Sociable

Sunday, 31 May 2009

Release at Knapdale and a Paddle down the River Isla







Here I am, minus Vari-shade spectacles so as not to look too sinister. The photographer from 'The Times', James Glossop, persuaded me to put on some chest waders and spend an afternoon as a foreground to some photographs to accompany an article in 'The Times' to note the release of beavers in Knapdale. This is the site that was chosen for a trial release of beavers to Scotland.

At last, beavers have been released in Knapdale, some in the presence of Roseanna Cunningham, Minister for the Environment and other things such as forestry in the Scottish Government.





Yesterday, 30th May, I set off for my first solo canoeing journey of the year. I started at the Brigton, which is just below an unpleasant weir, and is now home to the Belmont Nursery, where people go and buy ornamental trees. A friendly mechanic said that it would be fine for me to set off from there in my canoe and leave my pickup in the car park. Unfortunaly, I left my GPS behind so I have little idea of where I took this photograph.

The water level was higher than the last couple of times I have canoed in the Isla, which, with the accompanying easterly wind, made it an easier paddle, though the water was shallow enough for it to be difficult to avoid grounding from time to time until the confluence with the Dean Water.

My original intention had been to canoe as far as the old Boat of Bardmony (a Boat in this sense was the Scots for a ferry, but the place has been bridged for quite a while now), but in the end I found myself paddling down to Isla Bridge, just before the confluence of the River Isla with the Tay. As I canoed I reflected on the suitability of these rivers for beavers. There were mute swans, bank martins, swallows, swifts, redshanks, sandpipers and some rather raucous warblers. I caught a glimpse of a kingfisher and saw several dippers, herons, but no osprey this time.





Sunday, 24 May 2009

Scent Mounds and Maternity Units




Peter Collen of the Marlab freshwater fisheries' research station at Pitlochry (http://www.marlab.ac.uk) came to see me on the 20th May. I had hoped that he was going to electro-fish in the stream. Unfortunately, he thought that the water was too turbid as a result of the recent rains, so he did no fishing. However, we walked the length of the water course that has been and is occupied by beavers.

Among many topics discussed, he asked if I had ever noticed any scent mounds. I had not, so far as I knew, but the next day after Peter's visit I noticed the powerful scent of beaver and, looking down, saw a piece of matted vegetation that had been left on the bank of the burn. I kneeled down to smell the object and breathed in the powerful scent of beaver.

Scent mounds are used by beavers to indicate to other beavers that they are occupying the territory. In the past I have noticed the scent of beavers from time to time, but this was the first time I have been able to place the scent. Beavers place these olfactory signal stations through their territories, where they serve as warnings, but also let other beavers know various bits of information about the beavers whose ground they are crossing, or sniffing from a distance.

To make a scent mound a beaver scrapes together some mud, or vegetation, places it on the bank of the stream and then, squatting over the mound squishes scent from its anal glands and castor sacs onto it.

The subject of beavers and their use of scent is a big one and anyone who is interested in it should refer to the work of Dietland Müller-Schwarze and Frank Rosell.



The second half of May is birth time for beaver kits. Last week a student from Edinburgh University, who is doing an MSc., came to sample water from the beaver stream in order to compare the chemistry of the water above and below the dams.

He came and asked me if beavers were often to be seen out by day. I replied that such a thing was unusual, though not impossible, so we went and looked and found the beaver in question, pretending not to be there. We left the site.

About two hours later I returned and found the beaver digging a burrow. I thought that this must be a female digging herself a burrow in which to give birth.

However, I had heard both that females find themselves a temporary home in which to give birth and that males are expelled from the main burrow and leave the female behind to give birth.

I checked with Bernard Richard's book 'Les Castors' (Balland 1980) and he writes «La femelle de son côté aménage l'abri où vont naître les jeunes, tandis que le mâle fait de même dans l'abri provisoire où il va passer quelques mois, d'avril à juillet environ».

'The female for her part arranges the shelter where the young will be born, while the male does the same in the temporary shelter where he will spend several months, from April to about July'.

Given that families of beavers often have a number of burrows and lodges within a territory the question of who moves and who stays is not as clear as if there were only one main lodge.

I wonder if anyone reading this blog has anything to suggest on the subject of who lives where during the time that the female gives birth.

Wednesday, 20 May 2009

More about Beavers





I strapped one of my trail cameras to a tree, overlooking this bit of shallow water where there are many bits of stripped wood. Unfortunately, I forgot to check the length of time that the video would run for. It defaulted to six seconds. But perhaps the beaver made off because it was disturbed by the pink glow of the infra-red as it was triggered by the animal? Any suggestions?




The photograph on the left shows the back of a beaver. She was very busy, digging a burrow in the bank of the ditch. I suspect that she is a female and is preparing a burrow in which to give birth to some kits. In the past I have been told variously that the female left the main lodge in order to give birth and that the female stayed in the main burrow and all the rest of the family left. I think that the first course of action is the more likely one - it tallies with my experience with sheep and cattle and I read somewhere long ago that women like to find a separate place in which to give birth. I wonder if anyone who reads this has an opinion to offer?










The downpours of rain of the last few days have raised the water level of the burn considerably and resulted in the development of new channels in the rebraiding of the burn, particularly as in these two photographs, below the middle dam.



Tuesday, 19 May 2009

Water Beetles





Garth Foster, who was here about a week ago, has sent me an account of his survey of the water beetles in the ponds. He found 23 different species, of which two were particularly notable.
The beetle on the left is Acilius canaliculatus. This is a first record for East Perthshire.

As you can see I have copied the photograph from a site on the Internet. I am grateful to biopix (www.biopix.dk) for this.




The waterbeetle on the left is the other one of special interest in our pond. It is called Donacia obscura. I am grateful to Josef Hlasek for the use of this photograph.

(http://www.hlasek.com)










There is a fair amount of Mare's Tail (Hippuris vulgaris) around the ponds.

Friday, 15 May 2009

A Wet Afternoon

Well, in fact, I took this photograph in the morning, but I liked this image, so here it is.

This is the pool created by the beavers' lowest dam along the Burnieshed Burn at Bamff after a day of heavy rain.







I walked out this afternoon to take a turn round the south side of the Big Pond and find somewhere for a Trail Camera to hang and photograph a beaver I had seen trying to eat stems of horsetail while swimming. I have seen this happening twice and it is a most endearing sight.


After fixing the camera to a tree trunk I walked on and found that the beavers had built a new lodge in the canal that joins the two ponds. It was six o'clock. A tail splashed and I realised that beavers were about. A few moments before taking this photograph I had noticed disturbance in the water to the right of me, but thought it could have been a mallard, or some other water fowl - there are little grebes and water hens about.





I walked back about fifty yards and realised that the beavers had built a long and very bendy dam to create a terrace, almost like a cultivation terrace, but holding back a pond, perhaps like a rice paddy. On top of this bit of the dam I found these hind paw prints of beaver.

By this time the rain was on again and I decided not to find my way through the swamp, but to go back by the way I had come, and then walk round by the north side of the ponds.





I was keen to photograph bog bean in flower.







Thursday, 14 May 2009

The Beaver's prehensile little finger





Away for a few days and one of the first things to be done on return is to check the trail cameras. I had left one strapped to a branch and looking down on a feeding station. The best of the clips shows this beaver stripping a branch. You can see the way it uses its little finger as a human would use a thumb very clearly.

This month has been rather cold. At least that is what the grass is telling us. The sheep are grazing fields in which the grass is very slow to grow. By the stream in the beaver territory, however, the grass is growing lush, even where the beaver have been grazing and creating their lawns. The rafts of sedge in the Big Pond, on the other hand, look very much grazed. Is this because there are more beavers there, or is it because of the cold and late growing season? Perhaps both are true?


I arrived back home in time to find Garth Foster, who had come to survey the water beetle population of the Big Pond ("An lochan beag uaine" to my Gaelic friends) busy at his task.

Professor Foster asked me if the beavers had made much difference to the pond since 2002.

The answer is that they have raised the water level by about fifty centimetres. They have cut and sculpted the rafts of sedge, increasing the area of water relative to the sedge. I think that there is rather less yellow iris and bog bean than there used to be, but impressions can be very misleading.

Further back in their enclosure, the beavers have swum up the ditches that were dug to drain the Norway Spruce and have dammed them to create shallow ponds. As a result of some windblow in the winter of 2007, more light is reaching these areas, so it will be interesting to see how the vegetation develops.



An exclosure that has survived since Kevin Jones erected it in 2003 is full of bog bean in
flower, but the bogbean round and about the exclosure is less thick and has fewer flowers.

The photo on the left shows some bogbean (Menyanthes trifoliata), which is about to flower. To the right of the bogbean are some stems of horsetail (Equisetum sp.) And what are the little blobs? Perhaps they are some kind of Lemna?



Here is a grazed over bit of sedge raft. Beavers can often be seen grazing on these areas in the evenings.











The last photograph was taken from the far side of the pond. In the foreground you can see some of the sedge raft that I have described with the channels of clear water on the shore side.

Tuesday, 5 May 2009

Some History - How did I become involved in this?

My practical interest in the restoration of wetlands began in 1981 when the remaining wet pasture to the west of Bamff House was drained along with a rushy bog.

Here is the pasture in question, looking east across the foreshortened damp/wet meadowland towards Bamff House.






My grieve (farm overseer) at that time, Jim Duncan, told me that he had caught sea trout in this ditch some time in the 1950s. The fact that this had happened in what seemed to me to be a drying out landscape impressed me enormously and I resolved to restore the lost wetlands at Bamff as much as I could.













Gradually it became possible to turn things round – drains were broken in the rushy bog and willows planted to choke those that remained. I was able to get a grant from the Forestry Commission in 1992 for the planting of woodland for conservation purposes. Grey and Eared Willow were planted as well as (by mistake) some Grey Alder and birch.


Then, sometime in the late ‘90s there came the prospect that beavers might return to Scotland.

The European Union's Habitats' Directive of 1986 had urged member states to look into the possibility of restoring species of animal and plant that had become extinct in their countries.

Scottish Natural Heritage investigated the possibilities and were keen to carry out a reintroduction. They launched a public consultation and conducted a public opinion survey that gave a favourable answer to the question put. Unfortunately, though, SNH had not taken enough account of the reactionary forces they would unleash.

Fearful that this worthwhile project would fail, some friends got together and called ourselves the Scottish Beaver Network. We thought, at first, that we should encourage SNH and try to help them. Then, we thought that we might bring some Eurasian beavers into the country ourselves, keep them in large enclosures, and show people how beavers interact with their environment.

In March 2002 the first beavers arrived here.




Sunday, 3 May 2009

A Dead Toad, Buzzard and Feeding Stations

As I walked past the middle dam along the Burnieshed Path, a buzzard lifted off. 'What have you left behind?' I wondered and wandered down to have a look. My mind had just turned to other things when I looked down and there, at my feet, lay this toad. The buzzard had stripped the left hind leg and was, no doubt, about to eat it when I had disturbed it. Clever of the buzzard to strip the unpleasant tasting skin of the toad.

According to a Norwegian paper about the diet of common buzzards in Southern Norway that I found through Google, buzzards do eat toads and frogs from time to time.





The photograph of the patch of grass to the left shows a beaver meadow by the burn. You can make out the cropped grass and the areas that the beavers have left untouched so far.











This photograph is of the same feeding station where the trail camera caught that short clip of a yearling beaver feeding and grooming itself.

Friday, 1 May 2009

Speculations about aspen regeneration and a beaver feeds.

Some years ago I read that the global distribution of the two species of beaver coincided with that of aspen (Populus spp.). I was reminded of this a few days ago. While browsing through two books I came across passages that described the very precise requirements cottonwood (Populus spp.) seeds have if they are to germinate. They need a particular fine silt, such as is left in the aftermath of spring floods and the time during which they are viable is very short.

I wonder if our aspen, which seems to have such difficulty in reproducing sexually here, is constrained by the same limitations as North American cottonwoods and if so, to what extent the absence of beavers in Scotland for some hundreds of years, coupled with all the changes to rivers (drains for agriculture, etc.) and land management (heavy grazing) have had in making it difficult for aspen to reproduce sexually.

This evening I went out to check one of my trail cameras. Here is one of the clips of film. A yearling (I guess) beaver is gnawing at a small branch, takes a break to groom itself and then goes back to feeding.