Tuesday, February 23, 2010

Alas, Poor Fulmarus glacialis...

Half a lifetime of beachcombing has left me with a box full of artefacts picked up from the strandline, including a collection of seabird skulls. I know that's a little weird (as my wife often points out) but these are fascinating pieces of evolutionary architecture. What strikes you immediately, when you first pick them up, is the combination of lightness and strength. The structure is pared down to the absolute minimum that's consistent with their function. Then there are those massive eye sockets, testament to the important of acute vision in these marine scavengers and predators. And the beak. The example above, identfied by Nyctalus, is a fulmar Fulmarus glacialis. The functional part of the beak - the buff-coloured section with that wicked hooked tip that probably hacked at innumerable food items during the bird's lifetime - is made of keratin, the same protein that forms our fingernails. In the dead bird it simply slides off the jaws and the lower beak has been lost in this specimen, while partial decay of the keratin in the upper beak has accentuated the hook at the tip, which is made of thicker, tougher keratin.

There are times when a bird's bill looks decidedly dangerous and you can't help wondering whether that glint in this gull's eye suggests that it's considering the possibility of tackling larger prey....

The second skull, above, belongs to a guillemot and in this one the keratin beak is still present on both upper and lower mandibles. Notice how, in the view from above, the upper beak is slightly curved to the right. Minor deformities are apparently quite common in birds' beaks. In this species the slim, streamlined head, adapted for diving, is a distinctive feature.

Sunday, February 21, 2010

When the Boat comes in.......

I like places that celebrate their heritage. This cavorting fish....

..... pursued by a long line of similar-shaped ridge tiles chasing its tail ......

.... and the fish motif on the street lamps..

.... and on the end of the public benches on the quay, where you can sit and eat your fish and chips, mean that you could only be ......

... in North Shields

Tuesday, February 16, 2010

Undulating Mosses

Steve Gale, over at North Downs and Beyond, has recently commented on the excellent new Mosses and Liverworts of Britain and Ireland: a Field Guide, published by the British Bryological Society. My copy arrived today and it is excellent, if  a little intimidating - the number of species seems to have increased since the last time I looked closely at these intriguing little plants. Above is Atrichum undulatum, known as Catherine's moss, which has distinctly undulating leaves (double-click for a better image) and capsules that are like miniature pepperpots when you pull the lid off - illustrated here. I once read that it was named after Catherine the Great of Russia (and was originally named Catharinea undulata) but I've never found out whether this is true or what she might have had in common with a lowly woodland moss. I think the lower photo shows Plagiomnium undulatum, also with undulating leaves, decorated with a light rime of frost. Now I've bought the book, I'll have to get my money's-worth and try to identify the other 761 British moss species...

Monday, February 8, 2010

Rock Drill

The shell that you can see embedded in this lump of limestone, picked up on the beach at Seaburn last week, once contained the living mollusc known as a wrinked rock borer Hiatella arctica. This remarkable animal settled on the rock and then used the coarse ridges on the outside of its shell to bore its way into the soft limestone. There are five holes bored by separate animals in this rock and they've converted it into the geological equivalent of a lump of Swiss cheese. As rock borers grow their hole enlarges and once they are completely within the rock their future is quite literally set in stone - there's no way they can get out. When they die their shells are often trapped inside, so when I shook this rock it rattled. Piddocks have a very similar life style.........

This is the live animal, in a rock that's been cracked open, revealing the two red siphons that it uses to circulate water through its body. You can see that this individual is a good deal larger than the entrance hole on the left, through which it draws its supply of oxygenated water and food particles that it filters out from the water current.

Friday, February 5, 2010

Call of the Wild

There are some wildlife sounds that instantly evoke the atmosphere of whole landscapes. For me it’s the sound of redshanks, which you can find at this web site. For me their calls summon up a host of memories of visits to desolate saltmarshes, windswept sandy beaches and surf on rocky shores. Anybody else got any iconic wildlife sounds that convey the same sense of place?

These redshanks were on the beach at Seaburn last weekend.

Thursday, February 4, 2010

Cold Enough to Freeze the Toes off a Turnstone

This turnstone that had lost all its toes on both feet was running around on the beach at Seaburn last weekend. It had no toes on either foot, which leads me to wonder whether it had hatched like that and that the defect might be a genetically-controlled developmental abnormality, rather than the result of an accident. It didn't seem to inhibit the bird's movement at all, although moving around on slippery rocks to flip stones over might have been a challenge. Check out the distinctive footprints.........

Tuesday, February 2, 2010

Glastonbury Thorn aka Roddymoor Pit-Heap Thorn

The Glastonbury Thorn of ancient myth is said to have sprung from the walking stick of Joseph of Arimathea while he slept near the ancient island of Avalon, now familiar to thousands of festival goers as Glastonbury Tor. When he awoke his stick is said to have taken root and sprouted leaves and flowers, so he took root too and introduced Christianity in Britain, so the story goes. In Mediaeval times a hawthorn that grew on the site and flowered in late winter and again in May was believed to be the very same plant. This twice-flowering hawthorn apparently had two trunks, one of which was destroyed in the reign of Elizabeth the First and a second which was finally destroyed in the Civil War by Roundheads. Winter-flowering hawthorns have been planted there since, reputedly from cuttings of the original plant and I believe that one still grows there.........but we have another example growing on an old colliery spoil tip at Roddymoor, up here in County Durham.

These twice-flowering, winter - and spring-blooming hawthorns have been reported from time to time in other parts of Britain and they are all likely to be genetic mutants whose normal response to lengthening days – a signal for bud-burst and flowering, has become confused. This particular specimen was planted about 40 years ago on the old Roddymoor pit heap, in an experiment to see which plants would establish in rock, poor soil and coal dust that was parched in summer and waterlogged in winter. Happily it’s still there, growing slowly but surviving. I picked a twig about three weeks ago which is now in full flower in a vase on my desk today - and is portrayed above.

The plant has several peculiarities, possessing few thorns and bright red buds - see photo above, taken about three weeks ago while there was still deep snow on the ground and showing bud scales beginning to loosen even then. It’s also Midland hawthorn Crataegus laevigata (identifiable by its pair of stigmas), and not the common hawthorn C.monogyna which predominates hereabouts.

Hawthorn is a genetically variable species, notably in its response to spring. You only need to look along a stretch of hedgerow in late February to see some plants almost in full leaf and others still with tight buds that show no propensity to produce leaves until late March. Our local ‘Roddymoor Thorn’ is, I guess, just an individual from the extreme end of this spectrum of response to lengthening days. Still, it’s in pole position to respond to climate change, early springs and milder winters – although this winter hasn’t done it any favours.

There are some other peculiar hawthorns hereabouts, including a yellow berried one which I must remember to photograph next autumn.