Beyond the weir #1 - The upper Ock

Having surveyed up to the weir, I've spent most of the past week or so exploring beyond it.  The weir divides the river into two - the upper and lower ocks:

I haven't spent much time on the upper ock - it's proximity to the retail units, residential  flats and the amount of undergrowth mean it can be difficult to gain access to the river banks  

Plus I've thought of the weir as a natural barrier for the water voles to progress downstream (and for predators progress upstream). 
Still for the sake of completeness and to assist the BBOWT water vole survey I have spent the past couple of weeks surveying it. 
Although difficult to gain access to, thanks to the use of x40 digital zoom there do seem to water vole burrows

Then on one evening, I saw two water voles - what seemed like a make pursuing a some what reluctant female - by the footbridge near the weir.

So the 2010 water vole map now contains these new sightings in blue.  It also clearly shows weir and the proximity to the other sightings, so despite what I thought, the weir was no barrier at all.

View Water voles 2010 in a larger map

The day in the life of a mayfly

Having spent the past two years as nymphs living in the river and eating algae, the hot weather has bought the mayfly out on mass.  The adult stage has no mouth parts or digestive system and only live for  short period of time - often only a day.

Having emerged from the river they find somewhere suitable for their wings to dry, like this one on a footpath:

The lucky ones find a mate.

The unlucky ones find a spiders web

Or are feed to young starlings:

Those who have successfully mated and reproduced end their one day as an adult dying in the river. Probably eaten by a fish.

Drawing a blank

Last year I filmed a water vole in the ditch running through the middle of the ock meadow:

http://viewsoftheock.blogspot.com/2009/05/water-vole-motion-picture.html

I also found signs of feeding:
http://viewsoftheock.blogspot.com/2009/06/return-to-stream.html

As part of the BBOWT 2010 water vole surveys I have been asked to undertake a full survey to see if water voles are still using the ditch.  The survey involves recording the habitat as well as signs of latrines, burrows, feeding and any sightings.

The ditch is now running dry and is starting to become over grown.

Where I saw the vole last year is also over grown and there is certainly no evidence of water voles inhabiting the area.

Just because there is no obvious evidence of water voles in the ditch does no tmean they're not there. It is quite easy to miss a burrow or a latrine and the length of the sedge means any signs of feeding could easily be hidden.
But even if there are no water voles in the ditch this year, they might return next year and it's important to record the negatives as well as the positives so a complete picture of water voles in Abingdon can be produced.

Towards the weir

The area of the river where it is most likely to see water voles is along a clear stretch from the footbridge up to the Dragons Teeth (a world war 2 defence barrier).  After that, the river becomes covered by trees and soon flows down a weir:

But looking closer shows signs of water voles. Notably burrows, not as many as upstream but still evident

It's also harder to see a water vole, I had to wait half an hour before one popped out:

I eventually saw three, all recorded on the water vole map (in blue):

View Water voles 2010 in a larger map

Speaking to one of the regular dog walkers, water voles have been seen along the lower ock. 

More brown jobs..

Seen by the river Thames this bird - according to the RSPB Handbook of British Birds - seems to be a whitethroat.  One of nearly 20 different types of warbler that can be seen in the UK in spring and summer:

It looks very similar to the lesser whitethroat, but the rear plumage looks darker:

It is a summer visitor, choosing to breed in the UK and then in autumn migrate to North Africa.  Apparently there are an estimated 650,000 breeding pairs in the UK.  As always, I'm happy to be corrected if my identification is incorrect.
This wren is almost unmistakable.  One of the commonest UK birds with an estimated population of 8,000,000 breeding pairs. For such a small bird it has a surprisingly powerful and distinctive song.

Unlike the whitethroat, wrens do not migrate and can suffer as a result. In a harsh winter they can suffer 80%  mortality.

Signs of life on Sandford Brook?

Back in January I considered if water voles were living in Sandford Brook, a stream flowing to the west of the ock meadow and is a tributary of the ock.

It does seem good habitat for water voles - steep banks for burrows and plenty of sources of food:

And there do seem to be new burrows:

And maybe signs of feeding as well:

The water vole map has been updated with a yellow pin (for possible water vole activity) and I will be returning there to see if I can get a sighting before the undergrowth gets too high:

It has also been updated with another sighting on the ock (blue pin for new sighting), towards the bottom of the map:



View Water voles 2010 in a larger map

Blackthorn

The blackthorn growing in the disused canal has now finished it's spring flowering.  But whilst in bloom it was a splendid:

From a distance it looked like the hedgerows were covered in snow:

But up close, the distinctive flowers that bloom in march and april were evident.

Now the blooms have gone and the blackthorn will be starting to produce it's fruit.