Tenerife Days: Beware of the Semi-Slugs

 

The sub-tropical cloud forest of Tenerife is known as the ‘laurisilva’ – the laurel woodland, and much of it feels like the grounds of a long-neglected British country house.  For the most part the ground is covered in dead leaves, but on the exposed earth of banks and tracks and on the windward side of tree trunks there is a rich growth of mosses.  Occasional crashings in the canopy are generally one of the two species of endemic laurel pigeons, bickering over laurel fruit while frequent rustlings in the undergrowth usually turn out to be blackbirds which are very common.  The dawn chorus in these mountain forests is truly wondrous in its richness and simplicity – the whole island seems to be ringing with the songs of countless blackbirds punctuated by the occasional grunts and squeaks of a roding woodcock.

As ever in the Canaries, there is a sense of strangeness that can be difficult to pin down, and when you do it is often what is not there that is at the root of it rather than what is.  On the forest floor, it finally dawned on me in December, there is a remarkable paucity of ants.  Not a total absence, but they do seem to be very scarce indeed. Grubbing about in the leaf litter and under dead wood produces plenty of non-ant life however – small crickets, cockroaches, earwigs, bristletails, millipedes, snails etc – all, no doubt, good food for blackbirds.  But the largest and most striking of the forest floor invertebrates are the semi-slugs.  These are 5-6cm long and, to my eye, have great charm as they cruise about in stately fashion and plain view.

What is a semi-slug?  Well, the snail body form, while clearly very successful, has several disadvantages.  You can’t go very fast while carrying a shell, and it also limits your ability to squeeze into confined spaces.  Hence a recurring theme in snail evolution has been trying to do without a shell i.e. becoming a slug.  Converting yourself from a snail to a slug requires radical internal reorganisation.  This can’t be done in a single step and evolution has left various partway stages scattered about the planet – from snails that are a little bit too big to withdraw entirely into their shells, through to slugs with a flake of shell hidden under the skin.  More or less halfway along the continuum are slugs that still carry a recognisable but absurdly small shell on their backs (or you could say snails with absurdly large bodies for their shells).  These are the semi-slugs.  Tenerife has several species, although all the semi-slugs I have seen there have looked very similar – with slender chocolate-brown bodies and a small, somewhat flattened amber-coloured shell halfway along the body and largely covered by flaps of skin. The shell sits at a stylish angle so that it looks as though the semi-slug is wearing a beret.

Semi-slug

The area of laurisilva I was exploring in December (the Monte del Agua) has a vehicle track running through it, unsurfaced but excellent for spotting semi-slugs and I soon came across two of them engrossed in eating something.  What they were eating appeared to be another semi-slug, but I have always assumed that slugs and snails were essentially vegetarian and, bearing in mind the bizarreness of their sex lives and sex organs, I thought I might be mistaken and crouched down for a closer look.  It still looked like two semi-slugs eating a third, but to be quite sure I picked one up and moved it to one side.  Yes, it was definitely a case of cannibalism.  This was interesting enough, but what followed was even more so.  The one I had moved slid back to resume its meal and as it did so it touched tentacles with the other diner. This one, which happened to be considerably smaller, then appeared to shoot out its mouthparts at the other one which recoiled as if stung, turned away and slid off at considerable (by mollusc standards) speed.  I had been thinking that what I was seeing was cannibalistic scavenging of a semi-slug that had got crushed by one of the occasional landrovers using the track, but this made me wonder if they might actually be cannibalistic predators.  Leaving the forest that evening I came across two more semi-slugs sharing a meal – a large chicken dropping.  So although my Tenerife ‘bible’ (the ‘Natural History of Tenerife’ by the inspirational Philip and Myrtle Ashmole) said that they were leaf-eaters, it seemed that they must like a bit of animal protein as well.

Anyway, on my next visit to the laurisilva I engineered an encounter between two semi-slugs that had been innocently minding their own business, putting a fragment of cheese down beside one of them.  It soon got stuck in, so I then moved the other one close to the cheese.  This too appreciated my gift, and as you can see in the attached video clip they contentedly mumbled on their cheese reminding me of a pair of Asian small-clawed otters sharing a large fish. 

However I then removed the cheese and the second video clip shows what happened once they had touched tentacles.

Given the slowness with which they go about their everyday affairs I find the speed of the strike by the attacker quite startling as, indeed, is the speed and flexibility of the response of the victim, appearing as it does almost to turn around within its own body and speed away.  It made me wonder if they had some kind of stiletto in the mouthparts, or even if they might actually be venomous.  Anyway, I decided to be more cautious in my handling of them in future!

Subsequent on-line research has revealed more about these strange creatures, but also indicates that there is still a lot to learn about them.  Tenerife has several species of semi-slug, all in the family Vitrinidae and all now put in the genus Insulivitrina, but previously included in the genus Plutonia.  I have not found a key to enable me to identify the ones I was watching to species.  Nor have I found any mention of venomousness in any terrestrial slug or snail, but Insulivitrina and Plutonia do have particularly sharp and prominent spines on their ‘radulae’ (the gastropod tongue) and some authors think that they are primarily carnivorous, their main prey probably being earthworms.  I presume that like many true slugs they must be covered with a distasteful slime or the blackbirds would have long since driven them to extinction.  

I found a particularly interesting paper by German zoologist Bernhard Hausdorf exploring the biogeography of the Vitrinid semi-slugs.  It seems that the greatest variety of species is found in Central Europe, particularly in the high mountains, and that those that do live in the lowlands are mostly active in winter.  They are all rather small.  He thinks this is because they have been driven to such specialised ecological niches by the more highly evolved true slugs.  There are no indigenous true slugs on the Canaries, so when in the dim and distant past they were colonised by semi-slugs these had free rein to grow large and to occupy (or reoccupy) much warmer habitats than they could on the European mainland.  Inevitably, with the colonisation of the islands by humans and the introduction of agriculture, true slugs have now arrived.  As yet no one seems to be focussing on the threat this may pose to the semi-slugs – the main conservation concern has been to ensure that the laurisilva itself was not entirely destroyed taking the entire ecosystem and all its endemic species with it – but it is one to watch.

References:

Ashmole, P. and Ashmole, M. (2016) Natural History of Tenerife. Whittles.

Barker, G.M. (2004)  Natural enemies of terrestrial molluscs.  CABI.

Hausdorf, B. (2001)  Macroevolution in progress: competition between semislugs and slugs resulting in ecological displacement and release. Biol. J. Linn. Soc. 74: 387-395.

Tenerife Days: of Choughs and Chaffinches

As the last of the golden wych elm leaves settled on the woodland floor in the Blyth valley, the dank grey chill of late November sent me scuttling for an early winter reprieve in Tenerife.  Such a fascinating island for the naturalist and so easily reached from Britain.  All the sunseekers off to the bars and beaches of Los Cristianos and Playa de las Americas keep the travel costs down for those of us who are seeking the wilder side of the island.  Sometimes in the airport departure lounge there are other travellers in boots and walking gear and we exchange little smiles and nods, oddities like mackerel caught up in a shoal of herring.

 There can surely be few places in the world that pack as much variety into such a small space as Tenerife manages to.  The largest of the Canary Islands, it is a bit smaller than the island of Lewis and Harris in the Hebrides (perhaps not a hugely helpful comparison as I am certain that many more Brits, and indeed many more Scots, will have been to Tenerife than have ever been to the Outer Hebrides, so let’s say it’s about the same size as County Durham) and it is staggeringly mountainous with the volcanic cone of Mount Teide soaring to almost 4000m at its heart, and a great ridge of mountains with stupendous cliffs dividing the island into two halves with completely different climates. 

Sunrise over Tenerife

The moist trade winds hit the north-west side of the mountains brewing up clouds that keep them green and verdant, while the south-east side bakes in the rain-shadow.  You can walk over the crest of the ridge from shadowy, evergreen, subtropical cloud forest

In the Cloud Forest

to dry stony semi-desert with Euphorbias and other weird and wonderful succulents in a matter of minutes;

Semi-desert in springtime

while just a few km away, via woodland of tree-heather and (largely overgrown) farmland,

Abandoned farmland

are fragrant pine forests;

The Zen garden simplicity of pine forest on volcanic ash

and a few more take you onto the stark lava fields of Teide itself studded with brooms and the giant 2m tall flower-spikes of Tajinaste Echium wildpreti (related to Vipers Bugloss). 

The lava fields

Truly Tenerife is a pocket continent.

 At their closest the Canaries are only 100km from the coast of Morocco, and like North Africa itself they belong, biogeographically, firmly to the Palaearctic rather than the Ethiopean realm.  The remarkable thing is just how many endemic species and subspecies they support given this proximity to the continental landmass.  But then that is one of the fascinations of islands.  The mix of species they end up with seems so random, and the extent to which the ones that do colonise then diverge in their characteristics from their congeners on the mainland seems utterly unpredictable.  Take the birds.  The avifauna of the Canaries is, basically, a rather limited subset of widespread Eurasian species.  But why is it, given how many Palaearctic migrants turn up there en route between Europe and Africa, that so few have established resident populations?  And why is the Blue Tit the only tit that has made it there, and why is it so gloriously, deeply blue in comparison with its anaemic European cousins?  

Tenerife Blue Tit – photo by Conry

The Red-Billed Chough Pyrrhocorax pyrrhocorax has made it across from the Atlas Mountains of Morocco but is to be found only on the island of La Palma (essentially a smaller version of Tenerife) where it swaggers about in true chough style in large flocks.

Choughs – photo by lapalmabirds.blogspot


  Tenerife is clearly visible from La Palma, 85km away, but there are no living choughs there now, although sub-fossil bones found in caves tell us that there used to be.  Choughs are more than capable of sea-crossings – witness their recolonisation of Cornwall from Wales in 2002 (just in time to pre-empt a reintroduction project!) and have also been shown to move between Brittany and Britain.

Chough flock over La Palma

The distances involved are much the same as those between the different Canary Islands so what is stopping them?

I spent quite a bit of time last week looking for Blue Chaffinches.  Unlike its Blue Tits, which are a single species found wherever there are trees and bushes, Tenerife’s chaffinches have split into two – a normal (albeit darker than ours) generalist chaffinch Fringilla coelebs canariensis,

Tenerife Chaffinch – photo by Paul Floyd
Blue Chaffinch – photo by Steve Lane

and the dusky blue-grey Blue Chaffinch Fringilla teydea that has evolved a rather chunkier bill.  This is found only in the pine forests and is said to feed primarily on the seeds of the endemic Canary Pine Pinus canariensis.  I have no doubt they do, although the ones I managed to watch were hunting for the seeds of Codeso Adenocarpus foliolosus (a leguminous shrub endemic to the Canaries) on the forest floor or fly-catching in the canopy.  Anyway it has found a niche for itself that has led to its divergence from the other chaffinches of the island.  But I wonder how secure that niche is?  Greenfinches Carduelis chloris have colonised Tenerife within the last fifty years and I saw one in the pine forest looking quite at home.  And what of those pine cone specialists par excellence, the crossbills Loxia sp?  They seem to be capable of evolving rapidly to tackle different conifer species and new situations (the Scottish Crossbill Loxia scotica has developed as a separate species within the last ten thousand years), are notoriously irruptive and live just across the water from the Canaries in the Atlas Mountains.  How long can it be before they make it over?

So much to ponder!

On the Autumn Symphony of 2018 and the Revival of the Wych Elm

No two autumns are exactly alike, and maybe no two person’s either – much depends on where you live and where you went – but for me this one has been very distinctive – a lovely, long, slow-moving symphony of an autumn.  The first movement opened on the Lake District fells in early September when already the deer-grass and the cotton-grass were beginning to turn (every stem banded with subtle colours), patches of bracken were turning tawny, and yellows, scarlets and coppers were appearing among the leaves of the bilberries (which fruited so early this year).

Ennerdale – the First Movement begins

Mid-September on the fringes of the Highlands in Perthshire saw the gold of the turning birches joining the expanding palette of the bracken and the sedges.

Perthshire  (note dead birches drowned by beavers)

By late September the leaves of brambles and rosebay in lowland Northumberland were beginning to glow as crimson as the heavily-berried hawthorns, and the hills were all in russet.

The second and third movements in October were unusual – the arrangement of the instruments atypical, with some stalwarts making only a brief contribution this year and some lesser contributors thrusting themselves forward for attention.  For a glorious week early in the month the country lanes were incandescent with the greeny gold of ash, which disappeared almost overnight so the naked trees loomed there like a memento mori as the other players took their turns.

A lane of Ash – like driving through a crisp white wine

That was the second movement.  After a long dry summer like this, the Swedish whitebeams (much loved by local authorities in Northumberland as street trees and for pit-heap reclamation schemes) normally give a few days of golden glory, lighting up even the dourest of council estates.  This year they and the rowans were stripped of most of their leaves by tree-toppling and branch-felling gales that ripped through Northumberland in late September and so could make no more than a token effort.  Many of those other landscaping stalwarts, the Norway maples, suffered the same fate, although some did contribute their New England scarlet right through the month – one of the advantages of having a tree flora with cultivars and varieties from many places is the phenological variation they bring.  Thus, most of the limes (all hybrids in this part of the world) flared and faded quite early in October, while others were still making brave contributions well into November.  However beech and birch, reliable as ever, played their parts right through this mellow third movement while never giving us the dramatic heights they are capable of.

So I thought we were set up for a slow, fading fourth movement in November.  But no, this autumn saved its best for last.  Almost overnight it seemed that every remaining leaf on every broadleaved tree and shrub burst into an effulgence of golds and yellows and ambers.

The view from my study – how am I supposed to concentrate!

Species that are normally only minor players in the autumn symphony were given their chance to shine in a glorious finale and took it in style.  Wych elm, sallow, hazel and hornbeam lit up the woods, glowing on the foggiest of days as if lit from within.

Wych Elm

Goat Willow

Hornbeam

Decked out in gold as they were, it made me appreciate just how significant a part wych elms still play in the ancient valley woodlands of Northumberland.  In the 1960s and ‘70s we had fears that Dutch Elm Disease was going to erase all the elms from the British landscape.  The disease did have a big impact of course, although not as severe a one up here as it did in southern Britain.  This was because the southern elms were clonal species, and in many areas suckering elm clones were the main hedgerow trees, and once one died the rest were sure to follow.  Wych elm, on the other hand, relies on sexual reproduction.  Also, it is more of a woodland than a hedgerow tree, so although it was far and away the commonest elm in the north, it wasn’t as prominent in our landscapes. Nevertheless, the big open-grown wych elms we did have all disappeared. There used to be two monsters close by where I grew up, and one of the signs of spring was when the flowers turned their great spreading crowns bruise-purple in March.  Each had a mass of epicormics twigs like a gigantic bird’s nests at its base, tempting places to hide in when playing hide-and-seek, but not wise ones if you were wearing shorts – books hardly ever tell you this, but elm leaves sting, not as much as nettles but it’s not pleasant when they get you on the tender skin behind the knees.

Wych Elm leaves – not quite as innocent as they look

In the Blyth valley woodlands wych elm was one of the commonest trees, many of them coppiced long before, and after a slow start Dutch elm disease ripped through these in the ‘80s leaving the valley sides dominated by stark crowns of dead stems.  In the part of the valley that is included within the Plessey Woods Country Park there were, of course, safety fears, so many of these wych elms were felled.  Then, panicking at the spectre of their woodland turning into a perpetual bramble thicket, the County Council decided to replace the wych elms with new trees, and so out came the tree tubes.  Many of their ash, oak and beech occupants, now ten or more metres tall, are still sporting their split and tattered tuley tube jackets, like Incredible Hulks on a rampage.

Grrr – let me out!

The wych elms did not, as it happens, die.  Generally Dutch elm disease prunes its victims back to the base rather than killing them, and in a little while new stems thrust up towards the sunlight.  Many of these new stems were cut back in their turn once their bark was thick enough to host the beetles that spread the fungus that causes the disease.  However as the years have gone by more and more of these stems seem to be getting away with it – just how many was brought home to me by this year’s late autumn colours.  Once more the multiple stems of the wych elms are a major feature of the Blyth valley woodlands, albeit as yet much skinnier than before.   Together with the ash, oak and beech (both planted and self-sown) they have suppressed the brambles in the country park, and elsewhere in the valley they fight it out with the hazel for the honour of being the principal component of the understorey shrub layer.  Some are even in the process of becoming decent sized trees once more.  It is good to see such resilience.

In the Wych Wood

Getting the best from Beavers – what kind of protection do they need?

On 24th November 2016 Roseanna Cunningham, the Scotland Environment Secretary, announced that the Scottish Government was minded to allow the established populations of reintroduced free-living beavers (Castor fiber) to remain, and to add beavers to the list of European Protected Species (EPS) and hence subject to the strict protection measures afforded by the Habitats Directive.  Cue much rejoicing on the part of nature conservation bodies and wildlife enthusiasts.  ‘This milestone moment’ said the Scottish Wildlife Trust (SWT).  ‘A landmark decision’ said RSPB Scotland.

For myself, though, the feelings were mixed.  Not because I do not want to see beavers back as part of the British fauna – I do, I think it’s great, they have much to offer the ecology of this country and I look forward to being able to watch them going about their business here as I have had the pleasure of doing in North America.  No, my concern was over the assumption that making them a European Protected Species is desirable or necessary for their protection and management.

Still, it was a milestone moment.  Nobody could say that the official approach to beaver reintroduction in Scotland has been rushed.  Scottish Natural Heritage (SNH) started consultations on the possibility in 1995, but it was not until 2009 that an official trial was set up in Knapdale, a remote part of the West Highlands, chosen because it would not be easy for the beavers to spread naturally from there into the rest of Scotland and thus would allow them to be rounded up again if it was decided not to proceed further.

In the meantime, however, it emerged that persons unknown had been releasing beavers (or allowing them to escape) into the catchment of the mighty Tay, Britain’s largest river system.  Apart from occupying a substantial part of Scotland, the Tay system embraces the full spectrum of habitats that Scotland has to offer from treeless mountains and uplands to some of the finest and most extensive and luxuriant woodlands and forests, many lochs, rich agricultural land and two cities (Perth and Dundee) as well as numerous towns and villages.  The beaver population was estimated at 146 in 2012 and subsequent studies have shown that it is continuing to grow and expand.  Population densities are highest on the Earn and the Isla – tributary rivers with good farmland catchments.

(https://www.nature.scot/sites/default/files/2017-07/A1608732%20-%20Tayside%20Beaver%20Study%20Group%20Final%20Report%202015%232.pdf)

It was on the Tay, at Birnam, that I attended an excellent two-day training course in beaver ecology and management last September run by Roisin Campbell-Palmer.  Roisin has been working with reintroduced beavers for years – at Knapdale, on the Tay and elsewhere – and really knows her stuff.  During the first part of the course we learned many things about the behaviour and ecology of beavers, including why they build dams (to ensure they always have water to retreat to when accessing their plant food and to ensure they have an underwater entrance to their lodges) and key aspects of their social life (they are devoted to family, intensely territorial, and as violent as mafiosi in defence of these).  After lunch we went to look for beaver field signs, but not in the kind of secluded Highland environment I was expecting.

‘We’ll drive down to Perth’, said Roisin, ‘Park outside Marks and Spencer’s and walk from there.’

And so it was beside the cyclepath on the northern edge of Perth, near the confluence of the River Almond with the Tay, that we were familiarised with the main signs of beaver activity – felled tree stumps and bark-stripped twigs and branches.  It also brought home to us that beavers are quite happy to move into towns.

Beaver-felled tree

The distinctive nibblings of Beavers

Later that day, a damp and gloomy evening, having established that the dog-walkers of Birnam and Dunkeld not infrequently see beavers, I spent some time on the leafy banks of the Tay itself.  Birnam is famous for two ancient trees – the Birnam Oak and the Birnam Sycamore – which sit on the edge of the willow thickets that fringe the river.  It is thought that the Birnam Oak could be as much as 600 years old, and if so then it is entirely possible that beavers swam past its roots when it was a youngster – and maybe even eyed it up as lodge-construction material.  The river backwaters nearby were all bobbing with stark white beaver-stripped twigs, but I think the Oak is big enough now to be safely beyond the reach of even the most ambitious beaver!

The Birnam Oak – should be safe from beavers by now!

On the second day we looked more closely at the management issues beavers pose – which essentially fall into two categories.  Firstly, there is the felling of trees we would rather they didn’t in our gardens and orchards – relatively easily mitigated by deterrent fencing and bark treatments – but it can make them unwelcome neighbours for keen suburban gardeners as we saw in the little town of Bridge of Earn.  Secondly there is the damming of drains, culverts and ditches.  This is a much greater challenge.  Yes, holding back and slowing the flow of water and creating new ponds and wetlands can help to alleviate flooding and the run-off of excessive nutrients.  But the beavers do not always block the watercourses we would like them to.  Our roads, sewers, housing and agriculture only work properly if we can manage water levels and water flows in, around, under or through them, and this does not fit comfortably with the beaver’s agenda of maximising wetness at every opportunity.  Like us, they are creatures that modify their environment to suit themselves, and it is going to be a real challenge to accommodate their needs alongside ours in our heavily modified and intensively used land.

Roisin and trainees in Bridge of Earn

Still, this is a challenge we are going to have to rise to, whether we like it or not.  It was very gracious of the Scottish Government to announce that beavers could stay – but it was a bit like saying the stable door could now be left open after the horses had all galloped off down the lane.  Practically and politically it would be incredibly difficult, maybe even impossible, to round up all the Tay beavers now, and given time they will, inexorably, colonise the whole of Britain.

Beaver lodges can be surprisingly inconspicuous

Given the challenges they pose, what sort of legal underpinning do we really need to ensure that we can manage our burgeoning beaver population effectively and humanely?  The Habitats Directive says that member states should consider reintroducing species formerly present in order to further their conservation, and the Scottish Government has concluded that since beavers were formerly present in Britain, and since they are on Annex IV of the Directive (the list of species in need of strict protection), then it is obliged to apply the strict protection provisions of Article 12 of the Directive to them.

However, as I have been saying for many years (e.g. Watson, 2008 & 2013), the problem with Article 12 of the Habitats Directive is that it is couched in terms of protecting individuals rather than populations of a species.  This might seem an obvious, indeed essential, thing to do, but in reality, by increasing the cost of avoiding potential disturbance and incidental killing of a few individuals, and by making the hosting of the species on your property a vexatious and sometimes onerous responsibility, it can be counter-productive.  For example, in the case of Great Crested Newts (Triturus cristatus) it can lead to the neglect and silting up of their breeding ponds (the biggest threat to their populations but allowing the newts to die out through natural processes is not an offence) and discourage the creation of new ones; and in the case of bats it can discourage the incorporation of roosting features into newer more energy-efficient (i.e. with fewer holes and gaps!) buildings.

Great Crested Newt – strictly protected and millions spent every year on it, but are its overall numbers increasing or decreasing?

In thinking about how best to manage the recolonisation of Britain by beavers it is worth considering some of the species that almost went extinct in Britain, and which have now come back from the brink.  In my post on seals (https://hughwatson.net/2018/01/11/of-singing-seals-and-drones/) I noted how the British population of Grey Seals (Halichoerus grypus) was possibly as low as 500 animals in 1914 when the first Grey Seals protection legislation was passed.  This did not outlaw the killing of seals entirely, it just set a close season for their killing which in effect protected them at their breeding sites, and banned some of the more barbaric killing methods then in use (e.g. the setting of giant, barbed iron spikes at haul-out sites).  That was all that was needed, and a hundred years later the British population is estimated at 150,000 and rising.

Grey Seal – with limited legal protection increased from 500 to 150,000 in a century

Another species that has returned from the brink of extinction without the need for anything other than minimal protective legislation is the Roe Deer (Capreolus capreolus).  This very nearly went the way of the Beaver and the Wolf.  By the late 1700s, when the deforestation of Britain had left us at the most treeless stage of our current interglacial history, the only place in Britain where these little woodland deer were to be found was in the remoter parts of the Scottish Highlands.  Their fortunes only started to revive in the 1800s with the rise of plantation woodlands, first on private estates then, in the 1900s, with the spread of the Forestry Commission’s industrial plantations.  If it hadn’t been for these land-use changes, we might well have been sitting around today arguing the merits of reintroducing Roe Deer to Britain.  Instead, with expansion of the relict native population from the north and a couple of nineteenth century reintroductions of stock from mainland Europe into southern England (there’s nothing new about reintroductions!), the British population has boomed.  It was estimated at 500,000 in 1995 (Harris, 1995) and it will be considerably higher now.  This was achieved without any form of protective legislation (indeed roe are regarded as silvicultural and agricultural pests) other than, latterly, the imposition of close seasons for their hunting and the banning of certain methods of killing.

Roe Deer by @JacquiMair – from almost extinct to half a million in 200 years, again with minimal legal protection

Polecats (Mustela putorius) are the latest species to boom, and are currently spreading rapidly through the English Midlands from their Welsh refuge, again without benefit of strict protection.

Polecat by @RichardBowler1 – range and numbers increasing without legal protection

To me this is good evidence that strict protection of individuals is generally irrelevant to the prospects of reintroduced and recovering populations of mammals.  Not only unnecessary but also a positive hindrance, as can be seen if we look at the management of beaver reintroductions in different European countries.  One country that is endeavouring to apply the Article 12 provisions to beavers is Germany, in particular the state of Bavaria.  Beavers were reintroduced into Bavaria, which is slightly smaller in area than Scotland, in the 1960s, and by 2012 the population was estimated to be in the range of 12,000 – 15,000 and still growing.  Management of beaver issues is undertaken by two full-time beaver consultants and a network of about 200 volunteers.  This level of reliance on volunteers brings the cost to the public purse (estimated at about 1 million Euros per year) down enormously.  A lot of effort goes into finding ways of accommodating the beavers but there is an acceptance that some have to be removed because of the level of effect they are having on human health, safety and economic wellbeing.  In earlier days many of these were live-trapped and relocated, but there are now many more beavers needing to be rehomed than there are places willing to accept them, so increasing numbers are having to be culled (700-800 in 2011).  Although the killing of strictly protected species is permissible as a last resort, it has to be justified and reported on, and there is uncertainty over the legality of this management system, and an awareness that an adverse ruling from the European Court of Justice could bring it crashing down.

Scottish Natural Heritage commissioned Aylwin Pillai of Aberdeen University’s Rural Law Research Group to review various approaches to dealing with situations where protected species come into conflict with human activities and she reported in 2012:(http://www.snh.org.uk/pdfs/publications/commissioned_reports/524.pdf).

With regard to the Bavarian beaver management system she said: ‘Although the system has led to a reduction in conflicts and has continued to allow the beaver to thrive it is open to criticism for being expensive and overly bureaucratic’.

Further:  ‘Our interviews suggest that this strategy allows for the swift and effective implementation of derogations and results in the death of 5% of the beaver population each year. Although this additional mortality clearly does not affect the level of population growth in Bavaria it does highlight that, once a beaver population establishes itself, the regular use of lethal methods may be needed.

And, in relation to Norway which is, of course, not a member of the EU:   ‘In Norway, where beaver management is not subject to the constraints of the Habitats Directive, problem beavers can be dealt with either by hunting in the open season or by applying for a licence in the closed season. Conflicts between conservationists and land owners or users over beavers appear to exist rarely in Norway. As effective legal management options are available to land owners for the control of beavers on their land this reduces animosity between land owners and government and diminishes the view that outside authorities are imposing restrictive burdens on local communities. It is believed very few beavers are illegally killed in Norway because of the accessibility of legal management options. ……

She concludes:  ‘These case studies suggest that an effective way of managing future problems and conflicts of interest in relation to the Eurasian Beaver may be to involve both landowners and the state in designing an inexpensive and non-bureaucratic, legally compliant programme for dealing with problems as and when they arise.’

I am bound to say that given the Article 12 restrictions this suggestion seems pie in the sky, and I find it difficult to see how the Scottish Beaver Forum, a working group attempting to come up with just such a system, will do any better than the Bavarians.

Beaver by @IanHayWildlife

Given the Brexit vote, and the assumption that all parts of the UK will be leaving the EU in due course, one does wonder if it is entirely necessary to be so punctilious about applying the letter of a law that will probably be open to unilateral revision in a few years’ time anyway.  But I don’t want get into the intra-EU and intra-UK politics of the situation.  What I would point out is that there may be a way of achieving a Norwegian-type solution while still complying with the Habitats Directive.

There is already at least one EU member state which is doing just that – Sweden.  Along with several other countries that already had thriving beaver populations when they first joined the EU, Sweden secured an opt-out from applying Article 12 to its beavers.  Instead Sweden agreed that its beavers would be listed on Annex V of the Habitats Directive.  Annex V species are ones whose conservation status must be kept under surveillance and whose taking and exploitation may need to be controlled if this is threatened.  The framework for these controls is set out in Articles 14 and 15 of the Directive.  It is rarely appreciated in the UK that the Habitats Directive recognises this second category of protected species, a situation not helped by the term ‘European Protected Species’ being applied only to the ‘strictly protected’ Annex  IV species in the UK’s Habitats Regulations (the legislation which turns the European Habitats Directive into UK law).

I asked Goran Hartman, the authority on the beaver’s recolonisation of Sweden, how well the Swedish management model, based on close seasons for killing and restrictions on the methods used for this, was working in practice.

He replied:  ‘I would say that this system works fairly well. I believe that the main reason is because landowners are given tools to handle wildlife damages. Like many other species landowners become aggressive when they are trapped, and I can understand them. In areas with increasing beaver populations but not yet any possibilities to hunt beavers there were loud complaints but as soon as they were given rights to hunt the complaints stopped. It was now up to them to do something about the problems, within the given legal framework. This seldom stopped the beaver population from increasing as beaver hunting is time consuming and other wildlife damage (e.g. moose and wild boar) is more in focus. Farmers and forest owners have many problems and beaver damage is seldom one of the bigger.

So, for Heaven’s sake, let’s learn from our Scandinavian cousins who are so far ahead of us in beaver conservation.  What I suggest our government(s) should be doing if they wish to stay within the Habitats Directive framework is to say to the European Commission that either:

(a) it should move the beaver from Annex IV to Annex V as there are now well over a million of them worldwide and according to IUCN (the International Union for the Conservation of Nature) it is a species of ‘Least Concern’ – ‘If current trends continue, the Eurasian Beaver will be a fairly common mammal in much of Europe within the next few decades’ (http://www.iucnredlist.org/details/4007/0).  I imagine there would be considerable support from other EU countries for this.  Or alternatively:

(b) since the reintroduction of beavers to Britain is irrelevant to the conservation of the booming global beaver population, the UK should be added to the list of countries in which beaver is included in Annex V rather than Annex IV.  If they are on Annex V then the UK would still be required to maintain them at favourable conservation status, but it would allow much greater flexibility in how this could be done, with far less bureaucracy and cost to the taxpayer.

(It is interesting to note that in the 1982 Bern Convention [the Convention on the Conservation of European Wildlife and Natural Habitats], the international agreement which led (often word for word) in 1992 to the Habitats Directive, the beaver is included on the list of ‘protected fauna’ as opposed to the list of ‘strictly protected fauna’.  If anyone knows who or what caused this change of approach during that ten year interval I would be very interested to know.)

The Scottish Government has just (6th March) closed its public consultation on its beaver management strategy (https://consult.gov.scot/forestry/beavers-in-scotland/).  Much information was provided in the voluminous supporting documents e.g. an in many ways excellent report Beavers in Scotland from SNH, but the SEA (Strategic Environmental Assessment) based on these (also voluminous) is, in my view, an unsatisfactory document that fails to address the wider strategic issues and focusses instead on the impacts in the Knapdale area and the Tay catchment.  There is no consideration within it of legal options: the treatment of beavers as a strictly protected species under Article 12 is assumed.  I have been endeavouring since October, via formal Freedom of Information requests, to see the legal advice sought and received in respect of this decision, but this has been refused on the grounds that it would be detrimental to the abilities of ministers and their advisers to have candid discussions on the development of beaver policy and would breach the right to confidentiality of communications between legal advisers and their clients.  I do not accept this reasoning as valid, and will be appealing to the Scottish Information Commissioner but it is likely to be many months before an adjudication is forthcoming.  In the mean time, this post is my way of attempting to open up this aspect of beaver reintroduction to public debate.

Whichever legal route we end up following in order to manage our beavers, the lesson from Bavaria, from Sweden and from Norway is that we are going to have to cull some of them, and therein lies what may be our biggest problem – the psychological one.  The island of Great Britain is three times the size of Bavaria.  If we assume that our beaver population will boom as theirs has and that we end up with a similar density of beavers and similar management issues, then ultimately we are looking at having to cull perhaps 3000 beavers every year.  Are we, the animal-loving British public, ready for that?  Or are we just too squeamish to adapt sensibly to life with a thriving beaver population?

Young Beaver munching on Willow by @Lairy-Book

References:

Campbell-Palmer, R. et al (2015) The Eurasian Beaver. Exeter: Pelagic Publishing.

Harris, S. et al (1995) A review of British mammals: population estimates and conservation status of British mammals other than cetaceans. JNCC, Peterborough.

Hartman, G. (1994) Long-term population development of a reintroduced beaver (Castor fiber) population in Sweden. Cons. Biol. 8(3): 713-717.

Jones, S. et al (2013) The battle for British beavers. British Wildlife 24(6): 381-392.

Pillai, A. et al (2012) Derogations for protected species in European reintroductions.  Scottish Natural Heritage Commissioned Report no. 524.

Scottish Natural Heritage (2015)  Beavers in Scotland: a Report to the Scottish Government.

Tayside Beaver Study Group (2015)  Final Report.

Watson, H (2008) Great Crested Newts and their conservation: are we getting it all wrong?  In Practice – Bulletin of the Institute of Ecology and Environmental Management 60: 25-28.

Watson, H (2013) Better for man and better for beast – Bats, newts and Article 12(4) of the Habitats Directive.  In Practice – Bulletin of the Institute of Ecology and Environmental Management 80: 37-38.

Of Hawfinches and Karma

I grew up in Northumberland, next to an old WW2 army camp of Nissen huts and cheap brick buildings.  When I was very young some of the buildings were being used for rearing pigs – noisy porkers growing fat on the swill brewed up from school dinner leftovers, restaurant scrapings and stale bakery discards – ah, we knew how to make recycling work in those days!  However in due course the pig farm closed down and the buildings lay empty for several years while a rampant growth of hawthorns and elder bushes, fueled by years of copious manuring, sprang up around them. Checking inside for barn owl roosts one snowy winter’s day I noticed the silhouettes of birds feeding on the haws through the grimy cobwebbed windows, and then discovered that a broken pane meant I had a brilliant ready-made hide.  I found an old wooden chair and spent many happy hours watching throngs of thrushes – redwings and fieldfares as well as blackbirds, mistle and song thrushes – and other birds driven to the berries by the snow, at little more than arm’s length.  I have never been as close to fieldfares, so handsome and wary, before or since.  And then some birds turned up that I had never seen before – big chunky finches with massive bills and grumpy expressions.  They were subtly coloured in peach, cinnamon and apricot, their wings strikingly patterned and with a small patch of curiously shaped inky blue feathers; those bills framed in deep black making them look almost parrot or toucan-like, as if they would be more at home in a tropical rain forest.  They were Hawfinches (Coccothraustes coccothraustes).

The only other time I had seen hawfinches since then was one or two summers later when I came across a family party, adults and fledglings, in the Blyth Valley woodlands nearby.  This would have been about 1970 when hawfinches, which had been gradually increasing in distribution and abundance since the mid-1800s, were at the peak of their British fortunes. After about 1990, however, their expansion went into reverse for reasons not yet understood, and none have been known to breed in Northumberland since 2005.

Hawfinch by Brian Martin

So I was very interested when word on the birding grapevine reached me last November that there was a big influx of wintering hawfinches that were turning up all over Britain.  As with its decline as a breeding bird, there seems to be no consensus on what has produced this unusual irruption.  Hawfinches are widespread in continental Europe and there have been mutterings about forest fires in Portugal and a shortage of tree seeds in Eastern Europe, but no clear evidence offered for either of these hypotheses.  A twitter group has been set up to report sightings in Britain (@HawfinchesUK) which is well worth visiting if you want to find out whether there are any known to be near you.  Otherwise it is worth checking any stands of hornbeams, yews, cherries or other trees with large hard seeds – they could, literally, turn up anywhere with a suitable food source.

I was lucky to have some reported not far away from me at Abbey Mills on the outskirts of Morpeth.  Morpeth is a small (but rapidly expanding) market town, unwisely located where the valley of the River Wansbeck narrows as it cuts into the coastal plain.  This means it is prone to severe flooding but also that it is very richly endowed with ancient semi-natural woodlands on the steep valley sides of both the main river and its tributary burns (it is therefore entirely appropriate that William Turner, the 16th century ‘Father of English Botany’ not the fictional movie pirate, came from Morpeth).  However to my surprise the Abbey Mill hawfinches were not utilising these ancient woodlands but rather three rows of tall, spindly and tightly spaced hornbeams on the fields of the floodplain.  Hawfinches, with their massive seed-cracking bills, love hornbeam seeds so that they were making use of these trees was not the surprise; finding so many hornbeams planted on the outskirts of Morpeth was.  Hornbeam is not native this far north, and while you come across scattered planted and naturalised hornbeams in Northumberland I had never come across so many in one place.

Hawfinch by Brian Martin

I was pondering this while admiring the little flock of hawfinches that had taken up residence, and remarked on it to a birder called Duncan, a man well into his third age, who had been photographing the birds.

‘Ah’, he said, ‘I know the answer to that – I planted them!  This was a county council tree nursery back in the ‘60s and I worked here.  We planted those trees to make hedges to divide it up into compartments.  We didn’t know they were hornbeams – we thought we were planting beech !’

Duncan had come to birding relatively late in life and had never seen hawfinches before they turned up here on his doorstep.

Hawfinch on hornbeam by Brian Martin (@BrianSmyrTyr1)

It is nice to think something you do for one reason can have entirely unforeseen but beneficial results that give you such pleasure fifty years later – that, surely, has to be some kind of Karma!

Of Singing Seals and Drones

I have two bat detectors on the Farne Islands – one on Inner Farne and one on Brownsman – and visit them several times a year to download data and check that they are still working properly.  The Farnes change character remarkably during the course of the year, bursting with life during the seabird breeding season, then strangely quiet after the terns and auks head off in August until the following spring.  But some of the islands have a third facet to their character – these are the seal breeding islands, chief amongst which are Brownsman and its tidally conjoined twin Staple Island.  Come October, for about 3 months these become the domain of the Grey Seals (Halichoerus grypus).  The lush growth of guano-fertilised herbage that in the height of summer covers everything that isn’t bare rock or fresh puffin-excavation is relentlessly trampled out of existence by hundreds of lumbering seal bodies so that parts resemble nothing so much as a First World War battlefield.

Brownsman in November – trashed by seals

The seals boss the islands, and this presents challenges on the final visit of the year to Brownsman.  There are only a couple of places where you can land a boat and whichever you use you have to run a seal gauntlet to get to the cottage where the rangers live and where the detector is located.  Mother seals are very protective of their pups, and bull seals are suspicious of anything approaching their females so there is considerable scope for inter-species misunderstandings.

Bull Grey Seal, suspicious of my motives

Cow seal, likewise

Seal pups start off as little creamy-white scraps with over-large heads, but within a few days of intensive suckling they swell into chubby white rugby balls.  Once she has them fat enough (after about 18 days during which time they have ballooned from ~14 to ~45 kilos) the female abandons them.  The bull seals are constantly patrolling the colony, fighting each other, squashing pups and sexually harassing the females, and by the time she heads off the female will be carrying the fertilised egg that will develop into next year’s pup.

Grey Seals are much the same weight as lions with strength and teeth to match – if they had legs rather than flippers we would be terrified of them.

Reasons to be thankful that seals do not have legs

Fortunately sex and child-rearing take place on land, and once they are in the water they are much more chilled, their curiosity making them a delight to scuba divers and snorkelers.

Dive Buddy off the Farnes – Photo by Ben Burville @sealdiver

Having been abandoned by their mothers the pups proceed to moult into their mottled adult coats, and are particularly delightful at this stage.  I don’t know if it is a term in general use, but the Farnes rangers call them ‘moleys’, which is very apt.

Moleys

The moleys tend to drift together into loose groups, now and again galumphing around playfully, but mostly just snoozing away the grey days and long nights of early winter until after three or four weeks they head off to sea to start looking for food.  Now I started my professional career studying coastal-living otters in Shetland.  Otter cubs go to sea when they are about 2 months old but accompany their mothers for another year or so, and still struggle to survive when they finally have to fend for themselves.  It has therefore always intrigued me that Grey Seals are able to dispense entirely with parental education and support – in which respect they are more like fish or amphibians than mammals (and even some of those would put Grey Seals to shame!)  One would have thought that to begin with young Grey Seals would not venture far while they ‘find their flippers’, but far from it.  Geolocator tagging has shown that these babies promptly set off on what may be the widest wanderings of their lives.  Pups tagged on the Isle of May in the Firth of Forth fan out into the North Sea and have been found as far afield as Holland and Norway within a few weeks of setting out.  They forage primarily on the seabed and the whole of the North Sea, which is relatively shallow, is their oyster – one male pup was even recorded diving to over 200m in the Norwegian Trench.

For the pups, this is a desperate race against time that pits their ability to learn how, where and when to dive and catch fish against those dwindling fat reserves that are providing them with energy and keeping the cold at bay.  Mortality is high and when you look at this equation you wonder why the moleys don’t head off to sea as soon as possible rather than lolling around on land for the thick end of a month and losing up to a quarter of their body weight in the process.  However evolution would have long since winnowed out the lingering habit if there had not been a very good reason for it.  That reason seems to be that their bodies need this time to use a hefty chunk of that puppy fat to fuel the development of the physiological adaptations they will need for sustained swimming, diving and foraging – it is a sort of pupal stage where a fat, guzzling milksop goes in at one end and a young marine predator, its blood and muscles charged with oxygen-carrying haemoglobin and myoglobin, comes out at the other!

Who are you calling a pupa?!

We’re not being lazy, honest!

Busy metamorphosing into a top marine predator

Myoglobin dreams……

The Grey Seal is a species that is doing very well at present.  Numbers around Britain and Ireland were very low in the early 1900s, possibly even as low as 500 when the Grey Seals (Protection) Act was introduced in 1914.  One hundred years later, the population is estimated to be in the order of 150,000 and still growing.  The biggest breeding colonies were, and still are, in the Orkneys and the Outer Hebrides and for a long time the only breeding colony on the east coast of Britain was the one on the Farnes.  This continued to be the case until 1956 when the first pup was born on the Isle of May, but that colony didn’t really take off until the late 1970s.  Then in the late 1990s they started breeding on the mainland, on the little boulder beaches at the feet of the towering cliffs of the Berwickshire coast centred on Fast Castle Head.  Much more surprising was the establishment in the 1980s of a breeding colony at Donna Nook on the Lincolnshire coast as this was utterly different habitat – vast open sandy beaches readily accessible from land – and there are now two sandy beach colonies in Norfolk as well, at Blakeney Point and at Horsey.  Tagging and genetic studies have shown that the Farnes is the ultimate source of these new colonies, several of which are now producing more pups that the motherland, Fast Castle being the largest.  While the rate of population growth has slowed around the north and west of Britain, it continues exponentially on the east coast with about 13,000 pups produced in 2014.  With 7 pups born this year, it looks as if Coquet Island, 30km to the south of the Farnes, is becoming the next new breeding colony.

This development of the habit of making use of sandy shores for breeding is an interesting one, not least because it holds the potential for competition with Common Seals (Phoca vitulina) which traditionally have been much more strongly associated with sandbanks and estuaries that have Grey Seals.  Indeed there seems a strong likelihood that the crashes in numbers of Common Seals in the Wash area, caused by outbreaks of Phocine Distemper Disease that first struck in 1988, opened up the way south for the Greys.  Now, it seems, the habit of using sandy beaches for hauling out is spreading back north through the population.

I have to admit to a very soft spot for Common Seals.  They shared the same (rocky) coasts as the otters I was studying so I saw quite a lot of them during my Shetland years.  They have very friendly puppyish faces and are much more playful than their grey cousins, being given to leaping clear of the water, flipper-slapping, snorting and serial porpoising.  They will come a long way into estuaries, right into freshwater, and one fine May morning I watched one fishing upstream of Newcastle just below the tidal limit of the River Tyne at Wylam, some 25km from the sea as the crow flies (and considerably more as the seal swims) looking quite at home in between the lush green river banks, bedecked with Cow Parsley and Dame’s Violet.  Indeed I think the least far-fetched explanation for the existence of the Loch Ness Monster is that it is based on whisky-fuelled sightings of a convoy of porpoising Common Seals spotted through Highland drizzle on a murky night.  Although much more numerous than the Grey Seal in global terms, they are less common than Greys in British waters so their home-grown English name is not particularly appropriate.  Far better is their international English name of Harbour Seal, and that is what I will refer to them as hereafter.  In fact I think I will go one step further by adopting our American cousins’ spelling i.e. dropping that superfluo(u)s ‘u’ and referring to them as Harbor Seals.

Anyway, not so long ago (the 1990s), if I wanted to watch Harbor Seals I would head for the tidal island of Lindisfarne (aka Holy Island), just up the coast from the Farnes.  At low tide a dozen or two would haul out on the sandbanks which form a sort of Northumbrian mini-Wash between Lindisfarne and the mainland, and splosh and cavort in the channels.  By about 2010 this had become impossible.  Not necessarily because the Harbor Seals are no longer there, but because they have now been swamped by literally hundreds of Grey Seals with their newly acquired sandbank habit.  It would take powerful optics and greater patience than I have to establish whether the Harbor Seals have actually been displaced, or if they are still in there amongst the throngs of Greys.  Now when the wind is in the west the whole of Lindisfarne is pervaded by the singing of the Greys – a delightful experience when you are sitting in the warm sunshine in the sheltered gardens of one of the coffee shops in the village.  Close to, you realise that this wonderfully evocative sound is actually the incessant, cantankerous wailing of seals telling their neighbours to keep their distance (it has been well said that they are gregarious but not sociable), but distance strips away the harsh notes and leaves only the mournful keening to caress the ear and fill the imagination with mermaids and lost souls.  The Greys are also hauling out in their hundreds on the mainland close by, at the northern tip of Ross Back Sands, and it is surely only a matter of time before they start breeding there as well.

To return to the Farnes, the Grey Seal pup production has surged over the last few years, reaching 2,295 in 2016, and a large chunk of that surge has happened on Brownsman (934 pups in 2016).  With the result that the rangers decided they could no longer run the risk of my getting marooned up a ladder by seals, and so this autumn I was restricted to Inner Farne and the issuing of detailed instructions to the Brownsman landing party.  I am pleased to say, though, that I still got my seal pup fix as they are now beginning to use St Cuthbert’s Cove, the little sandy beach next to the jetty on Inner Farne.

One of the pleasures of visiting the Farnes is the opportunity to talk to various scientists about their research there and my visit in late November coincided with one by Bethany Cowan, a marine science student at Newcastle University.  The mortality rate of Grey Seal pups on the Farnes is considerably higher than at most other North Sea colonies, and while the most likely explanation for this is their level of exposure to storms which can wash hundreds of pups away if they hit at the wrong times, there is a nagging concern that some of it could be due to the disturbance caused to the seals by the pup monitoring process.  There are several counts during the course of the pupping season during which any new pups are sprayed with dye to avoid double-counting and to get an estimate of on-site mortality.  This has been the fundamental methodology used since the 1950s so clearly if there has been any adverse effect it has not been significant enough to interfere with the North Sea population explosion.  Nevertheless, it is a potential animal welfare even if not a conservation issue, and allied with concerns about the human health and safety risks of the process, the National Trust had decided to experiment with the use of a drone to count the pups from the air.  Bethany’s study is into how seals respond to this new source of potential disturbance.  Cue the drone man – Tim Askew, a filmmaker specialising in filming with drones.  The Inner Farne bat equipment safely decommissioned I spent a happy couple of hours peering over Tim’s shoulders at a kittiwake’s eye view of the islands and of the seals loafing and diving in the clear waters, and with Bethany watching the behaviour of the seal mothers and pups on the beach.  With the coming and going of boats at the jetty, the seals here seem thoroughly habituated to people so  it was a more relaxed environment for seal-watching than Brownsman and it is a much better place for studying how seals react to one another rather than to humans.  However I have to say that following the adventures of one little pup whose mother had sloped off to cool down in the sea as he flopped his wailing way from one female seal to another in quest of milk was quite harrowing – mother seals do not treat milk-poachers kindly!

Do you think she’ll let me have some too?

As far as I could tell the seals were, at most, just mildly curious about the drone – looking up at this buzzy little flying object above their heads.  This is not really surprising, given that they have to share the islands with thousands of racketing seabirds for several months each year.  It certainly looks to me like this will be a situation where new technology will prove its worth.

Bethany: ‘That one’s been suckling for 8 minutes now’

Tim and drone

Flying drones over the sea requires extra concentration!

Getting a drone’s eye view

As for the Grey Seals’ future, I can’t help but think these may be their salad days.  At present they are the top predator in the North Sea, but it has not always been so.  In other parts of their range they are preyed upon by Killer Whales (Orcinus orca).  Currently these are, at best, only occasional visitors to the North Sea, but surely the burgeoning biomass of Grey Seals is such that the Killers will not continue to overlook this opportunity for ever.  More immediately, I suspect Brexit will pose a threat to them.  Back in the ’60s and ’70s when seal numbers were only a tenth of what they are now, they were perceived as an economic threat by the fishing community and there were several somewhat ineffectual seal culls which foundered in the face of public opinion and scientific uncertainty.  Post-Brexit, if we ‘take back control’ of our seas and British fishermen no longer have foreign fishermen to blame for catches failing to live up to hopes and expectations, then I think we can confidently expect the seals to become the scapegoat of choice once more.

References

Anderson, S (1990) Seals. Whittet Books.

Bennett, K et al (2010) Effects of age and body mass on development of diving capabilities of gray seal pups: costs and benefits of the postweaning fast. Physiol. Biochem. Zool. 83(6): 911-923.

Carter, M et al (2017) Intrinsic and extrinsic factors drive ontogeny of early-life at-sea behaviour in a marine top predator. www.nature.com/scientificreports

Noren, S et al (2005) Development of the blood and muscle oxygen stores of gray seals (Halichoerus grypus): Implications for juvenile diving capacity and the necessity of a post-weaning fast. Physiol. Biochem. Zool. 78(4): 482-490.

Sleate, E and Perrow, M (2008) An undercurrent of change for Norfolk’s seals. British Wildlife 19(5), 305-314.

Smout, TC and Stewart, M (2012)  The Firth of Forth: an environmental history.  Birlinn.

Special Committee on Seals (SCOS) 2016 report: http://www.smru.st-andrews.ac.uk/files/2017/04/SCOS-2016.pdf

Tooth, E (2017) The Farne Islands grey seal colony in 2016. Northumbrian Naturalist 82, 92-95.

In Praise of the Pentax Papilio

Back in 2008 I was in search of a lightweight pair of binoculars to use on hill-walking and backpacking trips when carrying my big beautiful Swarovski 10x42s felt like too much of a neck-aching burden.  I tried out a number of models and having grumbled about their limitations, particularly their inability to focus on objects closer than about 3m, was eventually pointed in the direction of the Pentax Papilio (thank you Owain, blessed be thy name).  As their name suggests, these are aimed primarily at butterfly-watchers rather than birders, and they can focus down to about 50cm.  This makes them absolutely unique – effectively you have a combination of a conventional pair of binoculars and a low-powered binocular microscope that you can use to examine insects, flowers etc in detail without having to catch or pick them or crouch down in discomfort.  Moreover this in-depth observation can be done without disturbing small creatures.  It isn’t surprising really that the presence of a massive and potentially hostile object looming over it should have an inhibiting effect on the behaviour of your typical invertebrate.  However what did come as a revelation was the remarkably short distance one has to move back to release these inhibitions.  At 0.5 – 1.0m distance most invertebrates seem to have the self-confidence to ignore you as a potential threat.  I guess time is pressing, life is short and it isn’t worth wasting valuable minutes through stopping what you are doing when the world is full of massive objects most of which are indifferent to your existence and pose you no direct threat particularly if they keep still and, even if they move closer, can probably be evaded.  So, instead of freezing and trying to avoid drawing attention to themselves, these little creatures carry on with their normal activities – exploring, feeding, grooming, stalking, signalling, courting, egg-laying, fighting – and do so with energy, flexibility and character.  An undisturbed insect or spider has an expressiveness in the way it waggles its antennae, cocks its head, drums its feet etc that is hard to reconcile with the robotic, knight-in-armour rigidity it has when trying not to be noticed.  This is the magical world that the Pentax Papilio opens up.

The secret of its magic is that as you focus in on objects close to you the objective lenses move away from the eyepieces and move closer together, thus maintaining the stereo view.  The smoothness of this movement is ensured by housing the objective lenses within the body of the binoculars, protected from the outside world behind a single fixed oval sheet of plain glass.  If ever you have a spare moment, it is very satisfying to turn the Papilios around, play with the focus wheel and watch the slickness of this operation!

Apart from this, they also function as perfectly decent lightweight travel binoculars, and they are great for surveying aquatic mammals too as you can scrutinise pawprints and droppings without having to slither down risky riverbanks or contort yourself into undercut tree root plates and bankside cavities.

Papilios are available in two magnification – 6.5x and 8.5x. Normally I would think 6.5x was not powerful enough but given that the diameter of the objective lenses is only 21mm (small even by pocket binocular standards) I opted for these rather than the 8.5s because of concerns that the higher magnification would not give a bright enough image.

Earlier this year, one of my nearest and dearest expressed an interest in having a pair of Papilios for herself, so I went back to the Internet to check out current prices.  At £66 my Papilios had been an absolute snip in 2008, but prices have doubled since then.  However Pentax were also claiming advances in the construction sufficient to justify badging them as Papilio IIs.  The main difference seemed to be that all the lenses were now multi-coated.  I am no optics nerd, but I gather that the practical implication of this is that the image should be brighter and clearer.  Given the slickness of Amazon’s return procedures these days, I ordered both the 6.5s and the 8.5s so I could try them against each other.  The 8.5s were noticeably more powerful and gave a more detailed image at distance and, in very good light, at close range also.  However I felt that at close range in anything other than very good light, the 6.5s had the edge as the greater brightness of their image more than offset the lower magnification.  There was less difference in the width of the field of view than I would have expected, but it did seem as if the depth of field of the 8.5s was slightly less than that of the 6.5s so it was a little trickier to keep them in sharpest focus.  Ultimately then, while I felt I would be happy with either model, I plumped for the 6.5s again because so much of my use is likely to be in less than ideal light – the gloom of cloudy Britain or of dawn, dusk and overhangs.  If I was living in sunnier climes I would probably go for the 8.5s.

The Papilio IIs were noticeably brighter and seemed sharper than the original Papilios, so I hoped my nearest and dearest would be happy with my well-loved used pair while I relished the new ones (she was!)

Two pairs of bins!

(PS Amazon’s returns procedure wasn’t that slick after all – initially they refunded me for the slightly cheaper 6.5s I had kept, not the 8.5s I had sent back!  Also, at the time of this re-posting, there are some available on-line for just under £100 – grab ’em quick!).

Zombies and Uninvited Guests: Who Would be a Wood Ant?

Naturalists are lucky people.  Our worlds are full of wonders and we can find magic under our noses wherever we are.

In September I paid my old friends Gus and Tess a visit.  They live in Speyside amongst the magnificence of the old Caledonian pine forests.  Gus is a zoologist by training, and Tess a botanist, but both are naturalists of wide interests and experience.  The evening I arrived Gus had just returned from an outing with an ant expert to search for a creature called the Shining Guest Ant, and as both Tess and I were keen to benefit from his new knowledge we went out to look for it the next day.

The nests of Wood Ants (Formica sp) are a conspicuous feature of the pine forests, mounds of fallen pine needles forever patrolled by their makers.  They are also an attractive source of food and security for other organisms that can cope with the massed throngs of formic-acid-squirting and pincer-jawed inhabitants, and amongst these other organisms are the Shining Guest Ants (Formicoxenus nitidulus).

It was a cool grey day, not very promising, but with Gus’s newly acquired knowledge we soon found an appropriately located nest and crouched down to scrutinise the ants moving about on its surface.  However the first ant that drew my attention was an unnaturally static one.  Courtesy of my extremely close-focussing Pentax Papilio binoculars (there is more about these in a post I will bring across from LinkedIn) I could see that it was frozen in an odd position, with its jaws clamped firmly to a dead grass stem protruding from the nest.  Gus diagnosed its problem as a fungal infection – there is a genus of parasitic fungi, Cordyceps, that specialises in feeding on the innards of ants.  In order to spread from ant to ant it has evolved the fiendish technique of infecting the ant’s brain so that is impelled to climb up a twig or grass stem, bite down hard then die, firmly fixed in place.

Zombie Wood Ant – photo by Gus Jones

Shortly thereafter the fruiting body of the fungus bursts forth from the head of the ant to scatter its spores on the ground below where its sisters are scuttling about and so get infected in their turn.  Give me athlete’s foot any day!

Further diligent searching revealed several Shining Guest Ants.  They were not easy to pick out at first, but once spotted were readily distinguished.  They are much smaller than the wood ants and quite differently proportioned – longer-bodied and shorter-legged – as well as having distinctively glossy amber-coloured bodies.  They showed up best when wandering across the golden birch leaves that had fallen on the nest.

Wood Ant and Guest – photo by Gus Jones

Unlike some other members of their genus which are duller in colour and rely on going undetected by mimicking the scent of their hosts, Shining Guest Ants have been found to secrete a substance that is sufficiently repulsive to make the wood ants drop them after grabbing them – something that happened quite frequently.  I wonder too, if the Shining Guest Ant’s extreme glossiness has a part to play in this, perhaps reflecting a cuticle strengthened to resist repeated grabbing in their hosts’ powerful jaws, or varnished to make them difficult or possibly unpleasant to grasp (think fingernails squeaking down blackboards!)

Shining Guest Ant – photo by Gus Jones

An on-line search for more information on the nature of the Shining Guest Ants’ relationship with the Wood Ants was inconclusive and left me with the impression that we do not really know if they solicit food from their hosts, raid their larders, scavenge their leftovers, eat their offspring or a combination of all of these.  About the only thing that that seemed certain was that the ones we were seeing on the surface of the wood ant nests were not foraging workers but males on the lookout for virgin queens.  Still so many mysteries under our noses that we have yet to unravel!

At least part of the attraction of these little creatures lies in their English name.  I find such triple-barreled names with unexpected descriptors very appealing, and the Shining Guest Ant now joins the pantheon along with such delights as the Trembling Sea Mat, the River Jelly Lichen and the Kinabalu Friendly Warbler.

So, we had a good day.  There is, however, a downside to being a naturalist.  As the eloquent and visionary American conservationist Aldo Leopold wrote in 1948 ‘One of the penalties of an ecological education is that one lives alone in a world of wounds’.  The loneliness is not so great these days of increased environmental awareness, but there are an awful lot of environmental issues to be aware of, and the attention spans of press and public are generally too short to achieve sustained solutions.  For many years Gus, an expert on Capercaillie (Tetrao urogallus), that rare giant woodland grouse, has been battling inappropriate developments in the mountains and forests of the Cairngorms.  As time has gone by he has cast his net wider in the quest for other organisms that will help him make the case that ancient Caledonian pine forests are not the right places to build holiday homes and retirement bungalows.  I fear he places too much faith in the power of Shining Guest Ants and other rare or little-known invertebrates, but it is good to know that he is out there, fighting the battles.  Tess’s mother is 102 and Gus’s mother was also a centenarian, so with that outstanding genetic heritage I look forward to them continuing to hold housing developers and the Cairngorms National Park Authority to account for many years to come!

References:

Martin, S. et al (2007)  Chemical deterrence enables a socially parasitic ant to invade multiple hosts.  Proc. R. Soc. B, 274: 2717-2721.

Meet Leif the Lucky

In my post Sheepwrecked, Sheepracked or Sheepwrought? I suggested that to help justify the maintenance of sheep grazing in the British uplands we needed to develop new breeds of sheep that cost less to manage.  Wool is worth very little these days, and one avenue that might be worth exploring, I suggested, was to cross the modern Easycare breed that does not need shearing (because it sheds its fleece by itself every year) with the Herdwick, the iconic Lake District sheep, and the Soay, probably the toughest sheep breeds we have in Britain.

The Herdwick is believed to be a descendant of sheep brought in by the Vikings from Scandinavia over a thousand years ago.  It is a distinctive sheep of great charm with a friendly white sock-puppet face, dark button eyes, shrekkish ears sticking out sideways from its head, sturdy and very hairy ‘bellbottom’ legs, and a fleece that changes colour as the animal ages.

Herdwick Ewe with Black Lambs

Herdwick Ewe with Silvered Lamb

The lambs are black, often with a bit of silver (rather like miniature Hebridean sheep) and usually with a white spot on the back of each ear, and they keep this dark colour into their second year.

Second-Year Herdwick

By this time their heads and legs have turned white and the contrast with the inky darkness of the fleece brings Uncle Fester from the Addams Family to mind.  As they age their coats get greyer, then the grey gets more silvery until finally the oldest ones are pretty much white.  Lovely in colour the fleece may be, but sadly coarse.  Wool suitable for hard-wearing carpets but not really for clothes.  Indeed I wonder if some of the frenzied aggression of the notorious Viking berserker warriors was due to wearing itchy Herdwick woollen clothing next to their skin as well as to the consumption of fly agaric toadstools.

The Soay, which I went to see this summer on its home turf of St Kilda, is a much older breed, tough but small, and probably pretty close in appearance and characteristics to the first sheep brought to Britain by Neolithic settlers six thousand years ago.  I will write more about them in another post.

Soay Rams, St Kilda

Soay Ewe, St Kilda

I ran the idea of an Easycare / Herdwick / Soay crossbreeding programme past John Vipond, a consultant (now retired) with the Scottish Agriculture College and widely respected as an authority on sheep farming.  John, I knew, had been actively promoting ways of reducing sheep management costs.  He was keen on the idea of crossing Herdwicks and Easycares, and had suggested it himself at various field meetings with graziers and farmers, but so far no-one had taken him up on it.  He felt that adding Soay to the mix would simply complicate matters.

Fools, they say, rush in where angels fear to tread, and as is so often the way serendipity lends a hand – or even, as in this case, gives you a hearty shove.  I have become a regular visitor to Ennerdale in the Lake District, scene of a very interesting rewilding project (about which I will post another day), and through this have made the acquaintance of Richard Maxwell, whose black Galloway cattle are being deployed to limit tree regeneration in parts of the plantation forestry that have been felled or thinned.  Richard also happens to have a large flock of Herdwicks.

Richard in Ennerdale

Back in Northumberland, my desire for a better understanding of the interplay between livestock grazing and vegetation has led me to become a volunteer with Flexigraze, a CIC (Community Interest Company) set up to provide conservation grazing services in North-East England (https://flexigraze.org.uk/).  Flexigraze makes use of an eclectic mix of sheep breeds that can thrive on the roughest of grazings including Manx Loaghtans, Hebrideans, Shetlands, Soays and Swaledales, plus ponies and Highland cattle for the really thick stuff.  Flexigraze is managed by Stephen Comber, who for his main commercial enterprise, I was delighted to discover, has a flock of Easycares.

Stephen and his Easycares

Both Richard and Stephen are thoughtful men, generous with their knowledge and deeply concerned about the future of livestock farming post-Brexit.  Richard gave me a stark insight into the economic penalty of having to shear his Herdwicks: he has about 500 sheep and this year he received 33p for each fleece i.e. £165 in total.  Shearing, however, cost £1.20 per sheep i.e. £600 in total.  Moreover the greatest expense was gathering the flocks in from the hills for the shearing: this took 2 men and their dogs 5 days at £100 per man-day i.e. £1000.  So the total cost was £1600 i.e. a net loss of £1435.

Richard and the Chosen Tip

Anyway, I sounded out both of them on their willingness to get involved with a cross-breeding experiment, and was very pleased when they came on board.  So last week found me with a borrowed horse-van picking up a fine, sturdy but somewhat grumpy one-eyed Herdwick ram from Richard’s farm.

Grumpy, I think, because Richard had already put his ‘tips’ (the Cumbrian dialect variant on tup or ram) in with his ewes and my guy seemed to be aware that he was missing out: he gave Richard a hearty farewell butt and stamped his foot at me when I tried to make friends.

Four hours later we were safely in Northumberland and he had mellowed enough to accept pieces of apple from me.

Meet Leif the Lucky

I am calling him Leif the Lucky (Lucky Leif for short) – this was the nickname of Leif Ericsson the first Norseman to reach North America, and seemed an appropriate name for a Viking sheep boldly going where none of his ilk have gone before and, I hope, founding a new breed.  Also his missing eye gives him a slightly piratical look.

Herdwick rams have a reputation for exceptional agility and randiness, so Stephen, who had not yet put his tups with his ewes, was anxious to get Leif and the four chosen Easycare brides away from his main holding in case he tried some extra-curricular matings.  This suited Leif who was enthusiastically investigating his unexpected harem even while in a sheep trailer with headroom only.

Lucky Leif and his ladies are now ensconced in a rank grassy paddock between the sand dunes and the reedbeds of the East Chevington Nature Reserve on the Northumberland coast.  They seem to have settled in and I think they are happy.

In the Reeds

Leif and his ladies

Lucky Leif

So now we sit back and wait.  The best scientific evidence is that the fleece-shedding switch gene is dominant so the lambs should inherit this from their mothers.  However other genes and other factors are in play when it comes to the pattern, timing and completeness of the shedding.  The health and diet of the sheep may play a role as well as its genetic heritage.  For it to be a success, the experiment has to produce sheep that can live out on the mountains all year round as well as being self-shedding, and we are unlikely to be able to gauge the results properly until late 2019 or 2020.  In the meantime though, I am looking forward to seeing if Leif’s lambs will have those white spots on the backs of their ears…..