Sociable

Monday, 31 May 2010

Ghost Spruces and a Dark Beaver


Yesterday evening a brisk wind blew from the north, so I took station on the southern banks of the Big Pond. After a while the wind became gusty as well as fresh and I realised that it was carrying my scent over the water in turbulent masses. In fact it was quite soon obvious that the couple of beavers that I saw were surprised by these wafts of human scent and splashed their tails and disappeared. 

The wind being chilly, I soon decided to leave but, as I walked past the row of dead Norway spruce that grew along the line of the barrage that retains the pond, I thought these ghosts would make a photograph.

These spruces were drowned by the raising of the level of the pond by the beavers. These days a forester would never be allowed to plant conifers so close to the waterside if he or she was hoping to get a grant for the project. In the 1950s, however, when so little was understood in Britain about the acidification of ground waters by the scavenging of pollutants from the air by conifers needles, it was quite permissible, even best practice, to plant them as close to the water's edge as possible.
Today the wind had turned to the South-East, so our Dutch visitors and I walked out to the Big Pond's northern shore, where the beavers gratified us all by appearing. By way of a change we walked back to the house by the Burnieshed path that is part of the Cateran Trail. 

I was delighted to see this dark beaver, sitting grazing on the opposite bank, just upstream of the lowest of the big dams. He or she went on grazing for a while, then raising itself up on its hind legs, sniffed the air, caught our scent and made a rush for the water.


Sunday, 30 May 2010

Change on the banks of the Burnieshed Burn

Something went awry with my first efforts with this post. The first photograph disappeared as well as the text that should have gone with it. 


Here, however, is a photo of the third dam down on the Burnieshed Burn with Noë Favre, a Swiss exchange student, who is studying geography at Dundee University. I should say 'was' because he returns to Switzerland in June.

The dam continues to grow.



In that same pond is a felled sycamore. You will notice that the bark has been stripped from the trunk. 


And not far away is a single Norway spruce. This has been subjected to some stripping of its bark. The loss of shade that has resulted from the beavers' activities and the odd loss of a tree through wind blow has resulted in a dramatic surge of natural regeneration of birch.

Friday, 21 May 2010

Crathie Bridge to Couttie Bridge on the River Isla

Heading off from under Crathie Bridge just north of Meigle, you find yourself quickly among willow shaded stretches of the River Isla. I soon noticed that the evidence of the presence of beavers in this stretch of the river was very clear. There was much more evidence of activity since I canoed this stretch of the river this time last year.

After an hour and ten minutes or so of easy paddling, with one exception where a fallen tree (wind blown, I think) had created a blockage through and over which I had to drag my boat, I reached the Boat of Aberbothrie. I don't know when this bridge was built, but as the name suggests, a ferry took people across the river at this point before then. 


A few yards upstream of the bridge I paused for a few moments to photograph this little branch with its beaver gnawed twigs.


In the photograph below you can see cattle grazing in the middle distance on the permanent pasture beside the river. I was interested to notice that they had been consuming the canary reed grass at the water's edge.



At some point in the journey I came across this burrow. It looks active to judge by the freshly gnawed twigs.


And later again I passed this impressively felled willow tree.

Down to the confluence with the Ericht there is a lot of willow on the banks of the Isla. Thereafter the riparian landscape becomes more open. There are still clumps of willow, where beavers have left their marks, but these are not so common.

Couttie Bridge crosses the Isla a little north of Coupar Angus. It was built in 1766. Coupar Angus had (still has, but restored about twenty years ago) barracks from which garrisons could mount patrols up into the eastern Highlands in the period after the Risings of 1715 and 1745. Troops must have crossed the river by boat. By 1766 the military threat of the Jacobites had evaporated, so the bridge was probably built for commercial reasons rather than military ones.

The word 'Couttie' comes from mac Ultaich. By the late middle ages the place was called Cuparmacultie. "The cùbar of Ultan's son", from Cùbar Mac Ultain. The Cùbar bit is probably British (Pictish), but its meaning is lost.

From Crathie Bridge to Couttie Bridge is nearly nine miles, a distance I covered in three and a half hours, paddling against the wind for much of the way after the Isla/Ericht confluence.

There were few stretches without recent signs of the beaver.

Wednesday, 19 May 2010

Vegetation in the Big Pond and a Couple of Corrections


Bog Bean (Menyanthes trifoliata) is an important plant around the Big Pond. An exclosure, made by Kevin Jones when he was doing his PhD, shows how much more bog bean there is inside it, protected from the beavers, than lives outside, where it plays a part in the beavers' rations.







Open water, some of it a channel along which the beavers swim, makes up the foreground. Further away is a bank of sedge with a feeding station, on which stripped branches of birch and willow remain. Two thirds of the way up the right side of the photograph, below that leaning birch tree, you can make out a lodge.






Mare's Tail (Hippuris vulgaris) is plentiful along the edges of the pond. I have just learned from Wikipedia (http://en.wikipedia.org/wiki/Common_Mare's_Tail) that 'It has been said to absorb methane in large quantities and so to improve the air quality in the marshes where it is often found.'



I don't know how popular Mare's Tail is with beavers. It always seems to me that they are eating Horse Tail (Equisetum arvense). As beavers pull the slender asparagus like stems to their mouths, I wonder if the plants are edible to humans.

A quick look to Wikipedia (http://en.wikipedia.org/wiki/Equisetum_arvense) assures me that this is so.











Jean-Pierre Choisy has sent me an email to say that his first message was precipitate and contained some errors. He has asked me to post this corrected version of his email.



«Mon cher Ramsay,



Très étonnant... pour rester poli !
Si cela peut aider votre action, je vous autorise pleinement à diffuser ce qui suit, que ce soit en français ou après l'avoir traduit en anglais (dans ce cas après relecture par moi).

Il n'existe dans le monde que deux espèces :
- Castor canadensis, néarctique ;
- Castor fiber paléarctique (Eurasie : absent en Afrique du Nord).
Sauf découvertes récentes, que j'ignorerais, bien sûr.

A la réserve ci-dessus près, opposer un prétendu Castor de Norvège à un Castor d'Eurasie est de l'incompétence taxonomique.
C'est aussi une impropriété linguistique : la Norvège serait-elle hors d'Eurasie?

Jusqu'à il y a une douzaine de milliers d'années, l'Ecosse et la Norvège étaient sous la glace, donc le Castor ne vivait que plus au sud.
C'st à partir de ces populations méridionales que l'espèce a reconquis les régions se libérant de glace, jusqu'à la Scandinavie et jusqu'à la Grande-Bretagne.

Certes, des Insectes avec de nombreuses générations par an peuvent différencier des sous-espèces dans la période écoulée depuis la fin de la dernière glaciation, voire des espèces.
Mais c'est extrêmement douteux chez un Mammifère adulte à quelques années, ne faisant qu'une seule portée par an, d'effectifs réduits.

Il est très possible, néanmoins, qu'on mette en évidence des différences de fréquence d'allèles entre les Castor fiber de diverses régions d'Europe.
En effet quand, comme Castor fiber en Europe, une espèce naguère très répandue sur une aire continue a été réduite à des populations disjointes d'effectifs très faibles, des allèles sont nécessairement perdus par chacune d'elles.
Et il n'y aucune raison que le hasard fasse que ce soit les mêmes qui survivent partout.
Phénomène de dérive génétique par goulot d'étranglement : un grand classique de la génétique des populations, bien connu des étudiants, voire des lycéens.

Il est très douteux, chez une espèce au comportement individuel aussi souple et adaptable, que des différences allèliques éventuelles puissent déterminer des différence éco-éthologiques entre populations de Castor fiber.
Eexemple : en Europe du sud, l'espèce près du gîte, des provisions en fait d'été pour l'hiver. Des individus capturés en France méditerranéenne et se comportant ainsi, relâchés dans des contrées aux hivers plus rude, ont presque aussitôt adopté la manière de vivre "nordique", avec toujours le même génome !

Telle que j'ai pu la lire évoquée sur le site Beavers at Bamff, la position de Scottish Natural Heritage relative aux Castor fiber en Ecosse, si elle ne révèle pas une volonté politique inavouée d'empêcher le retour de l'espèce, prouve une grande incompétence concernant sa biologie.

Jean-Pierre Choisy
Parc Naturel Régional du Vercors,
Biologiste, chargé de mission Faune

PS En 2009, ici, dans les Préalpes du sud, une personne a détruit un barrage de Castor vieux de plus dix ans, sur un site dont l'espèce a, par ses travaux, fortement restauré la biodiversité. Informés, les gardes de l'Office National de la Chasse et de la Faune Sauvage ont dressé procès-verbal, comme ils l'auraient fait pour destruction d'un nid d'oiseau d'espèce protégée, même sans tir de ceux-ci.«

In my own introduction to Jean-Pierre I stated that he had been involved in the programme to reintroduce beavers to the tributaries of the Rhône. This was wrong. The Rhône was one of the places in western Europe where the beaver survived and where it was protected from 1906.

Here is M.Choisy's correcting message with the text I wrote:




'Jean-Pierre Choisy has been closely involved with the return of the griffon vulture, the ibex and the beaver to the mountains of the Vercors.'

«J'ai bien travaillé à la réintroduction dans le Parc Naturel Régional du Vercors du bouquetin des Alpes, du vautour fauve et du gypaète (premiers lâchers imminents).

Mais non pas sur la réintroduction du Castor, qui n'a jamais totalement disparu dans le bassin du Rhône.

Néanmoins j'ai travaillé récemment sur le Castor dans les bassins fluviaux drainant le Vercors

- bassin de la Drôme : retour spontané. Mon travail : déterminer la limite amont actuelle, préconisations pour supprimer certains obstacles artificiels, relations avec riverains ;

- bassin de l'Isère : une partie du cours de cette grande rivière et de ses affluents de rive gauche. Barrages hydro-électriques sur l'Isère empêchant la remontée spontanée. Réintroduction déjà ancienne. J'ai déterminé la limité amont actuelle concernant les marges du Vercors, préconisé des lâchers dans celui-ci et aussi des aménagements permettant de franchir les barrages«.






Friday, 14 May 2010

Digiscoping at the Big Pond

I took this photograph on the evening of the 12th May. It was only after I had downloaded it to my computer that I realised that I had photographed two beavers, swimming along side by side.









The clip of video on youtube was taken the same evening.





The Wet Wood -Spring at last

Heavy rain in the night was followed by a dull morning that brightened. By five pm the weather had cleared and I visited the Wet Wood.

Here is the famous lodge that Roy Dennis built and that the beavers have used ever since with some gaps.






My friend, Jean-Pierre Choisy, bologist to the Parc Naturel du Vercors, has written this response to the post in which I said that SNH would like to see the beavers in the catchment of the Tay removed for being of the wrong provenance.

Jean-Pierre Choisy has been closely involved with the return of the griffon vulture, the ibex and the beaver to the mountains of the Vercors.

Mon cher Ramsay,

Très étonnant... pour rester poli !
Si cela peut aider votre action, je vous autorise pleinement à diffuser ce qui suit, que ce soit en français ou après l'avoir traduit en anglais (dans ce cas après relecture par moi).

Il n'existe dans le monde que deux espèces :
- Castor canadensis, néarctique ;
- Castor fiber paléarctique (Eurasie : absent en Afrique du Nord).
Sauf découvertes récentes, que j'ignorerais, bien sûr.

A la réserve ci-dessus près, opposer un prétendu Castor de Norvège à un Castor d'Eurasie est de l'incompétence taxonomique
C'est aussi une impropriété linguistique : la Norvège serait-elle hors d'Eurasie?

Jusqu'à il y a une douzaine de milliers d'années, l'Ecosse et la Norvège étaient sous la glace, donc le Castor ne vivait que plus au sud.
C'st à partir de ces populations méridionale que l'espèce a reconquis les régions se libérant de glace, jusqu'à la Scandinavie et jusqu'à la Grande-Bretagne.

Certes, des Insectes avec de nombreuses générations par an peuvent différencier des sous-espèces dans la période écoulée depuis la fin de la dernière glaciation.
Mais c'est extrêmement douteux une espèce adulte à quelques années et ne faisant qu'une seule portée par an, d'effectifs réduits.

Il est très possible, néanmoins, qu'on mette en évidence des différences de fréquence d'allèles entre les Castor fiber de diverses régions d'Europe.
En effet quand, comme Castor fiber en Europe, une espèce naguère très répandue sur une aire continue a été réduite à des populations disjointes d'effectifs très faibles, des allèles sont nécessairement perdus par chacune d'elles.
Etil n'y aucune raison que le hasard fasse que ce soit les mêmes qui survivent partout.
Phénomène de dérive génétique par goulot d'étranglement : un grand classique de la génétique des populations, bien connu des étudiants, voire des lycéens.

Il est très douteux, chez une espèce au comportement individuel aussi souple et adaptable, que des différences allèliques éventuelles puissent déterminer des différence éco-éthologiques entre populations de Castor fiber.
Eexemple : en Europe du sud, l'espèce près du gîte, des provisions en fait d'été pour l'hiver. Des individus capturés en France méditerranéenne et se comportant ainsi, relâchés dans des contrées aux hivers plus rude, ont presque aussitôt adopté la manière de vivre "nordique", avec toujours le même génome !

Telle que j'ai pu la lire évoquée sur le site Beavers at Bamff, la position de Scottish Natural Heritage relative aux Castor fiber en Ecosse, si elle ne révèle pas une volonté politique inavouée d'empêcher le retour de l'espèce, prouve une grande incompétence concernant sa biologie.

Jean-Pierre Choisy
Parc Naturel Régional du Vercors,
Biologiste, chargé de mission Faune

PS En 2009, ici, dans les Préalpes du sud, une personne a détruit un barrage de Castor vieux de plus dix ans, sur un site dont l'espèce a, par ses travaux, fortement restauré la biodiversité. Informés, les gardes de l'Office National de la Chasse et de la Faune Sauvage ont dressé procès-verbal, comme ils l'auraient fait pour destruction d'un nid d'oiseau d'espèce protégée, même sans tir de ceux-ci.'

I intend to translate M.Choisy's remarks and post them here again with his approval, but thought that those of you who speak French would like to read what this eminent ecologist thought of SNH's standpoint on the question of the provenance of beavers that have returned to this country.

Comrie Castle to Edradynate

The weather forecast for Thursday, May 13th, was not good, but not very bad. I had arranged with Eddie Palmer that we should meet in the car park of the inn at Grandtully and head on for the Scottish Canoe Association's landing patch at Edradynate. Leaving Eddie's car there we headed on up the road past Aberfeldy and up the lowest stretch of the River Lyon, a tributary of the Tay. There, we put in the canoe and set off.

I didn't see any signs of beavers in the Lyon, but we did see plenty of barking of willow, and the other trees on the water's edge, by red deer. I should have photographed this, but forgot. The barking that the red deer did was a simple strip up each tree trunk. I could imagine the deer using its lower front incisors to scrape up the tree. Deer, cattle and sheep, as you will know, only have incisors on their lower jaws. The upper jaw has a dental pad. Beavers, on the other hand, have teeth on both lower and upper jaws and so do a much neater job when they need to cut something.

The other cutters on the banks of the Tay were the humans. So that fishermen can cast a fly without getting caught up in the vegetation of the banks, the riparian woodland is cut. Biologically this must be a bad thing because it deprives invertebrates of habitat and thus little fish of their food. It also deprives beavers of food until these bankside willows coppice and sprout young shoots.




We stopped for lunch on this island. The water level was very low, so what would ordinarily have been a water way was a bed of gravel.













We saw the first undoubted signs of the presence of beaver by the golf course just below Aberfeldy. This photograph was taken a bit downstream of the golf course.













And here is another one - a branch has been stripped of its bark.

There were plenty of signs of beaver down to Edradynate, where we landed.

The journey was memorable, partly for the signs of beaver, but also for the beauty of the landscape and the abundance of swallows, sand and house martins. Dippers flew and goosanders and mallard went about in their pairs and groups.

There were fishermen, bent over their rods, whom we avoided, but to whom we waved friendly greetings. And mostly the waved back to us.

Wednesday, 12 May 2010

The Upper Baikie Burn


The day after my first visit to the middle section of the Baikie Burn I paid a visit to the upper end of the burn. Not the farthest reach, east of the main road and beyond the saw mill (where they knock out potato boxes), but to the west, where the old steading of the farm has been turned into housing.

We are looking at a small copse of poplars that has been cut over at some time in the past and has coppiced. A third of the way up the photograph on the right is a stem, felled by a beaver. From there on down to the point where I left the Baikie Burn on Tuesday is plenty of evidence of their presence. The Baikie Burn is about two miles long.

On returning to my car by the houses, I encountered a young woman and her son with their rumbustious dogs. I stopped and talked to them and this lady told me that the presence of the beavers was well known in the neighbourhood. She was keen to see them, but hadn't yet done so.

Tuesday, 11 May 2010

A Perambulation along the Baikie Burn

This afternoon I loaded up my Bavarian trap and set off with it for the Hole of Ruthven and the Baikie Burn, which flows nearby down into the River Isla.

I first learned that a beaver was active in the Baikie Burn about last Christmas and went and had a look with James Ivory.

James showed me three trees that had been gnawed or felled and I offered to return with my trap.

But I had lent my trap and the weather made it difficult to head for Strathglass to reclaim it. Besides, I had misgivings about trapping beavers, newly returned to the wild.

Time went by and an unpleasant exchange of words with James's brother, Ian, led me to think that it would be better to take my trap to the Baikie Burn and see what happened.

The photograph above shows what I saw after the three trees that I remembered from my earlier visit. As I walked along the path by the burn I saw more and more similar signs of activity.

In due course I turned back and went a little upstream beyond where I had left my truck. There were still signs and that leads me to believe that the whole length of the Baikie Burn is occupied by at least one and perhaps another family of beavers.


















The Baikie Burn, Dean Water and other streams and rivers are narrow ribbons of relative wild in this wider landscape of monoculture.

The farm in the distance with its grain stores is Islabank.


Monday, 10 May 2010

Bamff - a Map to give you and idea of the geography

http://maps.google.com/maps/ms?hl=en&ie=UTF8&msa=0&msid=106349439316645309329.00048185ef26b27c57d1b&z=13

Antonia asked if I would post a map of Bamff to show the place about which I was writing. I made an outline of Bamff, using My Maps, and have given the link above.

This Spring continues bright and cold. Ardfern, being at sea level was a good deal ahead of Bamff at >200 metres.

Sunday, 9 May 2010

Beavers at Aberfeldy

The River Tay at Aberfeldy or, rather, a little downstream of the town, but looking upstream.

Word had reached me that there were signs of beaver there and, indeed, that someone had set a trap to catch a beaver. Who could this person be, or which organisation?

It seems that Scottish Natural Heritage would like to see all the beavers in the catchment of the Tay removed (and destroyed I must suppose, or perhaps exported to wildlife parks elsewhere in the British Isles).

Why, you may ask, when their plan in 1998 was to return the Eurasian beaver to the Tay, should they do this? The answer seems to be that these Eurasian beavers are the wrong sort of beavers. SNH would have liked Scandinavian beavers to be restored to Scotland and do not approve of the return of beavers from Bavaria that turn out to be descended from Scandinavian, Russo/Polish and French beavers. Not for the them the wisdom of hybridity, but the clonal genotype of the Norwegian beavers. Not that I am against the Norwegian beaver, but it would seem sensible in the case of a restoration, where no original stock survives, to go for hybridity and the advantages that confers, rather than the riskier choice of going for a nearly clonal subspecies.

The difficulty of following museum zoologists' advice is that these folk are easier with the taxonomy of extinct species or dead animals than with the living members of live habitats and ecosystems.

If you scramble down the bank from the car park next to the Aberfeldy cemetery (and on the other side of the road from the Johnnie Walker distillery) this is what you will see.












And a bit more cut stump.

Somewhere along here

Thursday, 6 May 2010

Another Paddle down a section the Dean Water

Another paddle down a section of the Dean Water in Angus. We put the canoe into the water just downstream from the bridge over the A928. Almost immediately there were signs of beaver activity. Many were probably at least one year old, but some were recent.

The local anglers exceeded the beavers by far in their cutting back of willows. To such an extent, I thought, that they might easily deprive the beavers of their winter, and much of their spring, rations. Not so great for the fishermen either, at least not for the fish, who will lose out on the productivity that the willow would have brought.


Here is one of the places where the beavers had been at work in quite a concentrated way. Perhaps there is a burrow in the bank. I didn't notice it when I was taking the photograph, but it looks very likely as I look at the picture.










At home again, I went down to the Big Pond, a cold north wind was blowing, so I went to the south end of the pond and set up my telescope. Eventually this beaver appeared and I set up the digiscope.










I took a number of photographs, of which these are the best and have been cropped because I had not set up the telescope quite centrally to the beaver.














Tuesday, 4 May 2010

A Walk To the Big Pond and back by the Burnieshed Path

Yesterday evening was cold with a sharp northerly wind. Still, we went out to walk by the Big Pond, where we saw three beavers - a dark one, perhaps one of the original sisters, or a descendant. A lighter one was grazing on the sedge by her. After a while this one slid into the water and we could see her nostrils flared as she scented our presence. However, she didn't splash her tail and we walked on.



I wanted to walk to the further corner of what was the Curling Pond, where there is a lot of bog bean (Menyanthes trifoliata) to see if it was coming into flower yet. As we approached I saw a turbulence in the water and watched as another beaver swam out of sight.

The bog bean looked a bit held back by the cold and so we turned to cross the fence of the enclosure and make our way over to the Burnieshed Burn.



A heron landed and watched for prey for a while, but took off when I moved too quickly. Some trouts jumped for insects and we walked back to the house.









Looking back at my post of 2nd May, I must retract the 'never' from the lack of grazing on the reed canary grass. There are signs that it is being grazed, though very little by beavers. Sheep in the neighbouring rough pasture, on the other hand, do seem to be grazing it - perhaps they enjoy the high. I have to retract also my identification of the sweet grass. I am not sure that it is Glyceria maxima. I guess it is Glyceria sp.


Sunday, 2 May 2010

A Walk to the Wet Wood

The warmth of the last days has set off the grasses at last. I am not good at the identification of grasses, but suspect that this is sweet grass (Glyceria maxima). As you can see, something has been grazing it. If it weren't for the fact that the far side, which is hard to reach from the landward side, is next to deep water, I might have suspected the roe deer. In fact I think beavers have grazed this grass.

The leaves don't look it particularly, but the blades and stems are delightfully tender.

I should make the effort and return with a book to identify the grass for once and all. Interestingly this grass is grazed, but the abundant and nearby reed canary grass (Phalaris arundinacea) is not grazed at all. I see from the entry for reed canary grass in Wikipedia that the leaves contain N,N-Dimethyltryptamine (DMT), a naturally-occurring psychedelic drug of the tryptamine family. Perhaps that is what is discouraging the grazers?


The beavers have been busy in this area, extending their dam in different directions to create a cross road of canals.











Here is a bifurcation near the previous photograph.












Bernd Heinrich (in the introduction to his classic work 'Bumblebee Economics') has placed bumblebees in the context of beaver wetlands and made me aware of those insects' tendency to the boreal landscape. Here is the first one that I have managed (or tried) to photograph this year.

I hope that the honeybees in our wall will come out when the weather warms up.