Saturday, 25 June 2011

Keeping things in proportion

It seems that many of us still have a problem with birds of prey; not a real, material, in your face kind of problem, but one of perception. The latest illustration of this came in the form of a letter from Hampshire, accompanied by a newspaper clipping with a stunning picture of a Red Kite and a headline that ran ‘School bans playing outside after Red Kite attacks on pupils.’ It appeared, so the rather brief article implied, that school children were ‘being ambushed by the birds of prey.’ The writer of the accompanying letter had clearly taken this article at face value and was concerned that the reintroduction of large birds of prey was putting the lives of small children at risk.

In Medieval times the Red Kite would have been a common sight over much of the English countryside, the bird also making a living in some of our larger cities where it could scavenge from the detritus of city life. As sanitation improved so the kites were lost from the built environment. Soon after they began to decline in rural areas, as levels of persecution increased alongside a growth in the number of shooting estates. The species was lost from England in the 1860s but did (just) cling on in Wales. With levels of persecution much reduced over recent decades, the decision was taken to reintroduce the species to its former haunts and work began in 1989 to make this possible. Today, the Red Kite population is in recovery and growing numbers have seen greater interaction with people.

The Red Kite is primarily a scavenger, feeding on carrion, but it will take small mammals, amphibians, small birds and various invertebrates. It is not, however, a threat to small children! In parts of the kite’s now expanding range, householders and landowners deliberately provide them with food; one kite feeding station in Wales is a huge tourist attraction. This something that could explain why the kites might have been attracted to playground scraps, perhaps with the school children even attempting to feed them by hand, throwing or holding up food.

Whatever the reason behind the incident, it underlines an innate fear that many of us still have of wild creatures. Being frightened might seem surprising, particularly given that we don’t have any large or dangerous predators left in Britain, but I suspect it is really a fear of the unknown. If you don’t know that a Red Kite is primarily a scavenger, that it eats lots of worms and is not going to steal your child, then you may be unable to shake off that fear. Maybe things will improve as more people get used to seeing the kites around.

Friday, 24 June 2011

A rustle in the bushes

Wildlife watching is not always about the watching. In many instances it is about listening: the soft call of a female Chiffchaff off her nest, the heavy buzzing of a drone fly or the high-pitched purring of a Roesel’s Bush-cricket. Listening can be particularly important when you are trying to catch up with something that happens to be in thick cover. When I am out looking for nests, gently tapping likely vegetation with a lightweight stick, I am listening for the telltale sound of a bird as it slips off the nest. Some leave quietly, with just the slightest sound as they brush through the vegetation, while others leave with far less grace.

Common Lizard, by Mike Toms

I use my hearing a great deal when I am out looking for reptiles. Even though they are silent in terms of vocalisations, each makes a particular sound as it moves through dry vegetation. For instance, the sound of an Adder moving through dry bracken is very different from that of a Common Lizard going over the same ground. While the Adder moves with a long, sweeping sound, the lizard is more rapid, covering the ground in a series of short, broken, sounds.

Both of these reptiles require a slow and patient approach if you are to get good and prolonged views of them. Slow movement, with careful and gentle placement of your feet, is essential as they are easily scared off. One of my regular sites for both Adders and Common Lizards is also favoured by dog walkers and family parties, all seemingly oblivious to the reptiles with which they share the site.

While the Adders are most often encountered in the forest, I have found Common Lizards to be more widespread and to occupy a greater range of habitats. Early in spring, and again in late autumn, Common Lizards can be found sunning themselves in open spots close to thicker cover. Each is seeking to double its body temperature, taking it up to the optimum operating temperature of about 30 degrees. During the warm summer days the lizards can reach this temperature rapidly, taking only a few minutes, which makes them more difficult to find. Cool and cloudy days promote basking and, if punctuated by brief periods of bright sunshine, are great for lizard photography. Under the hottest conditions lizards will retire altogether. Although warmth is clearly important to the Common Lizard it is worth just noting that this lizard is one of the most cold-tolerant reptiles in the world.

The challenge of getting close to our snakes and lizards is part of the attraction but it does require patience and a good ear for what is going on in the vegetation around you.

Thursday, 23 June 2011

Putting a price on wildlife

The recent publication of the UK National Ecosystem Assessment (UK NEA) has left me with something of an uncomfortable feeling. While the NEA should be rightly applauded as a comprehensive overview of the state of our natural environment, it has also effectively put a price on that environment and its component parts, which is something that about which I am less certain.

In some respects the NEA’s attempt to assign a value is a good thing. For too long decision makers have underestimated the true value of the environment and the services that it provides to our way of life. If the value of the environment is underestimated then there is a real danger that it will be lost or overexploited because its worth cannot be accurately compared against something else, something that does have a measurable and, therefore, defined economic value. Take the value of bees and other pollinators, for instance. The NEA report suggests that the presence of these pollinators is worth £430 million per year to British agriculture. Decisions made on the control of invertebrate pests through the use of broad-spectrum insecticides, which might impact on non-target pollinators, can now use knowledge of the value of pollinators to better interpret potential costs and risks. Other ‘ecosystem services’ that have been given a monetary worth include the amenity benefits of living close to rivers, coasts and other wetlands (valued at  £1.3 billion per year) and the health benefits of living with a view of a green space (valued at £300 per person per year). You would hope that this would lead to better decision-making.

This is all well and good but here is the rub. Once something has a value it can be bought and traded, and its worth becomes a currency divorced from the reality of the thing itself. It is right that we should properly value the world around us but I believe that there is an inherent danger in seeking to address this value in purely monetary terms. Is giving the countryside and its natural processes a monetary value the only way that we humans can properly understand its worth? If it is, then the future seems rather bleak.

In some ways the NEA process has stripped away the true value of the countryside, further divorcing our rapidly urbanising society from the natural world around us. The only way to get decision-makers to make properly balanced decisions about the fate of the environment is for them to have experienced the natural world at first hand. They should be people who have spent time living within and exploring the very places they are taking decisions on. Only then will they have experienced the true value of the ‘commodity’ they are now trading.

Tuesday, 21 June 2011

Strong winds cause problems

The combination of chest waders and lifejacket is not the most flattering of outdoor looks but it has become my regular attire this summer. Once or twice a week I am out monitoring a reedbed population of Reed Warblers as part of what we hope will become an important long-term study. Thanks to the generosity of the landowner we are able to monitor the nesting behaviour and breeding success of a sizeable Reed Warbler population using a series of old gravel workings.

While many of our long-distance migrants are undergoing substantial declines, the Reed Warbler is currently showing an increase in abundance and so it has received rather less attention than is, perhaps, desirable. The Reed Warbler is an important host for the Cuckoo, a species which is in decline, and it is important for us to learn more about Reed Warbler populations and the extent to which Cuckoos use them. So far, this season has not been that good for the Cuckoos parasitizing our reedbed warblers. Some of the reedbeds on the site are rather exposed and the strong winds of late May resulted in many nests losing their contents, as the reed stems to which the nests were attached bent over in the wind. This resulted in the loss of some Cuckoo eggs and chicks. The Reed Warblers will try again though, as will the Cuckoos over the short time they remain in the country.

One aspect of our work that is of particular interest is the pattern of breeding attempts. Some authors suggest that Reed Warblers have three broods in a season, while others think that the three broods are actually three waves of breeding: the first and last being attempts by older birds (in effect first and second broods), while the second wave is made up of young birds (in their first year of life) who return to the breeding grounds somewhat later in the summer. To test this, we are attempting to fit rings to all of the chicks reared on the site to see if and when we recapture them in future years. In order to be systematic about the recapturing component of our work, we operate a series of nets in set positions, once every ten days.

Monitoring the nests also provides information on breeding success. Last year, for example, the number of eggs laid (3.67 per nest) was lower than the national average but the survival of the nests through to fledging was higher, so that the number of fledglings produced per breeding attempt was similar to that at other UK sites. Large-scale, long-term studies are uncommon, which makes our work particularly important. It is going to be fascinating to see what we discover over the coming years.

Blues lifted by the heat

The legacy of a warm start to the year has seen the early emergence of many of our butterflies and moths, with several species on the wing a week or more ahead of usual. One of the species to benefit has been the Silver-studded Blue, a stunning little butterfly that (within Norfolk) is restricted to a few areas of suitable habitat in the northern half of the county.

In Britain, the Silver-studded Blue is primarily a heathland species, with just three populations in the west of the UK using other types of habitat. In parallel with the tremendous loss of lowland heath, this blue butterfly has undergone a substantial decline in both numbers and range. The national pattern of decline has been mirrored in Norfolk, where the natural history records held by Gresham’s School document the disappearance of former North Norfolk colonies to land reclamation and afforestation. Fortunately, the species has shown something of a revival over the last two decades, much of which has been due to the efforts of volunteers supporting the work of Butterfly Conservation.

Our Silver-studded Blue populations are centred on Kelling Heath in North Norfolk and Buxton Heath and Horsford Rifle Range just to the north of Norwich. In a good season the density of butterflies can be substantial, particularly if you make your visit some two to three weeks after the butterflies first emerge; a visit towards the end of June would be good this year. Males emerge before the females, a not uncommon behaviour in butterflies and something that is known as protrandry.

While many of our familiar butterflies are wanderers, with some actually moving into Britain from the Continent, the blues tend to be rather sedentary in their habits and the Silver-studded Blue is no exception. Most individuals move less than fifty metres over their lifetime, instead remaining within a patch of suitable heathland where they can nectar on heather, cross-leaved heath, bramble and bird’s-foot trefoil. Like most blues, Silver-studded Blues are dependent upon the presence of particular ant species (most notably Lasius niger and Lasius alienus), in whose nests the butterfly’s larvae develop. This means that adult densities are closely correlated with those of ant nests; as such, the best place to search for the butterflies is in areas of recently disturbed ground where the ants benefit from the warm conditions associated with a short sward structure.

Volunteers from the Norfolk branch of Butterfly Conservation are leading two weekday trips to look for Silver-studded Blues over the coming weeks. The first is Tuesday 28th June on Buxton Heath at 10am and the other is on Wednesday 6th July on Kelling Heath at 2pm. All are welcome and full details can be found at

Monday, 20 June 2011

A croak in the bushes

I had never heard a Nightingale croak before! That such a renowned songster should utter an agitated amphibian croak came as a surprise. It was something quite unexpected, something that had passed me by all these years; an overlooked oddity that highlighted the gaps that remain in my experiences of our wildlife.

Oaken Wood is part of a much larger expanse of forest that spreads, lush and verdant, across the Surrey/Sussex borderlands. Owned by the Forestry Commission, Oaken Wood is managed as a reserve by Butterfly Conservation for its rich butterfly fauna, which includes such notable species as Purple Emperor, White Admiral and Wood White. It is also ideal for Nightingales, the thick regrowth providing the scrubby cover they favour for breeding.

According to Tony there were a dozen pairs or so here and, as we moved through the wood, snatches of male song echoed from the shadows. Restrained though they are, these short, measured flurries of song suggest that any moment the songster will break into an even louder and more resonant tune. Despite the association with thick cover, Tony noted that most of the nests would be within a couple of metres of the edge, something he had been taught as a boy by his father, an old boy ringer I’d met some years ago. Fewer than a dozen Nightingale nests are monitored each year (for the BTO Nest Record Scheme) but we hoped to add to that total through our visit to this site.

A soft hweet stopped us in our tracks – an off-nest female calling to her mate. Settling down just on the edge of the thicker cover and allowing our eyes to adjust to the gloom we watched and listened to see if we could follow her back to the nest. Tony took up a position further into the gloom, prompting the female to issue a frog-like croaking call. This meant that we were close to the nest and that it contained either eggs that were very close to hatching or chicks. Over the next hour, a patient game of watching ensued; every now and then I would glimpse the female, silhouetted against a patch of sunlight striking down through the gloom from a gap in the canopy. She was carrying food, so now it was certain that the nest contained chicks.

The patience paid off, the female returning again and again to the same patch of loose bramble cover, beneath which we found the surprisingly large nest, with its deep cup and five dark chicks. In the soft, droning gloom of the wood it seemed a very intimate moment and I felt privileged to have shared it with these wonderful croaking birds.