otter, once extinct from virtually all of England or the water vole - the fastest declining mammal in England and still missing from a lot of it's previous sites.
But probably the rarest animal is a creature that we wouldn't recognise even if we did actually get to see it and a contender is an insect found only in a couple of very small streams within the Cothill Fens - a series of nature reserves outside of Abingdon that feed Sandford Brook - a tributary of the Ock:
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From a distance, it looks like any of the small blue damselflies that are found around rivers and ponds at this time of year.
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And it requires a closer inspection to reveal the markings of the Southern Damslefly:

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What distinguishes it from the other small blue damselflies is the markings on the top of the abdomen.

An insect so rare that is only found in a very few sites -  shallow base-rich streams within an acidic heathland - and the UK population is estimated to be a quarter of  global population.
Yet the Oxfordshire population is so small and fragile that it doesn't even get mentioned in some field  guides.

It's scarcity lead it to be one of the insects that feature in a series of stamps released in 2008 to highlight the plight faced by many UK insects.

http://www.norphil.co.uk/2008/04b-endangered_insects.htm


References:

http://jncc.defra.gov.uk/protectedsites/sacselection/species.asp?FeatureIntCode=S1044
http://www.british-dragonflies.org.uk/species/southern-damselfly
Dragonflies & Damselflies of Great Britain & Ireland - Brooks & Lewington