Saturday, 11 December 2010

Sociable sparrows make a welcome return


It is good to see the House Sparrows return to the garden in force. Each morning they arrive from further down the street, a boisterous posse of grey-capped males and chattering females. This chattering becomes all the more evident once the birds have fed, the flock retiring to the thick of next door’s jasmine to indulge in communal banter. ‘Social singing’, as it is known, appears to be an important component of House Sparrow behaviour, its role tied in with social status and flock cohesion.

These are sociable birds and the winter flocks bring together individuals from several local colonies. Many of the youngsters present within these flocks will roost together in thick vegetation, while established pairs often retire to their nest site. Winter flocks of this kind not only provide benefits in the form of greater knowledge of food availability and lower individual risk of predation, but they also serve as the opportunity through which young birds can disperse away from the colony in which they were born.

Cohesion of sparrow society comes from the social hierarchy that is established through plumage and display, and ultimately backed up by force if necessary. In the eyes of a female, the badge which illustrates the suitability (and hence status) of a male is the size of his black bib. The most successful males are those with the biggest bibs and you will see subordinate birds quickly defer to these high-ranking males in many social situations (most notably in access to food, dust bathing opportunities and females).

Our House Sparrows were visitors when we first moved into this house but we lost them soon after, the landscaping of a neighbouring garden removing the cover they favoured and they ceased to venture this far up the street. Now that the vegetation next door has matured, we have seen their return. House Sparrows rarely venture far and for several years it has been frustrating to hear the colony further down the street, knowing they would only rarely reach our garden.

Cover is important for House Sparrows, providing feeding opportunities, protection from predators and a platform for the social singing. Other factors also play a major role in determining House Sparrow numbers, and key changes in the nature of urban landscapes have seen the House Sparrow population effectively halve since the early 1980s. The loss of nest sites, following the introduction of new designs of roofing tile and barge board, coupled with the clearance of scrubby habitats, increased use of pesticides within our gardens and increasing numbers of competitors and predators have all been linked to sparrow decline, even though we have yet to determine which of these is the most important.

Friday, 10 December 2010

Bullfinch


It is one of the coldest mornings of the year and I am glad to be on the move, working my way around the local lanes and tracks for Bird Atlas 2007-11. I have written of this national stock-take of Britain’s (and Ireland’s) birds before, a periodic mapping of their distribution and numbers. It is the last leg of the Atlas, with two winter visits over the coming three months and then two summer visits next year, and I find myself in an area of open farmland and small woodlots up near Shipdham. This is a place that I have not visited before.

As my two-hour mapping exercise continues so I come to realise just what an excellent piece of Norfolk countryside this is. A large flock of Yellowhammers and Skylarks is feeding on some stubble, a rare sight these days, and Lapwings lift from a piece of damp pasture upon my approach. It is the hedgerows that surprise me most of all. Although they have been cut back hard, they rise to a decent height and hold a larder of berries and fruits, attracting in Fieldfares, Blackbirds (by the dozen) and various finches. They also carry last year’s nests, including a surprising number of Chaffinch and Goldfinch nests, neatly constructed in the forks of the taller shrubs, alongside those of Wren, Blackbird and Wood Pigeon.

A soft whistling note alerts me to the presence of a Bullfinch, old billy black cap, and then I spot him just ahead of me above the bramble. He is not alone; two other Bullfinches slip from the hedgerow, their striking white rumps evident as they fly. The Bullfinch is a wonderfully engaging bird, with its little black cap, pinky-red breast (in the male) and stubby little beak. I used to watch them as a child, feeding on the seed heads of dandelion and sorrel with delicate precision. They are birds of scrubby woodlots and thick hedgerows, often overlooked despite their colourful attire. Both the song and the call are subtle and easily missed.

Our Bullfinches are largely sedentary in habits but they will make small local movements out from favoured woodland sites to search for seeds in nearby farmland. These movements are more pronounced in those years when Ash seeds, their staple food, are in short supply. Interestingly, the larger Scandinavian birds can make substantial movements in some years. This is such a year and several have been reported around the Norfolk coast. Bullfinch numbers have declined since the 1960s, most notably within farmland, and they are one of the birds that is often missed when doing Atlas fieldwork. To stumble across this trio of billy black caps has made my morning.

Thursday, 9 December 2010

Birds of a feather roost together


The bird table and hanging feeders are busy first thing in the morning, underlining the urgency with which many of the smaller birds need to replenish energy reserves lost overnight. Winter is a difficult time for small birds, the long nights and low temperatures placing strain on the small fat reserves these birds carry. If temperatures hover around freezing, or dip below, then these reserves are quickly depleted, something that can be a particular problem for our smallest birds, like Wren, Long-tailed Tit and Goldcrest. Research has shown that both Blue Tits and Great Tits lose some 5-10% of their body weight over the course of a typical winter night, possibly a lot more if the conditions are particularly poor.

Heat loss is, in part, dependent on where you choose to roost. Pick somewhere warm and you’ll be able to maintain your body temperature at a safe level more easily than if you pick somewhere cold. It is for this reason that some of our birds will roost communally, seeking the warmth from street lighting (Pied Wagtails) or from huddling together in a nest box or roosting pouch (Wren, Blue Tit or Coal Tit). Others roost within vegetation, a behaviour which sees Long-tailed Tits form up in a line along a branch or stem, huddled together within thick cover and out of the wind.

The use of nest boxes for roosting is something that is easily overlooked, especially if the birds pile into the box just as it is getting dark. There are some records of observers witnessing these arrivals; in one case at least 60 Wrens squeezed into a single box, but the behaviour is likely to be more common than these occasional reports would suggest. It is for this reason that the British Trust for Ornithology (BTO) has asked us to look at our nest boxes over the course of the next few weeks. If you take a look at your nest box one afternoon and then another the following morning, you should be able to tell if it has been used as a roost. This is because you are likely to find fresh droppings come morning if a bird has used the box overnight.

You might be fortunate enough to have a nest box camera attached to your box. If so, turn it on each evening to see if a bird is using the box for roosting. More details will shortly appear on the BTO website: www.bto.org/gbw. Other birds form roosts that are more obvious. Starlings, for instance, gather together in very large flocks, which pulse and whirl about the sky prior to the birds dropping down and into the chosen site – often a large conifer.

Wednesday, 8 December 2010

We are not alone


I watch her some mornings as she moves across the wall; her eight, stiletto-tipped legs find unseen purchase on the plaster, gravity-defying and assured in their hold on this world that exists in a vertical plane. Her body is just a few millimetres in length, darkly patterned and with an arc of tiny glistening eyes on the top of her head. I have not worked out which of our many spider species she is, in part because I do not wish to disturb her daily routine.

She is not alone, as other spiders lurk in the corners of this old house. Some are rarely seen and I suspect that they indulge in nocturnal scurryings long after we have turned in for the night. Others are chance encounters, seen briefly as they race across the carpet and dash under the sofa; big hairy beasts that spook our rather feeble hounds. Then there are the daddy-long-legs spiders, Pholcus phalangioides, that hang in untidy webs where wall meets ceiling. These fragile looking spiders gyrate their bodies if disturbed, the motion so fast that the spider becomes little more than a pale blur, an effective and surprising defence for something so small.

Despite the ungainly appearance Pholcus will tackle other spiders, including those from outside that have ventured into the house in late autumn. Any that touch her web are approached and it is then that the long legs come into play. They give her greater reach, allowing silk drawn from the spinnerets to be flung over another spider with minimal risk. As well as other spiders, Pholcus will tackle small moths and mosquitoes, both unwelcome visitors to many homes, and I sometimes spot the body of a White-shouldered House Moth, partly wrapped in her silk.

One of the reasons why this house is so popular with these spiders is its age, lacking the dry warmth of modern houses, with their central heating and double-glazing. Like other house spiders, Pholcus can survive long periods without water but even she must descend to find it from time to time. Her eggs are thought to be prone to desiccation and presumably cannot cope in a modern house.

I do not mind sharing our house in this way. Most of these other residents are innocuous enough and have little or no impact on our lives. The occasional visitor may go away with the impression that we are a little untidy, perhaps, but the scatter of webs and their delicate residents provides a sense of connection during these bleak winter months. We are sheltering together from the elements outside, a community of lives whose daily routines sometimes bring us into contact with one another.

Tuesday, 7 December 2010

What is our problem with rats?


With a reputation for spreading disease and for damaging foodstuffs, the Common Rat is regarded by most people as little more than a pest. Point out a rat to the wrong person and not only will they utter the most disparaging of responses, but they might even shudder and take a subconscious step backwards. Of course, our problem with rats is just that; it is ‘our’ problem and of our own making. We have cast the rat as villain because it interferes with (or is perceived to interfere with) our way of life.

There is no doubt that rats do damage foodstuffs, such as grain stored on agricultural premises, but if we are going to harvest and store food in this way, then we should not be surprised when some other creature exploits the opportunity being offered. Interestingly, the damage to foodstuffs comes primarily from contamination (with faeces, urine and hair) rather than from consumption, and rats do surprisingly little damage to the standing crop. Control measures tend to be focussed on killing rats or deterring them, rather than on the logical (though more expensive) option of properly excluding them from where we store our food. Rats also spread disease, notably leptosprirosis, but the risks to us are small relative to the other risks that we face in our daily lives.

Much of our problem with rats comes down to perception. The Common Rat is perceived as an invader, the aggressive Seventeenth Century colonist that ousted our ‘native’ Black Rat (a smaller and more delicate creature), but the Black Rat is itself a colonist (arriving with the Romans). It is also wrongly assumed that the Common Rat arrived here from Norway, an error perpetuated through its scientific name Rattus norvegicus. In fact, the Common Rat did not reach Norway until nearly half a century after it had first arrived here, most likely on a ship out of Russia.

Rats are perceived to be dirty, disease-ridden creatures, in part because of their association with the underbelly of society. Rats do well in urban areas; they establish colonies in our sewers, on the underground, alongside our inner city rivers and around our refuse tips. But this says more about us, about the rubbish and the waste that we create. The rats I see most often are those that inhabit the banks of the river running through town. These rats feed on the waste food dumped by passers-by, too lazy or ignorant to take their waste home. We have become a disposable society and it is our excesses that support the rats that we transported across the globe in our ships. Perhaps their presence says more about us than it does about them.

Monday, 6 December 2010

Tufted duck gather for the winter


Good numbers of Tufted Ducks are gathered on the flooded gravel pits near home. Scattered among the more abundant Coot they prefer the quieter corners, away from the fishermen and their Sunday afternoon radios, tuned to the football. They are our most abundant and widespread diving duck, quite capable of sustaining dives down to 14m in search of food, something that gives them access to waterbodies unsuited to dabbling duck like Mallard and Shoveler. Tutfed Ducks are, therefore, a familiar sight during the winter months on many of the county’s flooded gravel workings.

Some of these Tufted Ducks are likely to be the same individuals that were here during the summer, perhaps even the individuals that managed to raise a family on the site. Many others, however, will have come from elsewhere. Birds from Fennoscandia and Russia may have arrived here as early as July, initially favouring much larger waterbodies (like Abberton Reservoir) where the birds gather to moult. Because Tufted Ducks breed so late in the year, with eggs often hatching during July or even August, many of the birds gathering to moult will have been males, the females remaining elsewhere to tend to the needs of their growing chicks. Smaller numbers of females may have arrived in August. Most of these birds remain here for the winter, dispersing from the favoured large reservoirs to smaller waterbodies, like the pits just south of Thetford. They will only move on if the waterbodies freeze over, halting access to the molluscs and invertebrates that they favour.

The numbers wintering here are dwarfed by the vast numbers that winter around the Baltic or on the Ijsselmeer in the Netherlands. Some winter further south, reaching the Black Sea and the Mediterranean. Although our breeding population has undergone a period of substantial growth, no doubt helped by the increasing number of gravel workings being flooded, wintering numbers have been fairly stable. This might underline the contribution of winter immigrants from elsewhere. One interesting aspect of the winter flocks is the dominance of male Tufted Ducks. On average, the males outnumber the females by 1.4 : 1, a reflection of the late breeding season and the early movements of the males. The males are instantly recognisable, with their black bodies and white flanks. Females are less striking, with dark brown bodies and paler brown flanks. A flock of ‘Tufties’ is always worth a scan with your binoculars, as it can sometimes hide one of our less common diving ducks; perhaps a Scaup or even a Lesser Scaup. I do like to see the Tufties on our local pits, since they seem more in keeping with the image of a wild duck than the usual Mallards.

Saturday, 13 November 2010

Nervous plovers give a stunning show


The Golden Plover flock is anything but settled and it seems likely that they have been harassed by a Peregrine or other raptor during recent days. Several hundred of these beautiful waders shuffle nervously on the exposed mud of one of the lagoons at Norfolk Wildlife Trust’s Cley reserve. A multitude of gleaming black eyes alert to danger, it only needs one bird to take to the wing and the rest of the flock erupts with a clearly discernable rush of wings. The flock rises sharply, forming a coherent mass and taking on a life of its own, pulsing and twisting in the air, flicking from gold upperwings to a flash of white underparts. It is easy to see how a would-be predator might find it difficult to single out a victim. Moments later, the flock having circled, and birds begin to drop back down to the deck. Each time the flock goes up there are groans from the other end of the hide. A juvenile American Golden Plover was keeping company with this flock yesterday and some birdwatchers are keen to pick it out from its mass of slightly larger, warmer coloured European relatives.

When you see the spectacle of a decent flock of waders on the wing, jinking and twisting through the air, it is easy to see their appeal. While some waders can be considered beautiful in their own right, the sight of many hundreds or thousands of individuals collected into a flock is truly amazing. They are not the only flock present today, with several hundred sleeping Teal, many dozen Wigeon and a sizeable number of Black-headed Gulls, but they are the only spectacle. Every now and then the panic of the plovers triggers the gulls to take flight. But with the gulls there is no synchrony, no sense of individuals working together in unison. Instead, the gulls merely give a ragged show – a random flurry of white, lacking direction and purpose.

Flocking provides a number of benefits, including those related to predation risk. If you are part of a flock then your chances of being the target of a predator are reduced. Having others of your kind with you when feeding means that while you have your head down searching for food, another individual will almost certainly have its head up scanning for predators. Golden Plover often flock with other birds, especially when they are feeding, and they can often be seen in the company of Lapwing or Black-headed Gulls. While the smaller plovers may lose the odd piece of food to a larger gull, again there are the benefits of having more eyes to watch out for predators. And the benefit for us? A spectacular show.

Friday, 12 November 2010

Bearded Tits much in evidence


Despite its name the Bearded Tit is not related to the familiar Blue and Great Tits that we see in our gardens. In fact, it is not entirely clear where it should be placed in terms of avian relatives. Previous studies had suggested that it should be regarded as a parrotbill but more recent work implies that its affinities are more closely linked to the larks. Of course, this matters little to the bird itself, nor to most birdwatchers. It shows a number of similarities to the tits in terms of appearance and it is certainly equally appealing. Interestingly, the latest revision to the English names ascribed to our birds has seen a reversion to a rather charming old name for the bird, namely Bearded Reedling. The male sports a rather handsome black ‘moustache’ and the species is associated with reedbeds so this could catch on. Certainly, it is a less contentious suggestion than some of those put forward for other birds – like Red-throated Loon (Red-throated Diver) and Mew Gull (Common Gull).

Two Bearded Reedlings have been seen on the local reserve over recent weeks, a rather welcome addition to a site on which they have never bred. Their appearance comes at a time of the year when, following a successful breeding season, many individuals undertake significant dispersive movements. Such movements are one reason why the species has been able to recover from a period when it looked as if it would be lost from Britain as a breeding species. During the winter of 1947, following loss of suitable breeding habitat, widespread persecution from egg collectors and a run of cold winters, there were thought to be fewer than five breeding pairs in the country – a single bird in Norfolk and 3-4 pairs at Minsmere.

Cold winters still have a big impact on the population but the combination of strong powers of dispersal and high levels of productivity help them bounce back rapidly. Not only do Bearded Reedlings compress their breeding attempts into an unusually short period, they often overlap successive attempts, enabling them to produce good numbers of chicks. The chicks leave the nest before they can fly and become independent at just 20-25 days of age.

With good numbers of these birds moving around the countryside, now is a good time to catch up with them. Sites with large reedbeds, such as in the Broads or along the North Norfolk coast, are well worth a visit. Although the cinnamon-brown colouration can make them difficult to spot they can be surprisingly approachable. Their characteristic pinging contact call often reveals their presence, as pairs or small parties work their way through a reedbed in search of food.

Thursday, 11 November 2010

Celebrating the bird observatories


Just over a decade ago I was fortunate enough to spend a few days on Heligoland, a North Sea island off the coast of Germany. It is a bizarre place, with a series of tax-free shops around the small harbour to serve day-tripping German tourists, a conference centre and various houses and apartments. The rest of the island is a mixture of rough ground, old fortifications and dunes. Importantly, however, it is the place where Heinrich G├Ątke spent 50 years studying the migration of birds and where he established his ‘vogelwarte’ or bird observatory. The observatory, a small building and well-vegetated ‘garden’, sits just below the ridge of the island and pulls in many migrant birds. Heligoland’s position in the North Sea means that it attracts vast numbers of migrant birds, allowing researchers and bird ringers to study bird movements in great detail.

The notion of the bird observatory arrived in Britain in the early 1930s, with the establishment of Skokholm Bird Observatory by the ornithologist and author Ronald Lockley. This small island observatory, located off the southwest coast of Wales, attracted the interest of leading ornithologists and it was not long before other observatories were opened at suitable sites elsewhere around the British and Irish coasts. Soon after the war the BTO set up a committee to coordinate the research efforts of the observatories, helping to standardise recording methods and to pool the new information that was being collated. The results from these early years appeared in a new journal, named Bird Migration, which makes fascinating reading and is something I dip into from time-to-time. The collective reports summarise each autumn and spring migration, charting arrivals and departures for a wide range of species.

Even though interest in the observatories waned a little during the 1960s, with interest turning towards what radar studies were revealing about bird migration, there has been a real resurgence of late as observatories attract a wider audience of birdwatchers and naturalists, keen on learning and experiencing migration in its many forms. Today, 18 observatories form the Bird Observatories Council, with Holme in Norfolk and Landguard in Suffolk our nearest ones. There are others that operate outside of this network, generating more information on bird movements.

The ability to catch and ring migrating birds in a systematic way provides an opportunity to look at how migration patterns may have changed and the extent to which such changes may reflect wider changes in bird populations. Many of the observatories also operate moth traps and collect information on the other wildlife on their sites. All act as a focus for local, regional or even national interest in wildlife and it is wonderful to see them doing so well.

Wednesday, 10 November 2010

Riverine


Having spent much of the day in the house, the weather outside a succession of heavy showers, I feel a need to go out and get some air. It’s late afternoon and a suggestion that the sun might be breaking through gives me the impetus that I need and I head down to the river. The walk is brisk, easing the stiffness from my joints and clearing the day’s paperwork from my mind, and I cut through the still dripping wood and strike out towards the meadow.

I like this bit of the river. It is off the beaten track and you have to pick your way through rank vegetation to rediscover its meandering course. The scattered Alders chart the river’s route through the meadow and I am soon settled on the bank, screened on three sides by nettles and rough grasses. Because movement through this bit of meadow is difficult and noisy, it is impossible to approach any animals or birds without scaring them away. I find that the best approach (as it is in many habitats) is to find a suitable spot in which to settle and to wait patiently for the wildlife to approach you.

I have not long been settled when the sun fades behind a thickening blanket of cloud, heralding the approach of another squally shower. At first the smooth surface of the river reveals just a few spots of rain but then, increasingly, the ripples coalesce as the rain’s intensity increases. With several layers of clothing, including a goose-down jacket and a waterproof, I will be dry enough but I hunch forward, drawing my legs up to protect my camera bag. From under my hood I still have a good view and watch the approach of a male Muntjac. He has not seen me, or if he has, he has mistaken me for a large grey mass, perhaps a rock or unmoving pile of decomposing vegetation. It is wonderful to be able to watch unseen, the deer browsing intermittently as it passes by just a few feet from me.

The rain strengthens further, becoming a rush of hail, noisy on my hood and reducing the visibility such that I lose sight of the Muntjac. Just as quickly as it arrived so the hail halts and, soon after, the rain too. A Grey Heron drifts in on broad wings; legs held below it drops to the opposite bank. It seems unsure but I cannot tell if it is my presence or the fact that there is no obvious route for it to take into the water, such is the growth of emergent bankside vegetation. The heron lifts itself away with strong strokes and the river is mine alone.

Tuesday, 9 November 2010

Hail the Woodcock pilot!


For two weekends on the trot I have been on the coast at first light to watch the arrival of migrating birds, picking out my first Bramblings and Fieldfares of the winter from many other newly arrived individuals. A persistent theme of both weekends has been the numbers of Goldcrests, arriving exhausted from their recent sea crossing and keen to feed up on small invertebrates gleaned from trees and shrubs.

Goldcrest, by Mike Toms

I am in awe of these tiny creatures. Weighing no more than 7g, they are one of the lightest birds to undertake regular sea crossings when on migration. This feat can be considered all the more remarkable by the fact that they carry little in the way of fat reserves and, with little fuel with which to make the journey, it is little wonder that they arrive exhausted. Equally remarkable, to my mind at least, is that these diminutive birds are able to survive long winter nights and low temperatures by burning up energy reserves that may see them lose a fifth of their body weight over a single night.

Our Goldcrests, those that I encounter in the forest throughout the summer months, are largely sedentary in habits. With the possible exception of those from more northerly parts of Britain, these individuals spend the winter here, with some moving into gardens to take advantage of the fat products that many householders now provide. Those from elsewhere in northern Europe, notably northern Scandinavia and Russia, move south or southwest in autumn and it is these birds that have been arriving along the Norfolk coast over the last few weeks.

Many are young birds, perhaps reflecting a good breeding season, but maybe also underlining their short lifespan and the high degree of turnover of individuals within the Goldcrest population. We handled a good number at one of our coastal ringing sites the other day and it was clear that some had just arrived, being of low weight and low fat score (we can score the amount of fat on a bird because the fat is carried in a pit on the chest and along the belly), while others had been in for a couple of days and had already fattened up.

The arrival of Goldcrests is now just about over, as is the case for many of our other winter visitors and passage migrants. The arrival of Goldcrests is often linked to the arrival of Woodcock and Short-eared Owls, something that might explain the folk name of ‘Woodcock pilot’ given to the Goldcrest. Among wildfowlers it is sometimes said that the Goldcrest hitches a ride in the plumage of migrating Woodcock, but it is similarity in the timing of their autumn movements that really underpins the association.

A torrent of otters

It has been nearly five hours of patient waiting, stood on the bridge, watching the river and listening for the telltale calls that would give away the otters’ presence. I’d seen them here earlier in the week, not well, but this weekend was my opportunity to get what I hoped would be a proper view.

Over the past 15 years I have had just three encounters with otters on this particular stretch of the river, so a series of reports of a family party was a clear draw. Patient watching, three hours before dusk last night and two from first light this morning, affords solitude, your senses alert to the wildlife around you but your mind clear to wander where it may. I’ve seen and heard many other creatures but not the otters, not yet at least.

Then a noise upriver suggests they are coming – squeaking calls and splashing sounds – and I feel myself tense with anticipation. They come at a rush, a torrent of otters moving quickly through the water close to the far bank. It is purposeful, with a mother otter leading four cubs under the bridge and out of sight. This is not the encounter I’d envisaged, one with young otter cubs playing in the riffles and pools. The sound of bankside vegetation shows that they have left the water, moving through the thick cover and into the wet woodland that pushes broodingly up against the river. They are heading downstream, perhaps to the old swimming hole, and I decide to reposition myself further along.

The otters are moving surprisingly quickly and are back in the water ahead of me – so much for getting ahead of them. Big, globular bubbles float on the surface as the cubs roll and dive and play. I fire off some shots on my camera – the light not too good but I hope just about good enough. I can, at least, delight in seeing them at play. A litter of four cubs is particularly good (two or three cubs is the more usual number) and these feisty individuals must be at least 15 weeks old.

The otters have spotted something, the mother alarming with a short and rough ‘hah’. It’s not me but a large black dog on a lead that, having seen the otters, lets out a bark. This is enough for the otters and again they take to the cover of the wood, all the while working their way downstream. I follow their lead and am rewarded a few minutes later by the sight of them slipping back into the water just above the swimming hole. Soon it is all over, the otters out of sight, but a magical few minutes nonetheless.

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

Solitude


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

Bonxie


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.

Saturday, 18 September 2010

Changing waterfowl require greater understanding


The latest review of waterbird populations in the UK makes interesting reading. At first glance it suggests contrasting fortunes for many of the species with which we share these islands. The review, jointly published by the BTO, RSPB and JNCC, stems from the efforts of some 3,000 volunteer counters. These volunteers participate in the synchronised monthly counts that take place across our many inland and coastal waterbodies.

While some species reached new ‘highs’ in terms of their population levels, others reached all-time lows. An examination of the ‘winners’ and ‘losers’ reveals that many of the ‘winners’ are introduced species whose naturalised populations continue to expand. These include Egyptian Goose, Mandarin Duck and Barnacle Goose. However, in with these are genuine colonists like Little Egret, a species expanding north on the back of global climate change.

The numbers of some species reflect breeding conditions elsewhere, the UK being a wintering ground with little or no breeding population of its own. A poor breeding season elsewhere may see fewer birds available to make the journey to our shores. The recent downtown in wintering numbers of Bewick’s Swans was once thought to be linked to a contraction eastwards in the wider European wintering range. However, recent research has revealed a decline in the overall population rather than just a shift in distribution. In contrast, our population of wintering Whooper Swans has continued to increase, with most of our visiting Whoopers arriving from Icelandic breeding grounds. The nature of the survey also enables the volunteer counters to gather information on breeding success for some species. In the case of the Whooper Swan, cygnets accounted for 16.8% of the birds present, slightly up on the previous winter.

The estuaries around Britain & Ireland are important wintering sites for many wading birds and these are also surveyed by the volunteers. Again fortunes appear mixed, with some notable increases seen in Avocet (a real conservation success story), Grey Plover and Sanderling. Balanced against this is the apparent news that Ringed Plover and Dunlin have both hit all time lows. Britain has eight sites of international importance for Ringed Plover but, while the decline might seem worrying, news of increasing numbers at sites elsewhere in Europe (notably The Netherlands) suggests that what we are actually seeing is an eastward shift in the core wintering range, perhaps linked to a run of mild winters.

Taken as a whole, this report highlights the need to monitor the changing fortunes of these birds at a much wider spatial scale, since a decline here may not mean that the population is falling, merely that it is now wintering elsewhere. Fortunately, our knowledge of waterbirds is increasing, placing our understanding into a wider context.

Friday, 17 September 2010

All in the eye


I have been reading Carry Ackroyd’s book about the Fens and the influence it has on her work as a printmaker. The subtitle of the book ‘Landscape Change John Clare and Me’ bears testament to the hold that this unique landscape has had on artists and writers down through the years. John Clare, often referred to as the peasant poet, documented the loss of ancient countryside to the changes he saw in farming practices. Working as a farm labourer, he was connected with the land in a way that other poets writing on natural history could never be; this shows through in his detailed observations and closeness to the subjects of his lines.

A key element of Carry’s work is the natural history that sits within her fenland landscapes. She is not just documenting the land but also the creatures that are an integral part of it. In this way, her work is refreshingly different from a traditional view of ‘wildlife art’, with its simple presentation of animals and birds divorced from their surroundings. In fact, Carry is part of a wider movement away from the tired images of lions, elephants and eagles that were once the mainstay of wildlife art. For me, art should stimulate an emotional response from the viewer and wildlife art should be no different. Whether it is the sense of space that comes from Carry’s fenland views or the tension of Andrew Haslen’s Brown Hares, crouched low within their Norfolk forms, good wildlife art connects you with the landscape or creature that you are viewing.

I have always been influenced by the tones of nature, be they the purples of the autumn heathland where I grew up or the olive-green of hares within a winter field. It is these qualities that reach out to me from prints and paintings, along with subtle shapes that bring life to birds or animals captured in two or three dimensions, shapes that echo my own recollections of seeing these creatures in the field.

Art is very much about personal taste; being able to view a group show in a gallery provides the opportunity to discover what it is that you most connect with. As well as the grand opportunities provided by the art marquee at the BirdFair in August or the SWLA show in London in September, there are local galleries – notably at Cley, Glandford and Lavenham – where you can see a wide range of art by wildlife artists.

The Natural Eye, the 47th exhibition of the Society of Wildlife Artists, is being held at the Mall Galleries, London from Wednesday 22nd September until Saturday 2nd October. For more information, visit www.swla.co.uk

Thursday, 16 September 2010

A subterranean way of life


Rake through a piece of woodland leaf litter with your hand and you may well come across a cobweb-like mat of fine white threads. These are fungal hyphae; they are building blocks of filamentous fungi, thin cylinders that contain cell nuclei, mitochondria and other life-defining organelles. The fungal fruiting bodies familiar to us as mushrooms and toadstools are formed from hyphae and great empires of these threads carpet the soil and shroud the rootlets of trees and shrubs.

Fungal hyphae show certain similarities to the roots of plants, not least in that they absorb nutrients from their surroundings, acquiring resources to support growth and, ultimately, the production of the fruiting bodies that will disperse their spores. The hyphae also produce digestive enzymes, which digest the material in which the hyphae are growing. Most typically these enzymes digest cellulose – think of all the fungi you have seen growing on dead wood, but others digest keratin (hair and fur) or chitin (the material that forms the exoskeletons of insects). There are even fungi (in the broadest sense) that produce enzymes which can digest kerosene!

Many of our familiar fungi are associated with trees; rather than occurring loosely in the soil, their hyphal networks accumulate around the rootlets of certain trees and larger shrubs. Some of the hyphae grow into the rootlet, forcing their way between the tree’s cells. This association is not as one-sided as you might imagine, since it is not simply a case of the fungus attacking and feeding on the tree’s tissue. While the fungus receives moisture and nutrients from the tree (the latter most likely as by-products) the tree receives access to the soil nutrients being harvested by the fungus. The structure of this close association, the rootlet and the hyphae, is known as a mycorrhiza or ‘fungus-root’.

Knowledge of fungus-tree associations can be particularly useful when seeking to find or identify certain fungi. There are, of course, a number of species that are generalist in their habits, and which are associated with a number of different tree species, but others are rather choosy. Fly Agaric, for instance, seems to favour mature birch trees (invariably those of 15 years age or older) or, to a lesser extent, pines. However, other features probably also have a roll to play, notably soil pH, soil condition and how wet the soil is. The sight of fruiting bodies at this time of the year reveals the presence of fungi that exist beyond our gaze for the rest of the year. The weather seems to have been favourable this year and there is a rich crop of fungi to be found across the woods, heaths and grasslands of Norfolk.