Saturday, 17 November 2007

I can't see the trees for the wood

Spurred on by Richard Mabey’s new book ‘Beechcombings: The narratives of trees’, I have re-evaluated my relationship with woodland. I was raised on the Surrey-Sussex border, amid the verdant growth of deciduous woodland that extends over a large part of the Wealden landscape. Trees provided me with tools for play; they supported the insects and birds with which I became fascinated, yet all the time they remained a backdrop to my progression towards maturity. They were such an integral part of my childhood that I took them for granted and ignored them, relegating them to the role of scenery, in front of which I played out my youth.

Richard’s book has made me realise the extent to which I have underplayed the beauty and value of trees. I am not as confident in their identification as I am with birds, insects and other wildlife and, by not knowing them, perhaps I appreciate them far less than I should. When I first left Surrey I was struck by how open a landscape could be, perhaps no more so than in the fenlands of Norfolk. Separation from the woodland within which I had been so comfortable, and the feeling of loss that came with it, underlined the importance of woodland to me. However, it was the woodland (this community of mixed species and forms) that I missed, and I still did not have a relationship with individual species of tree. This has changed, a response to reading of Richard’s own experiences with woodland, of his strong bond with the beech and the role that particular trees have played in the lives of other people across the country. Even though individual trees, because of their size and longevity, genuinely do provide a backdrop to our lives, it is possible (perhaps even essential) that we also regard them as living organisms.

In this age of regimented and man-made materials, we are becoming increasingly divorced from natural products, like wood, and the inherent variation in quality and end use towards which such products may be put. The varying qualities of different woods, how they can be worked, how they burn and what they are best suited for, help define the qualities of the trees themselves – for example, the sturdy oak, the flexible willow. To properly understand them, you need to appreciate these qualities and take time to study the form of individual trees within the landscape. Many will have decades of history associated with them and knowing this (plus knowing that this history will continue to accumulate long after you are gone) soon brings the tree out from the background and into the central focus. It becomes a living individual, just like you.

Friday, 16 November 2007

A walk with a purpose

My early morning walks through the forest have taken on a new purpose. In addition to exercising my dogs (and indeed myself) I am now helping to chart the distribution and status of our birds. Along with many thousands of other birdwatchers I am participating in Bird Atlas 2007-11, a mammoth undertaking to map breeding and wintering bird populations within Britain and Ireland. The last time that this was done was nearly 20 years ago and much has changed since then. Buzzards have expanded their range to the east and are now breeding in Norfolk, making them a far more familiar sight in our skies than they were just a decade ago. Other species are known to be in decline and it is likely that we will see a contraction in the range that they occupy within the county, or a thinning in their numbers.

The project is being coordinated by the British Trust for Ornithology (BTO) and has two different components. First, a series of survey squares have been selected across the country and these will receive intensive survey visits from volunteer birdwatchers, twice in the winter and twice in the summer. I have taken on two of these squares, one where I walk my dogs and the other out near East Harling. Information from timed visits to these survey squares will be collated and then used to determine the abundance of different species across the country. We might find, for example, that Norfolk’s corn buntings are now concentrated in the fens or that our green woodpeckers are most abundant on the sandy soils of the brecks.

The second component has been termed ‘roving records’ and involves collecting simple records of birds from anywhere in the country. The song thrush or bullfinch that you see in your garden could prove to be an important record and can be submitted on a simple roving record form (available from Bird Atlas 2007-11, BTO, The Nunnery, Thetford, IP24 2PU). A record in winter of a fieldfare or a redwing will help the BTO to map winter distribution, while a summer record of a nesting long-tailed tit will reveal the breeding range. These roving records should be particularly useful for supplementing information from the more intensive, but time-restricted, counts made in the selected survey squares. Taken together they will supply the information needed by those addressing the conservation needs of our birds, providing an audit of bird populations and highlighting those species in need of additional conservation resources. So if, like me, you get out into the countryside (or a town or just watch the birds in your garden), why not get involved and make your contribution to Bird Atlas 2007-11.

Thursday, 15 November 2007

Mucking about with mammals

The other weekend I was fortunate enough to spend a very enjoyable morning with a group of mature students, teaching them how to find and identify mammals in the field. Much of the skill required to find and identify mammals actually centres on being able to locate and recognise mammal droppings and footprints – rather than the mammals themselves. This is because many of our mammals are elusive, avoiding contact with humans, and so are encountered only relatively infrequently. The signs they leave behind, however, can be found more readily and provide an ideal mechanism for establishing that a particular mammal has used the area. The students were all taking part in an evening course being run by the University of East Anglia. Each student was keen to develop his or her skills and to broaden their knowledge of our mammal fauna. Here, in Norfolk, we do fairly well for mammals and with a bit of effort you can encounter most of our terrestrial species – from the Chinese water deer that frequent the broads, through to the brown hares that do so well on our open arable farms.

When looking for signs of mammals you often spend a lot of your time bending over, crouching down or crawling about on your hands and knees. The grounds of Bayfield Hall, where Natural Surroundings is based, were our study area and, with the River Glaven flowing through the valley, we were soon able to find evidence of a range of mammals. Under the hazels were many of last years’ nuts, split open by squirrels. Adult grey squirrels split the nuts cleanly in two, but younger, inexperienced, individuals often make a bit of a mess and the opened shell is jagged and haphazard. Wood mice and bank voles, also partial to hazel nuts, open a smaller rounded hole in the shell, each with its own identifiable pattern of tooth marks.

Down by the river, on the areas of soft mud that we had smoothed over the previous evening, were the tracks of pheasants, brown rats and, in one spot, a passing stoat. These provided us with an opportunity to take casts of the tracks by using plaster of paris, something that I had not done since I was a child. This kind of hands-on detective work is great fun and it was clear that the students had enjoyed themselves. Of course, it has a more serious side as well, in that records of mammals (or evidence that they have used an area) have real conservation value. This is another important aspect of the course, teaching the students to collect and submit their records to the county biological records centre so they may be used more widely. 

Wednesday, 14 November 2007

Birds count cost of awful summer

It has been a poor summer for many of our breeding birds. The appalling weather that dominated from May through into July caused problems for nesting bitterns and lapwings, both caught out by rising water levels, and made life very difficult for nesting tits. It had all started so well, with the fine weather in April favouring early nesting species, like the long-tailed tits which had a bumper season. However, those birds nesting later in the year were caught out.

Species like blue tit and great tit time their nesting attempts to coincide with the annual peak in the abundance of caterpillars. They need to do this because each chick (and there may be up to 12 in a nest) requires something like 100 caterpillars per day. The arrival of heavy rain literally washed many caterpillars off the leaves, making food more difficult to locate for busy parents. Short on food, the growing chicks were also hampered by the fact that their parents were returning to the box wet. With far fewer body feathers than their parents, chicks quickly became damp and chilled and many a brood was reported dead in the nest.

Information from those with nest boxes in their garden made it apparent fairly early on that it was not going to be a good breeding season. These anecdotal reports have now been supported by the recently published results of systematic monitoring work carried out by the British Trust for Ornithology (BTO). Through the Constant Effort Scheme (CES), bird ringers working for the BTO collect vital information on movements, survival rates and productivity. Every summer, teams of CES ringers catch birds by using a system of special nets, with each net used in the same place and for the same length of time from one year to the next. This enables the researchers to look at the numbers of adult and juvenile birds that have been caught and, from this, establish a measure of breeding success. The 2007 breeding season has proved to be the worst on record for a number of species: blue tit productivity was down by half, that for great tit was down by a third and two migrant species (reed warbler and whitethroat) were down by a quarter. While a good breeding season next year may enable some birds to bounce back quite quickly, for others the poor summer is yet another thing that has gone against them. Some of the migrant species, like whitethroat, are facing problems on their wintering grounds in Africa and a poor breeding season here only serves to exacerbate their plight. We need to keep our fingers’ crossed for a better breeding season in 2008. 

Tuesday, 13 November 2007

November floods lure seabirds

Although the recent North Sea surge spared coastal communities, it did break through the sea defences near Salthouse, bringing flooding to the marshes west of Kelling. It was quite a sight to see this new expanse of water stretching away from the east bank at Cley. Sodden paths, now free from surface water, were covered with hundreds of worms, presumably killed by the saline conditions. A large pike lay dying on the edge of the one the drains and a tide-line of vegetation revealed the level achieved by the now subsiding waters.

This new waterscape appeared calm; sheltered from the northerly winds by the shingle bank, many waders and wildfowl took advantage of the new feeding opportunities. Small groups of brent geese, teal and wigeon, mixed with curlew, redshank and a solitary ruff. Many were feeding within feet of the coast road, providing good viewing for those brave enough to venture out under such threatening skies. One of the birds feeding in a newly formed roadside pool caught our eye as we followed the road east; a small pale grey and white wader, feeding in the water with a buoyant, almost clockwork, manner. This was a grey phalarope, a dainty bird which has been wonderfully misnamed. The species should be celebrated for the vibrant terracotta finery displayed during its short northerly breeding season and not the drab grey of its winter plumage.

The phalarope was picking tiny insects from the surface of the floodwater, moving forward and then rotating from side to side with the smooth transition of a mechanical toy on the top of a childhood music box. Each movement was so delicate that I found it hard to comprehend that this diminutive bird would spend the winter far out at sea, feeding in the waters off West Africa. That it was here, on the North Norfolk coast, was a result of the storms that had also pushed other seabirds close inshore. The phalarope would have been on its autumn migration, a very protracted affair given that the females may leave their breeding grounds in Iceland, Greenland and North America as early as mid-July. The males follow a few weeks later, once their dutiful role as single parent is complete. This was an adult, the plain grey back and wings showing no sign of the darker feathers that would signal a young bird. By now a crowd of birdwatchers had gathered to take in this aquatic ballet, the feeding phalarope occasionally rising into the air when spooked by other birds but always dropping back down into the same section of pool. The storms had provided it with a good feeding opportunity and given us a real treat.

Monday, 12 November 2007

Yuck, what is that stuff?

Most of the colours encountered in nature (at least here in Britain) are sombre and subdued. Rightly so, you may say, particularly when you think of a damp piece of woodland towards the end of a rather warm autumn. Those spots of bright colour, the hideous primary yellows and garish reds, are almost invariably pieces of litter, left by some mindless ruffian happy to despoil our beloved countryside. However, there have been times when my eye has been drawn to some almost luminous patch of colour which is natural in origin. These are the fruiting bodies of yellow slime moulds, crawling imperceptibly across the woodland floor.

Slime moulds can be pretty revolting to look at and, at times, seem almost alien in origin. Little studied, they have sometimes been classified alongside fungi, yet other authors have lumped them with the protozoa (simple single-celled organisms). However you view them, it is fair to say that these overlooked creatures are to be found just about everywhere on the planet (with some forms seemingly able to live submerged for several at a time). The part of their life cycle that we are most likely to encounter is the plasmodium; the slimy, almost jelly-like, stage which is mobile and gives rise to fruiting bodies; it is these fruiting bodies that are suggestive of a fungus. Most slime moulds produce a plasmodium that is just one or two centimetres across and able to travel up to 10 centimetres a day. Some of the largest ones can reach two metres in diameter and may weigh over a kilogram. Alan Feest, quite a fan of slime moulds, once related how he had stumbled across a large slime mould, draped over a tree stump and giving the appearance of somebody having tipped a can of whitewash over the stump. When he returned the next day, the slime mould had moved off part of the stump and onto a neighbouring bramble, leaving a trail of slime behind!

Fruiting slime moulds produce spores which, catching the wind, disperse over large distances. The spores are remarkably robust and may survive for many decades before ‘germinating’ or ‘hatching’ (I am not sure which is the more appropriate term) into a simple single-celled stage. This feeds on bacteria and grows, developing thread-like appendages in wet conditions (these help it to move around) but retreating into a cyst when it becomes too dry. At some point the unicellular stage develops into a plasmodium, creeps about and then fruits. This complex life-cycle, and the fact that these are organisms that blur the line between animals and fungi, make slime moulds rather special and, most probably, worthy of our attention, despite their odd appearance.