Thursday, 23 February 2012

As I was saying...

My, how time flies when you are not having fun.  Now...where was I? 

Oh yes - rhynchokinesis - otherwise known as handy-bendy-beak syndrome.  I have touched on this interesting curiosity before but what brought it back to mind was a couple of black tailed godwits feeding in the flooded fields on Holy Island the other day.  The effect was not at all visible when watching the birds but a millisecond caught in a megapixel just happened to give a hint of it.

I came across a much better picture than mine here. (Steve Gale at North Downs and Beyond talks about blog envy - I know the feeling).

Many people assume that all birds beaks are solid, hard structures. Far from it - particularly in the longer billed waders like the godwits, curlew and snipe. Next time you find a dead one of these, I recommend that you explore this.  If it's a bit stinky by the time you come across it, this will be when you realise that all that time spent carrying a pair of surgical gloves in your pocket was not wasted. The bill tip is not only softish and flexible but well supplied with sensory bits and pieces. (For more on this - see my earlier post here)

The New Naturalist book 'Waders' explains that the upper mandible can be raised or lowered independently of the rest of the bill.  Thus you can have the tips only apart or the tips together with an open gap in the centre.  Certainly, having a 'hinge' towards the tip of a long bill must give much better dexterity when picking up small prey items. 

If you don't already carry a pair of surgical gloves at all times, rush out and get some.

Monday, 19 September 2011

Seeing Red

Wobbling my way along a quiet lane near Wooler in North Northumberland yesterday, I was gently bonked on the head.

Working on the principle that unripe nuts don't just drop off trees on still days I stopped the bike and looked up.  Nothing. Silence.  But I knew it was there somewhere so I parked up the bike and stood and stared.  Five minutes passed. Nothing.  However, when it comes to capacity to stand and stare I'm right up there with the best.  The little blighter cracked first and showed itself but not until after fully 10 minutes of stand off.

It moved across a branch and looked down at me making a quiet alarm call. At each call its whole body jerked as if to force the air out of its lungs.  I've seen this before but done with more vigour, accompanied by a little jump followed by all four feet banging on the branch simultaneously, making an audible knocking sound but this one made do with a shudder and a squeak.

We are very fortunate in Northumberland to still have the red squirrel though the inexorable northward march of the grey keeps it under threat.  Where I work in Co Durham to the south, the reds have long gone.  Greys are commonplace so I know that if this had been a grey I would not have had to wait 10 minutes before it made itself known.

Many people hate grey squirrels but actually they are fascinating to watch and wonderfully inventive. I take my squirrel fur hat off to them.  I have a bird feeder outside my first floor window at work and greys regularly appear on the external window sill looking in at me.  They just shin up the brick wall and chew the feeders to bits.  If I disturb them they just jump off, land on the grass and lollop off waving metaphorical double digits.  As a survival machine they've got what it takes. But I'm sorry, American readers, reds have cute factor 10, and being our native squirrel, yours has no chance in the popularity stakes round here.

Sometimes I have thought that the fate of the red squirrel is sealed, that we might as well stop trying to kid ourselves otherwise and give up trying to protect them against the tide of greys. However, you only have to see one like this to realise that the effort is well worth while.  Even if it is only postponing the inevitable, let's stick with it as every encounter with this marvellous animal is a priceless bonus.

Thursday, 15 September 2011

Come in No 62, your time is up..

A few posts ago I promised to bore you with my bird ring big fish story once I found the photos.  So here we go.

My most impressive ever bird ring find was in the mid 1980s.  Wandering along a Hebridean beach, I saw the tip of a brown feather sticking out of a bank of seaweed.  It looked at first like a juvenile gull but, as ever, I went to dig it out and check what it was.  A major expletive ensued when I pulled on it and out from the seaweed appeared an immense hooky beak and a huge taloned foot.

There had been just the two of us on the whole beach so I nearly jumped out of my skin when a deep voice from nowhere growled, 'What have you got there?  I looked up to see a huge dodgy-looking bloke with a spade held against his shoulder like a rifle.  Now this was at a time when there was a battle going on between farmers and conservationists about eagles and their impact on sheep farming.  There were strong suspicions that eagles were being systematically poisoned or shot on certain estates. So, my brain worked it out faster than the blink of an eagle's eye.  Having shot the bird, buried it in the seaweed and been rumbled, he was now planning to bludgeon me to death with the spade and bury me in the seaweed too.

The remnants of no.62
I survived, but I had a feeling that the evidence wouldn't if I left it there. But what exactly does one do with a rank eagle in the middle of nowhere. The best I could manage was to retrieve the skull and, as I couldn't get the ring off the leg, I got the leg off the bird.  Lunch was turfed out of its carrier bag and in went the stinking bits of eagle.

At this point I wasn't sure what it was. Golden eagles were well established on the island but the re-introduction of the white tailed sea eagle on Rhum had been going well and birds were beginning to spread. One thing I did know for sure was that the skull was absolutely enormous.

Once home I was able to confirm from the skull measurements that I had indeed found a white tailed sea eagle.  I reported the find to the BTO ringing scheme and got in touch with RSPB Scotland and the sea eagle re-introduction programme people.  They were keen to send the skull off for any brain remnants to be tested for poisons or pesticides.  Someone from the RSPB went out, found the rest of the carcase from my description of the location and had that tested too.  The results were inconclusive for evidence of deliberate poisoning and it was impossible to tell if the bird had been shot. One worrying outcome though was that high levels of the pesticide residue DDE (a breakdown product of DDT) and also PCBs were found in the brain tissue, presumably acquired through the marine food chain and probably contributing to loss of condition and the death of the bird.

This was all the more concerning when the ringing details came through.  The bird I found was less than a year old, one of two young ringed at a wild nest the year before.  The demise of this bird was a sad blow to the re-introduction programme at that point as breeding was only beginning to get established beyond the Rhum release area.

25 years on, it's good to know that the re-introduction programme has worked in spite of the early loss of No. 62.  Without it I would not have been able to enjoy the magnificent sight a couple of years ago of a sea eagle bothering a golden eagle that had just been bothering a raven.

(Apologies for the poor picture quality. These are scans of prints that weren't sharp in the first place!)

Sunday, 11 September 2011

Sorting out one's Eristalis bulge

There is something special, I find, about watching a hoverfly in suspended animation right in front of your nose, especially if you can get the sun on it but highlighted against a darker background. They stay so perfectly positioned with just a glinting blur of wings.

Last weekend I spent a happy half hour fiddling about trying to catch this in a photograph.  I've had a draft post hanging round for a while, incomplete, and just as I was about to finish it off, in pops a post from Blackbird's splendid Bugblog with a photo exactly the same as the ones I was trying to get only different.  The difference being that hers is nice and sharp and top quality ....and mine isn't.  Maybe if I keep it small you might not notice.

It's a little easier to focus once they settle.....

and this one was easier still. It's a wrap.

(If anyone would care to put a name to these for me that would be jolly decent.)

The bee mimicking hoverfly below looks odd in that it seems to have only one eye - you can't see the clear line of division normally visible between the two.  That's because I caught it in the middle of cleaning its eyes and it has rotated its head through a full 90 degrees.  They are fascinating to watch as they clean their lenses using the front pair of legs like windscreen wipers to scrape over the eye surfaces and scoop off the dust etc.

In terms of identifying this one, I made use of Stuart's helpful 'Eristalis bulge' tip - see his Donegal Wildlife blog - where he does a nice piece on hoverfly i/d for numpties (thanks Stuart).  This hoverfly had the tell tale loop in the wing vein which identifies it readily as one of the Eristalis group.

And talking of hovering, I think it's time for my mouse to hover over the amazon web site and find that book on Syrphidae identification.

( PS: For more super-duper superior flight shots - check out Phil's post here.)

Thursday, 1 September 2011

Second to Noon

Some while ago I bemoaned the lack of information to be had about one of my favourites flies – Mesembrina meridiana aka the Noon Fly.  This bonny matt black insect with unreal gold angular decorations on its head and a tasteful hint of gold on the wings bothered me because I could establish so little about its lifestyle other than it laid eggs in cow pats.  (See my earlier post here)

Phil Gates pointed me towards a book – though I thought he was having me on when he said it was called ‘Insects of the British Cow Dung Community’.  I mean, I know plenty of people who talk a load of cow manure but who in their right mind would write a book on it let alone give it such an evocative title.  Well, one fine chap and largely unsung hero called Dr Peter Skidmore of course – published by the Field Studies Council.  A hunt for the book proved fruitless as it was long out of print.  I forgot about it until Mel Lloyd posted on cow pats a while ago on her Sandy Wildlife blog.

To cut a long story short I now have my hands on a copy after handing over a deposit (sorry) to the library loans people.  What a gem it is and I suspect, between this blog and Mel's you haven't heard the last of it by a long chalk.
So.....I now know that the little female noon fly lays no more than 5 eggs in her whole short life.  These are laid one at a time, two days apart in soft fresh dung.  Trouble is that within two days any one cow dollop will have crusted over, so she is a one-egg-per-pat kind of girl.  It follows that if you were to find a lot of eggs in one pat they must each have been laid by a different fly.  Elementary my dear Watson.  (He never said that).

Within an hour in the nice warm steamy slop, the egg has hatched .  By the third instar stage, the larva turns carnivorous and munches its way through large numbers of maggots of the face fly (Musca autumnalis).  This fly is responsible for spreading various unpleasant diseases in cattle so you see, this delightful dipteran is actually the farmer’s friend.
Another Skidmore gem is that the noon fly maggot is the largest you will find in your average British cow pat and, he says,  is popular for that reason with both anglers and rooks. (Though somehow I can’t imagine many anglers fingering their way through fresh dung to look for noon fly maggots).  He omitted to mention choughs,  which make a very decent living by sticking their noses into cowpats rooting out goodies, no doubt including noon fly maggots, as I observed first hand on Colonsay. earlier this year.

(Distant) chough poking in a cow pat

Chough looking for a cow pat
So, a toast to Peter Skidmore, sadly no longer with us, for his splendid legacy and a plea to someone to reprint his book asap.

For posts from other noon fly fans try:-
The Living Isle
Martin's moths

Monday, 8 August 2011

On the Technical Use of Gastropods (or how to stop a squeaky wheel)

I stood on a slug on Friday. Arion to carrion. You see, they closed the car park near my office so I now have to park right up the top of the hill.  This means that I start my day with a ten minute scenic detour along the track at the woodland edge. (Every cloud has a silver lining).  So it was this morning that I disturbed a roe deer and as it stepped out onto the track right in front of me, I stomped to an emergency stop and experienced that unmistakable oozy sensation of shoe upon very large slug. (Every silver lining has a cloud.).

I'll save you the gore of the squashed one - the Arion ater that I stood on looked like this before the close encounter with Doc Martin.
Arion ater, Mountjoy, Durham
Now here's a thing. In rural Sweden, in days of yore, their 4-wheeled carts had hard wood tree trunk axles, and used to squeak like hell and drive everyone crackers.  In no time some bright Swede realised that a couple of those big Arion slugs were just the job - simply squash them in the gap and hey-presto, silence.  You can almost hear the sighs of relief and the lowering of shoulders as the hapless molluscs do for the cart wheels what WD40 just did for my door hinge. 

Furthermore, immigrant German glass blowers in Sweden's southern parts collected Arions to smear on their frying pans when cooking pancakes, and in Essex, kids collected them along the railway lines to sell to the rail workers to lube their wheels (just the job when badger lard is in short supply).

If you think I'm making this up, read the whole paper, gloriously entitled, 'Black Slugs (Arion ater) as Grease: A Case Study of Technical Use of Gastropods in Pre-Industrial Sweden'here. Nice one Ingvar.

The colour variation in Arion is interesting.  There is a north-south divide. In Northumberland, I've only ever seen the jet black version. They are black in Sweden too.

Arion ater, Chillingham, Northumberland
In the south of England I read that most are red/orange/white ie anything but jet black. (Can my southern English readers confirm this?).  In Durham, there seems to be a bag of all-sorts as if we are on the overlap.

Brown ones of varying shades of light and dark.
Black ones with a snazzy orange and black skirt.
I had some interesting discussion with Phil Gates about this on his blog a while back.  Worth a look (here) if you missed it, if only for Phil's magnificent close up pictures which, as per, knock the spots off mine.

(Postscript - 27-08-11:  Have a look at Blackbird's excellent blog for an interesting post on species and colour variations. The link is here.   Looks like I will have to edit my post to read Arion sp. !)

Wednesday, 20 July 2011

This Shag Incapacitated

900,000 birds are ringed every year in the UK.  That's pretty impressive considering this is nearly all done by amateurs.  Now, I'm always on the lookout for dead stuff and assiduously check every leg I find, yet it is a rare enough event to trigger a surge of excitement whenever I find one that's ringed.  So this dead shag was a welcome find on the Bamburgh shoreline in Northumberland. (Sorry if you are reading this while eating your tea.)

As well as the usual numbered metal ring this bird also had the large blue ring above, intended to be readable from a distance while the bird is still alive.

A few weeks after reporting the find (online here) I received an email to tell me that my shag had been ringed at the Isle of May Bird Observatory in the Firth of Forth last June as a nestling. Sadly, this one didn't see its first birthday, well short of the record age of a recovered shag of 29 years 10 months 25 days.  The British Trust for Ornithology records seem to show regular movement in both directions between the Isle of May and the Northumberland coast. (see map)

According to the BTO, the ring recovery rate is less than 2% so its hardly surprising that you find so few of them.  I suppose this means that ringing is a pretty inefficient way to study how birds move about, how long they live etc. Up to now its been the only practical way but I do wonder if the days of mass ringing might be numbered as technology gets smaller and cheaper. Just look at the recent cuckoo studies - more information discovered in a week or two than in decades of ringing.

So, this shag on a rock was a nice find but my most impressive ring - and I'm still dining out on this one- was 25 years ago on the Isle of Skye.  I'll bore you with the story as soon as I find my old 35mm slides. Don't hold you breath though - it could take some time.

Tuesday, 19 July 2011

Blown away (again)

Every year stuff comes round and stuff moves on.  Another year, another swallow.  Marvellous though all of the seasonal comings and goings are, I guess we all have those handful of special things that manage to gobsmack us each and every year even though we've seen it all before. 

I was standing in an overgrown field staring at butterflies but it wasn't the ringlet that did it. It was the momentary reflection of sunlight  in the corner of my eye followed by an unmistakable plasticky clatter of wings and then the breathtaking moment when a brand new dragonfly perched on a hazel leaf right in front of me. As I slowly rotated my head to get a proper look without scaring it off, so the female southern hawker slowly rotated its head to and fro and we scrutinised each other. There is no escaping the immense fixed eyes that fold right around the top and sides of the head.

The big hawkers are truly astonishing insects, right at the top end of my list of living things that impress me anew year after year.  I began compiling a top ten in my head of things that never fail to blow me away again with each annual first encounter.  The year's first harebell among the marram grass; the sight and sound of massed geese dropping out of the sky in a Lindisfarne dusk after a summer in the arctic; the first full throated blackbird song of the year; the smell of gorse blossom in early summer sun......  I wonder what yours are?

To see the empty nymph case of a Southern Hawker, click here . The mould of the eyes is fascinating.

Sunday, 5 June 2011

A Colonsay Abstract

It was something  of a surprise to me to discover the spectacular jagged cliff scenery on the west coast of Colonsay.  The many ledges support strong colonies of seabirds and in a few areas it is possible to get very close.

Guillemots are always interesting to watch en masse on their breeding cliffs.  Quite a few of the birds on these cliffs were ringed and it was possible to read some of them using John's telescope which cranks up to 60x.  Passing these records on, it turns out that all the birds had been ringed at this same spot and one dated from 1993. Not bad, but the oldest known ringed guillemot in the UK was  31 years 9 months 11 days old when it was found dead in 2004.

Guillemots are fine but there is just something about their close cousins the razorbills which I find more appealing.  I think it's the bold black and white plumage together with a more interestingly shaped bill with delicate white lines that gives it the edge in the elegance stakes.

The angle of the light together with the dark nature of the rocks seemed to emphasise their black and white patterns and I rather enjoyed the effects this created if you scrunched your eyes up.  Try it.

Having had a go and failed miserably to capture this effect in a sketch, I reverted to photographs, and ended up with the abstract collage at the top of the post using black and white shots with all the mid tones removed.

Tuesday, 31 May 2011

On the tracks of otters

These are otter prints.  The animal has been bounding along (diagonally left to right in the photo) using the typical bendy movement it shares with its cousins the weasel and the stoat. 

What you see are characteristic clusters of four separate footprints.  First, the left and right front paws hit the ground  slightly out of sync and one in front of the other. As the otter's momentum carries it forward, the body moves over these two prints until the two back paws plonk down beside marks left by the front feet. 
As followers of my previous tracking posts will have guessed by now, I applied my usual techniques of skill and field craft to work this out - which is to say, none whatsoever.  I watched the otter bound by and then went up and had a shufty at the tracks. 
Here is the first bit - front paws hitting the ground, one at the back, the other further forward.  The back legs start to move through.

Then , kerplonk, down go the back feet right beside the front feet  marks but managing not to overlap any of them.

The push off given by the back legs together with its forward momentum, propel the animal quite a way forward such that the next time the front feet hit the ground the animal is far enough away to register a separate and distinct group of four.

With an otter of this size moving at a reasonable pace but not full tilt there is about 9 to 10 inches between the groupings.

The sighting of this otter was just one of those fortuitous things that is bound to come along if you spend enough hours outside in the right places.  Apart from a few tracks and signs it had been an otterless week until the last hour of the last day on Colonsay when I decided to wander along the beach to see off the last ten minutes before heading off to the ferry. I looked up in response to a movement and stood riveted as this otter ran along the top of the beach, not 20 yards away.  Jammy or what!