Saturday, 19 September 2009

Stone Curlew gather on the heath

The heath echoed this afternoon with the calls of Stone Curlews, several dozen individuals of which had gathered together to lounge about and generally pester the local Rabbit population. To my mind, this is the best time of year to watch them; away from the breeding grounds they are less sensitive to disturbance and they are more active, flying low overhead and interacting with each other. One other benefit of watching them at this time of the year is the lack of any heat haze, a common problem during the summer months when you are trying to pick the birds out from the bare arable ground on which they are sat.

Thanks to the efforts of local landowners, managing their land in a sensitive manner, the Stone Curlew population has undergone something of a resurgence in the Brecks over recent years. Following a low point in the early 1980s, when fewer than 90 pairs nested, the population increased to in excess of 200 pairs in 2007. Breckland has always been the heart of the Stone Curlew population, with Stephenson – writing in the late 1800s – that ‘there is little fear … that its presence in summer will enliven the waste for many generations to come.’ Of course, much of the ‘waste’ has gone, and the birds now nest on the arable land which has replaced the heath and sheepwalk.

The Stone Curlew is predominantly a summer visitor, arriving on its breeding grounds from the middle of March. Interestingly, a few individuals have overwintered in the Brecks over the last few years at sites like Gooderstone and Hilborough. More typically, however, the birds depart for wintering grounds in southern France, Spain and North Africa during October. Prior to this (and typically from late July) the birds gather together on traditional roosting sites, with newly independent young loafing about alongside moulting adults. Come evening, the birds disperse to other sites to feed. This makes late afternoon a good time to visit, the birds more active than earlier in the day, and with more chance of seeing them in flight low overhead.

It is a privilege to see these birds so close, and in such numbers. There is something of the prehistoric about them, most probably their huge bright yellow eyes and angular lines, and I could watch them for hours, as they tackle the Rabbits for no obvious reason or fly up at a Rook that has strayed too close. But as daylight starts to ebb away and the birds get ready to disperse, I know that it is time for me to head home and to leave my Stone Curlew watching for another afternoon.

Friday, 18 September 2009

Orb webs adorn the garden

This is the time of the year when orb web spiders are at their most obvious. Several have cast their beautiful spiral webs across the corners of our windows, with others strung between the branches of garden shrubs or across the door of the greenhouse. In the centre of each web sits a female spider, Araneus diadematus, the familiar Garden Orb Web Spider, head down and motionless. On the rare occasions when the web appears empty, the telltale signal thread running from the centre of the web to a suitable nook in the brickwork soon reveals her location. Should an insect become caught in her web she will rush down the signal thread, take up a position in the centre of the web to determine where the victim is caught and then dash along the appropriate radial thread to deliver a fatal bite.

The patterning on the back of the female resembles a white cross and this may explain why this particular spider was the object of veneration during the Middle Ages. By now, in early September, she will have completed eight moults, shedding her exoskeleton to grow in size and reaching just over a centimetre in body length. The smaller male, who will be travelling around in search of a mate, undergoes just six moults. Understandably, the smaller males make a careful approach to any suitable female, the risk of being eaten increasing as the season progresses. The male very gradually moves forward onto the female’s web, attaching a safety line that will allow him to drop rapidly from the web should the female lunge at him. Each time the female attacks, so the male has to begin all over again, the process tedious to all but the most patient observer.

The male makes his courtship all the more complicated by the fact that he seeks to lure the female onto a special mating thread. If he succeeds in getting her onto the thread then she will signal her compliance by hanging motionless, head down. This affords the male the opportunity to insert one of his palps into her reproductive organ; the other palp, however, requires yet more of the gradual and patient courtship. After mating, at some time during September or October, the female will leave the web to lay her eggs somewhere close by. The eggs, which are held together in a tight solid mass, may number up to eight hundred and are collectively wrapped in rough silk, sometimes camouflaged with small bits of debris. By now the female will be close to death; emaciated she takes up a position next to her egg sac, where she will remain over the last few weeks of her life.

Thursday, 17 September 2009

In search of the wild

A recent taster for a new television series about the ‘wild’ has set me thinking about how little wilderness remains, not jut here within our crowded island but more widely across the globe. With the advances in travel and technology there are few, if any, places that we cannot reach. In turn this means that there are few places that have not, in some way, been touched by Man and our activities. Remote coastlines, unvisited by Man, are still the recipients of our waste; plastic and other refuse that has drifted ashore from the sea. Inland valleys, inaccessible except from the air, may have been contaminated by chemicals carried in the rain, a residue of industrial pollutants now spread across the globe on vast circulating weather systems.

Our relationship with wilderness is important; it defines who we are and provides a measure against which we can judge our place in the World. One of the most important components of wilderness is the sense of scale, particularly given that so many of us now live within urbanised environments. The urban environment, with its narrow streets and ever-taller buildings, has shortened horizons and, consequently, removed the opportunity for people to experience (as the novelist Wallace Stegner described) ‘a sense of bigness outside themselves’.

There is another, somewhat different, side to the wilderness that has long fascinated me; this is the sense of the wilderness (or the ‘wild’) as some dark and menacing place outside of our control. If you look at literature you will often see reference to the wild described as a dark forest or a wood, within which strange and terrifying creatures exist. The association between the ‘wild’ and the ‘wood’ echoes down through the ages from a time when our ancestors first began to clear our ancient woodlands. Both ‘wild’ and ‘wood’ are thought to have developed from the same root word ‘wald’ and the Teutonic word ‘walthus’ (forest) entered Old English as ‘weald’,’ wold’ or ‘wald’. These words were used to denote both a ‘wooded place’ and a ‘wild place’, cementing our association between the wild and the wild wood, as used by Oliver Rackham.

It is easy to dismiss the wild, the tracts of land that lie outside of our direct influence, and to think of them as waste; land that could be brought under the plough to meet our ever growing demands for food and materials. Yet the wild has a place, not just for the vast number of other species it supports but for our own wellbeing. We should use the wild to question our sense of being, to test our perception of self-importance against the bigger world outside of ourselves.

Wednesday, 16 September 2009

Regular watching pays dividends

Spend any time watching garden birds and you’ll soon realise that there is a great deal going on in your average garden. However, what you see is merely scratching the surface of what is really happening and much remains hidden from view because, to our eyes, most individuals of a given species look alike. The handful of Blue Tits that you see daily at your hanging feeders may, in reality, be many dozens of different individuals, which use your garden on a daily, weekly or seasonal basis.

As a trained and licensed bird ringer, I have been able to appreciate the numbers of individuals that may make regular use of a garden feeding station. Even so, I still need to catch the birds regularly to discover which individuals are still popping in for a feed. One way in which it is possible to build up a more complete picture of the lives of individual birds is through colour ringing, a technique by which licensed bird ringers fit birds with unique combinations of coloured rings. Once fitted with such rings a bird can be identified as an individual without the need to recapture it.

Colour ringing is best used for targeted projects, seeking to look in detail at a population of birds within a given area. This might be at the scale of the Blackbirds using a series of gardens in Holt (as is the case for one Norfolk-based project) or it might be at the scale of Black-tailed Godwits moving between Iceland and various sites in Britain and continental Europe (research being carried out by staff at UEA).

Looking in detail at a particular population invariably adds to our knowledge, revealing more about behaviour, ecology and survival. Colour ringing of birds has, for example, been used to look at breeding behaviour, highlighting which birds hold which territories and with whom they breed. At the same time it can change your perception of the numbers of birds that make up your ‘local’ population. Colour ringing of Great Spotted Woodpeckers at Croxton, just on the edge of Thetford Forest, has been taking place over the past six years. Some 63 different individuals have been colour ringed at the feeding station in this time and resightings by the site’s owner have revealed much about how these local birds are using the feeders. One female visited the feeders almost every day for five years, while another was a regular visitor for three years, only to disappear and then return two years later.

Colour ringing also enables members of the public to report any colour-ringed birds that they may see. Simply contact the British Trust for Ornithology’s ringing scheme ( and let them know what you have seen and where.

Tuesday, 15 September 2009

The Garden by Night

At night the garden becomes a very different place, the darkness shortening local horizons and the shadows shifting shapes and forms into unfamiliar contortions. Despite the darkness, I never find the garden or its shadows threatening. Instead it feels comforting, especially so on the last few warm nights of late summer, when a low cover of cloud deepens the shadows and softens the nocturnal sounds of this urban area. In a way the garden feels more private, less exposed and I am free to wander with my torch, searching out the army of small creatures that emerges with the setting of the sun. Dark brown spiders, almost black and somewhat flattened in their appearance, appear on the fence panels and the shed. They come in a range of sizes and it is interesting to see how they have divided up the vertical surfaces between them – the larger individuals well spaced, the smaller immatures less so. Examined more closely, their eyes burn bright in the beam of the torch and the subtleties of their colouration become clear.

Large slugs, pale mottled in appearance, leave trails of glistening slime across the patio that can be traced back to the shelters where they have spent the daylight hours, unmolested by birds or intrusive gardeners. Then there are the snails, also moving about the garden on trails of slime. Many of these have spent the day under the lip of the wall, seemingly not as secure from predators judging by the number of smashed shells left by the hardworking Song Thrush.

Moths buzz the light of the torch, while others can be seen working the last of the summer’s flowers in the cottage garden-inspired beds. Some of these moths are immigrants, such as the Silver-Y’s which have appeared in smaller numbers this year. Others are resident, many of which feature frequently in my moth trap on the nights that I run its bright bulb, tucked up against the wall to shade the neighbours. On warmer nights the number of moths in the trap is truly amazing, as is their variety of forms. Large stocky underwings sit alongside Setaceous Hebrew Characters, Garden Carpets and more delicate thorns, beauties and pugs (the names of our moths are a real delight).

Elsewhere in the garden there is a Speckled Bush Cricket. I cannot see it, since its call is too high pitched for my aging ears, but my bat detector picks up and amplifies the sound. The soft chirp of the male is intermittent but the detector suggests that it is sitting in the apple tree that overhangs the garden. From here it is calling for a mate, one of the few noises to break the nocturnal stillness.

Monday, 14 September 2009

House Martins remain a bird of mystery

The soft, dry-sounding, ‘priit’ calls of House Martins provide the soundscape to my weekend, as dozens of birds wheel and hawk for insects in the air above me. These robust little birds have a delicate appearance, less showy than the Swallows with which they share the skies and certainly not as exuberant as the laddish parties of immature Swifts that have, by now, mostly left the country. As the martins twist and turn, taking insects above the acres of pasture over which I am walking, so their large white rumps can be seen, foreshortening the bird’s appearance even further. I’d imagine that these individuals have finished breeding and are now in the first stages of an autumn migration that will take them south over Europe and the Mediterranean, before entering North Africa to face a crossing of the Sahara.

Autumn migration begins in late August but, with some birds still feeding young in late nests, it can extend through into October. Records from our east coast bird observatories show a peak in autumn passage during September. It is amazing to think that our House Martins are part of a much bigger European population, with an estimated 90 million birds crossing the Sahara over a period of just a few weeks. This ‘super population’ of House Martins moves on a broad front, with birds initially crossing the Mediterranean from Gibraltar east to Israel. Those from Britain migrate down a route towards the western end of this wave of birds, ultimately heading for wintering grounds in West Africa.

The exact location of these wintering grounds remains something of a mystery. One of the reasons for this is that, despite the sheer number of birds involved, House Martins are not seen regularly in big numbers in Africa. This may suggest that they winter over the vast belt of tropical forest that sits across the region, hawking for insects above the canopy and out of view of researchers and birdwatchers. This lack of knowledge is in contrast with what we know about the Swallow, vast numbers of which roost communally in African reedbeds. Here the birds can be caught and ringed by researchers, who not infrequently find individuals bearing British or European rings. Fortunately, the efforts of bird ringers have at least revealed the autumn migration of our House Martins south across Europe, providing us with a better understanding of their movements than was the case back in the time of Gilbert White. White was fascinated by the autumn ‘departure’ of our swallows and martins, but was of the opinion that the birds spent the winter here in a state of torpor. Now we know different, but we still don’t know everything about House Martins.