Aigronne Valley Wildlife pages

Sunday, 6 May 2012

Flocking finches!

Not because they keep emptying the feeders....
but...
We've noticed in the last week that there is quite a large flock* of European Goldfinches [Carduelis carduelis] Chardonneret élégant flying around here....
something normally associated with the winter months
[alright... I know it is cold enough].

One of our Goldfinches


There are three possibilities for this behaviour....
Firstly, that these are bachelor boys from last years broods that haven't found a mate... but those groups are normally smaller.
Secondly, that it is just too cold and wet to nest, with not enough food available... so they've regrouped for safety in numbers.
Finally, there isn't enough cover to nest in.

The last could have something to do with the heavy clearance that is going on on the riverbanks, but I doubt it as, in the scheme of things it is removing very little of the actual available cover.
A few tens of metres either way there will be brambles and blackthorn... with more on the wood edges.
However, it could be as a direct result of the very slow growth in some of the vegetation that they normally nest in... the bramble especially!

Dead bramble that provides no cover....
...if you follow the willow trunk down you will see it through the dead clump.
 Our brambles [Rubus ssp] haven't got going at all yet... the freeze in February hit them very hard, killing off most of the exposed shoots and buds... those that weren't tried to open in the exceptionally warm March... only to be hit by another blast of heavy frost just as they had done so.

The brown patch is a huge clump of bramble by the last of the five pollards.
You can't kill bramble that way, but it now has to come from the base, or form adventitious buds up surviving stems and grow from those. Whichever way it happens, this is a very slow process to begin with and will probably delay nesting for weeks for some species.


* more than 40.

Wednesday, 2 May 2012

Improving the Aigronne part II

The planned amenagement of the Aigronne valley continued rapidly this spring between Le Grand Pressigny and at least Charnizay. The work we blogged about here to improve the river flow has settled in nicely, with green algae and sediment softening the whiteness of the new stone. The "restoration" of the riverside vegetation has proved rather more controversial.

Acting to preserve the environment

Vegetation in a bad state:
     presence of unstable trees, leaning, withering, dead
     poplars in great numbers
     zones inaccessible to users (fishermen... )
     presence of trunks and branches in the bed of the river
Work done:
     Cutting down trees threatening to fall into the river in the medium term
     Creation of clearings to enable users to reach the river
     Selective removal of encumbrances on the river bed
Many of the poplar plantations in this area are way beyond any economic return, being good for nothing but firewood. Poplar is an excellent constructional timber, and according to one tradition we have heard, new parents plant poplars on the birth of a daughter, with the eventual proceeds to pay for her dowry. That would make a poplar harvest at about twenty years old, but many of these trees are much older. They are loaded with heavy balls of mistletoe (gui), and many trunks have heart rot.

Rotten poplar trunks near Le Moulin Neuf
The stump in the foreground of the picture above typifies the problem trees. It is all that remains of a poplar that crashed across the road in last winter's storms, which tipped it over roots and all. The stump has been carefully relocated, to preserve the line of the riverbank and the streamlet that empties into the river via the ditch.

It is good to see so many of these rotten old poplars waiting to be taken away. We are speculating whether some of the large piles of "lop and top" such as the one on the far bank are awaiting a mobile chipper so the scrap wood can be made into pellets for fuel.
 
But the scale of clearing along the riverbanks is causing some riverains some concern. Along the Aigronne. and its tributaries such as the Rémillon below La Celle Guenand, all the riverside trees and shrubs, regardless of species, have been coppiced (cut to the ground) in some places. Yohann Sionneau, the river technician, insists that his team have been removing nothing but poplars, in accordance with their policy. But, he said, some individual proprietors, working on their own stretches of river, had been rather too enthusiastic.

Bare banks - not much cover here!
Coppicing will not kill the living trees, and is necessary from time to time, but for so many proprietors to do it simultaneously is "too much" as our neighbour Anne said. The trees will regrow enough to provide some cover in a couple of years. However, before that happens the amount of shade along the Aigronne - a premier trout stream - between Charnizay and Le Grand Pressigny has been massively reduced, all at once. In hot weather the water will become warm, the oxygen level will fall and the fish will die. We have heard from someone involved with La Gaule Pressignoise (our local fishing association) that of a recent release of trout, six were picked up dead.

The trees and shrubs along the river provide an essential wildlife corridor, linking isolated patches of woodland and enabling birds, mammals and insects to find food or a mate or a nest site or somewhere to roost. The cover will grow back, but right now the banks are bald. We have not seen a single squirrel this winter - we saw them regularly last year. However we have heard three great spotted woodpeckers drumming simultaneously at different points along our still-covered stretch of riverbank. We have not yet heard an oriole, that lover of poplar plantations - many poplars have gone, but there are still plenty left for the orioles.
Wildlife corridor along the Rémillon