Sunday, 17 October 2010

Simple skills of a silken kind

It is on these damp autumnal mornings that the architectural skills of our many and varied spider species can be best appreciated. While bits of wall display simple webs, the gaps between plants support the more-skilled constructions of orb-web spiders belonging to the genus Araneus. Undoubtedly the most familiar of these is the Garden Orb-Web Spider Araneus diadematus, delicately-marked with greys and browns and with a white cross on her back. It was this cross that saw her venerated widely during the Middle Ages and which provides a useful means of identification.

Dew-covered webs provide an opportunity for you to view the web’s construction, revealing the fine threads typically formed by the spider during the previous night. The Garden Orb-web produces a sizeable web, with a defined central hub of meshed thread. Outside of this there is a narrow spiral, known as the strengthening spiral, which circles six or seven times around the hub. Radiating out from the centre are two or three dozen threads which stretch out to the stout outer frame. It is to these radiating threads that the main spiral of threads is attached, the spiral beginning a little way out from the central hub. This leaves a gap, known as the free zone, between the strengthening spiral and the main body of the web itself. The main spiral is the key to securing a meal, since the spiralling threads are studded with blobs of glue. Flying insects unfortunate enough to encounter the web are held fast, affording the spider the opportunity to seize the prey and deliver a venomous bite. Some prey are deemed too large or too dangerous to be tackled, for example wasps, and the spider simply cuts them free rather than risk injury.

Sometimes the spider will sit motionless, head down in the centre of her web, her eight legs alert to the vibrations caused by an insect caught in the web. At other times she will tuck herself away on the edge of the web and use a signal thread, which runs from her hiding place to the centre of the web, to detect prey. That the spider can move across the web with impunity, not becoming caught in her own sticky trap, comes down to her use of the non-sticky radial threads when moving about the web. She also makes use of special oily secretions which cover her legs and reduce the chances of her becoming stuck.

These webs are particularly important to the female orb-web spiders, as they need to secure food in order to complete their series of moults and to produce the hundreds of eggs which will be deposited nearby at the appropriate time.

Friday, 15 October 2010


It is a damp afternoon, and the light is not that good, but at least the rain has ceased and I have an opportunity to slip out of the house for an hour or so. I’ve come to the paddocks, an area I know well and where I can lose myself in patient watching. Setting up the scope I stand with my back to the ash and conifers, from which rotund drops of water descend noisily through the foliage. The sound of these falling drops is, for the most part, regular and soon filters itself from my hearing. Every now and then, however, a whole series of drops are set loose by one of the many Grey Squirrels that these woods hold.

Slowly I begin to unravel the soundscape; the soft calls of Coal Tits and Goldcrests, a Robin already in winter song and the distant calls of Jackdaw off towards the house. Patience is the key here and I must stand quietly watching and listening. It feels much later in the afternoon than it actually is, the dark clouds adding hours to my perception of the time. It feels as if the creatures around me are settling down for the day, taking in a last feed before going off to roost. After a while the cloud thins and the light improves. As if prompted by this signal, a party of tits flutters through the Hawthorns before crossing the track directly above my head. These are not the only creatures using the scraggy bushes in the middle of the paddock. A lone Grey Squirrel is picking Hawthorn berries and, although part hidden from sight, I’d say he was removing the pulp to get at the stones within.

Other birds are passing overhead: a steady stream of Wood Pigeons, a couple of Jays, a small party of Siskins and two Cormorants, the latter possibly on their way to the pits at Cranwich. Goshawk is occasionally seen passing over here but it is Sparrowhawks that I see today.

There is much to be said for just standing and watching. It teaches you patience, as you slowly immerse yourself in what is happening around you. At times you can become possessive of the solitude that this form of wildlife watching delivers, frustrated should someone else stumble into your seclusion with a cheery hello and a questioning ‘much about?’ On a damp afternoon like today I am left to my solitude and able to spend a good two hours uninterrupted by nothing more than a distant tractor and a couple of low ‘whumps’ from the range. I’ve had a good breath of air, freed my mind of any troubles and now feel in need of home and supper.

Thursday, 14 October 2010

Roads take a grim toll

The predominantly rural nature of Norfolk, with its scattered villages and small market towns, places us within touching distance of much of our wildlife. However, the fragmented nature of our settlements does mean that we depend upon a network of roads to support us as we go about our daily lives. Roads and wildlife are not easy companions and the growing volume of traffic takes a heavy toll on the countryside.

The most direct evidence of this impact comes in the form of the countless mangled corpses that litter our roads. At this time of the year, with the crops recently harvested, I often see dead rats, together with Rabbits, Brown Hares and Pheasants. I also see larger mammals, like Muntjac and Chinese Water Deer, Red Fox and Badger. Just the other week I saw two adult Badgers dead by the road. Up to a third of the county’s young Barn Owls may be killed by motor traffic during their first year of life, a heavy toll on a species whose breeding population underwent a significant decline in the past. There are some stretches of road within the county that seemingly pose a particular threat to the owls which attempt to nest nearby.

The impact of roads, however, goes beyond the direct physical consequences of a collision. Roads can act as a barrier – especially the larger ones – limiting the movements of small mammals, amphibians and invertebrates, reluctant to cross this artificial microhabitat devoid of cover. Pollutants from our vehicles and the litter that irresponsible drivers and passengers fling from their cars can harm the environment and the wildlife it supports. The stub of a cigarette can cause a fire, destroying wildlife habitat and resulting in the loss of species. Then there are the more subtle effects. For example, research has revealed that songbirds may be unable to maintain breeding territories alongside busy roads because the traffic noise drowns out their territorial song, effectively robbing them of the means to attract a mate and defend an area in which to raise a family.

Some of the impact associated with roads can be reduced through careful planning and design. The construction of special underpasses or overpasses can provide corridors of natural vegetation through which wild creatures can safely cross the road. Screening vegetation can reduce the distance over which traffic noise can be heard and careful management of the verges can reduce their attractiveness to small mammals and hence to predators like owls.

We, as drivers, can also make a contribution by being more aware of what is around us as we drive and by keeping our speed down, affording us more time to spot and avoid wildlife on the road.

Wednesday, 13 October 2010

Transatlantic origins

The changing of the seasons marks a turning point for much of our wildlife, often prompting large-scale movements to other habitats or countries. October is the month that I, as a birdwatcher, feel reinforces the sense of connection with far away places, underpinning the complex movements taking place. Our position on the western fringe of Continental Europe means that we are well placed to see migration in action; as summer visitors depart so winter ones arrive and others pass through on passage.

Over recent days I have watched the weather forecasts, charting the movement of systems from both east and west and anticipating what they might deliver to our shores. For example, a storm system hitting the eastern seaboard of North America might pick up birds migrating south and carry them across the Atlantic. It seems such a great distance but such is the speed of these grand weather systems that they have the potential to deliver even the smallest and seemingly least robust birds to our shores. The birds that make landfall here, thousands of miles from where they should be, are known as ‘vagrants’. While certain vagrants reach us fairly regularly, with a dozen or so turning up annually, others are rare, perhaps with just a single individual recorded.

A fortnight ago I was on Blakeney Point watching one such visitor, a bird whose arrival the day before had attracted a crowd of birdwatchers even though the chances of securing an identification were slim. The bird in question was a small American flycatcher, one of a group of similar species that are notoriously difficult to separate in the field. Although originally thought to be a Yellow-bellied Flycatcher, it soon became clear that the bird was either an Alder Flycatcher or a Willow Flycatcher. These two species were, until very recently, thought to be a single species and it is only because of subtle differences in their songs and advances in genetic analyses that each has been elevated to species status. Only one of the two, Alder Flycatcher, has occurred in Britain before and its identification was only secured because it happened to be caught by a licensed bird ringer.

Alder Flycatcher breeds from Alaska to Newfoundland, occupying a more northerly breeding range than its relative, and it winters from Columbia to Peru. Examination of weather maps for the period leading up to its discovery, suggests that the bird had been caught in that east coast storm, sweeping it across the Atlantic, perhaps via Iceland. Its arrival in Norfolk may seem miraculous, especially with vagrants from the east present nearby at the same time, but it does underline the role that weather systems can play in bird movements. 

Tuesday, 12 October 2010

Getting wet is good for you!

A philosophy no doubt shared with many regular readers is that you should experience things in life and make the most of it. Part of this approach means getting out there and immersing yourself in the natural world, rather than living within the narrow confines of your home and work environment. So what if it is raining outside – it is only water after all! This was something that came up in conversation as three of us battled our way out to Blakeney Point the other morning, with a full North Sea gale battering our senses and threatening to hurl us from the shingle ridge. This was experiencing the full power of the natural world and, at the same time, sharing its inherent beauty.

Towering fronts of dark cloud dominated the sky, as crashing white crests of sea were hurled landward. The combination of wind and water worked to produce handful-sized balloons of foam that were carried inland by the wind. At one point the shingle was so thickly covered with this foam that it was as if we were trudging through snow. While the larger seabirds laboured against the wind, the smaller waders were flung with rapier speed in sweeping arcs that carried them along the narrow ridge.

Further ahead we could see bands of rain, bands that were moving so quickly that each shower was brief but intense. In between these squalls, there were brief moments when the sun pushed through, shafts of warmth and brilliant light piercing Payne’s Grey tones that would delight a painter of seascapes. The squalls also delivered migrant birds, with little falls of thrushes, chats and finches forced down to take shelter in the low vegetation. No doubt there would be some rare birds in with these but whether we’d see them or not was a very different question – while the cover on the point is limited it is amazing how birds will tuck themselves in as they seek to recover from their exertions.

After several hours out on the Point, and with memorable encounters with juvenile Redstarts and a recently arrived Short-eared Owl, we began the long journey back to the car at Cley. The pattern of squally showers continued but this time they were no longer ahead of us but right on top, unshifting. The heavy rain was, at times, quite literally horizontal and so fierce that visibility was reduced to perhaps a dozen metres. We were glad of our waterproofs which, for the most part, kept us dry. Even so, once back at the car we decided that we too needed to tuck ourselves away in order to recover from our exertions; the chip shop at Wells-next-the-Sea providing just the right place!

Monday, 11 October 2010


A barrel-chested outline reveals the presence of one of our more powerful seabirds – the Great Skua or ‘bonxie’ as it is known to many birdwatchers. Today, with the full force of the north wind coming in off the sea, we are fortunate enough to see a number of these magnificent birds (including a party of five together) as we crunch our way out to the point.

These are the largest and most powerful skuas; related to the more familiar gulls they are often described as the pirates of the sea, robbing other seabirds of food and stealing chicks and eggs.  Another source of food, in the form of fishery discards, has been particularly important for the bonxies, allowing their population to recover from decades of persecution (young bonxies were taken from the nest, fattened up and then eaten) and expand. With 60% of a global population of some 16,000 pairs, Scotland is an extremely important breeding area for these birds and they seem to be doing ok, although there is some concern over the very high levels of heavy metal and organochlorine pesticide residues found in their body tissues. As top predators, these skuas make good bioindicators of the wider condition of the marine environment.

The skuas move south in the autumn to winter in more favourable conditions south to the Bay of Biscay and into the western end of the Mediterranean. It is during this period of autumn passage that you may see them along the Norfolk coast, often singly but occasionally in larger groups. Like many of the other seabirds passing through on passage, the best chance of viewing them comes when the winds are strong and onshore. Most of those breeding in Scotland pass down the western side of the country but some do exit the North Sea via the English Channel and it is these birds that pass through the county’s waters.

Interestingly, some Great Skuas take short cuts by heading overland and it is not uncommon to see birds heading into the Wash and then gaining height to strike purposefully inland, following the Nene or the Ouse. This behaviour explains the presence of a Great Skua just last week at Graffham Water.

Great Skuas are fairly obvious and easy to identify, not least because they have a distinct profile. As well as the barrel-chest already mentioned, these thick-set birds have short but broad wings, with a distinctive white crescent often visible at the base of their main wing feathers. As for the name ‘bonxie’; well, it is thought to come from the old Norse word ‘bunki’, from which is derived the Shetland term ‘bunski’ often applied to a dumpy or heavily clothed woman.