Saturday, 15 November 2008

A blustery day

I appreciate days like this; a bright clear blue sky which brings out the best of autumn’s tonal palette, coupled with a fresh wind that carries a hint of winter chill. It is the kind of weather that makes you feel alive, as each of your senses is stimulated in turn. Other creatures also seem to respond to the conditions. The local Jackdaws, for instance, have adopted an almost playful attitude. They rise up from the chimney pots on arched wings, allowing the breeze to pick them up and then fling them across the sky in a controlled glide; an arc of ragged black and sooty grey accompanied by soft cackling calls. This game continues for some time, pairs of birds seemingly enjoying themselves and immersing in an activity that appears to serve no other direct purpose. For an instant the game is interrupted, as the Jackdaws spot a Carrion Crow which has strayed too close to the patch of sky that the Jackdaws regard as their own. Working in unison they harass the crow, lunging at the bigger bird  from above and forcing it to twist and swerve in order to avoid being hit by outstretched claws or a stabbing beak. The crow responds by calling but the Jackdaws are soon successful in driving it away.

While some of the local trees have shed their leaves, others are retained and with the wind compose an overture of noise, like a succession of waves pulling back across the small pebbles of a beach. Many of the leaves retain some green, the process of drawing back nutrients not yet complete. It won’t be long until these leaves fall, perhaps prompted by another night time frost. There does not seem to be much fruit on many of the hedgerows, a few haws and hips but little in the way of tree seed. This suggests that it might be a difficult winter for some birds and I would expect to see greater use of garden feeding stations by species like Coal Tit, Chaffinch, Nuthatch and Woodpigeon.

Over recent weeks both squirrels and Jays have been working hard to store seed for the months ahead and, no doubt, some overlooked seeds will germinate in our flowerbeds come spring. Some may be unearthed earlier as bits of garden are reworked during this season when so much of the groundwork is done. This is another reason to relish the outdoors on such a day. Stand still too long and you will feel the cold but get stuck into some outdoor chores and you’ll keep yourself warm, ending the day with a healthy flush across your cheeks and deserving of a warm bath and a comfortable spot inside as darkness falls.

Friday, 14 November 2008

In praise of the pond hen

There are five Moorhens on the old pond at the moment, their stuttering swimming strokes tracing lines through the waterweed as they move in and out of shadow. It seems that just about any piece of water will suit them, from the extensive reedbeds of coastal marshes through to the sunken hollows of the larger grassy fields.

The Moorhen has long fascinated me, seemingly innocuous and predominantly sedentary, you might think that it has little of interest to offer the observer. Yet, nothing could be further from the truth. This is a bird of contrasts; a cooperative breeder (whose early brood young may stay on to help rear later broods) but which is not averse to dumping eggs in the nests of neighbouring pairs. While our populations are largely sedentary, those from further north are migratory in habits. Other aspects of the annual cycle are equally interesting.

The long breeding season begins early in the year, with the first eggs laid from the middle of March, and the season itself continues through into August. The first nests are often predated, perhaps because of the lack of nesting cover so early in the year. Undeterred, pairs will lay repeat clutches and many may rear two broods over the summer, with some managing to raise three. Then there are the nests themselves. Moorhens make three different types of nest. The first to be built are the display nests; these consist of sedges, reeds and dead twigs and are used for sexual display and, ultimately, coition. The first of these may be constructed from late February onwards, with some territories sporting up to five such platforms. Then there is the egg nest, built from fresh or dead water plants, usually on the ground within shallow water. The size of the nest may be enhanced if water levels rise. Very occasionally the nest may be built in a bush, possibly several metres above the ground and on top of the old nest of another species. Finally, there are the brood nests; constructed soon after the eggs hatch, these provide a refuge for the young chicks.

At this time of the year, however, the Moorhens are more concerned with finding sufficient food to get them through the winter. Many pairs will remain on their territories as long as they have access to open water. Should these ice over then the birds will be forced to move elsewhere, possibly onto neutral areas where they will feed alongside other birds. Even here, they are fun to watch and we are fortunate that our Moorhens are so trusting of Man. In other parts of their range, where they are a table bird, they tend to be shy and retiring.

Thursday, 13 November 2008

Red-flanked Bluetail draws a crowd

The North Norfolk coast remains a real draw for birdwatchers and tends to be busy most weekends throughout the year, something which can prove a frustration to the locals upon occasion. The residents of Weynor Gardens, for example, could be forgiven for subscribing to such a view the other weekend, when large numbers of birdwatchers arrived to see the Red-flanked Bluetail that spent several days at Muckleburgh Hill. This particular site has a good track record for hosting wayward migrants in autumn and is always worth a visit if the weather conditions look favourable during late September and October. Unfortunately, parking is an issue if something rare turns up and this particular weekend was no exception. I have never enjoyed the crowds that can gather at ‘twitches’ and would have avoided making a visit to Muckleburgh Hill were it not for having a kind and understanding friend who owns one of the houses that border Kelling Heath.

Although the road was lined by cars, the crowd watching the bird was surprisingly small, in part because the bird was mobile and folk were spread over a fair area. The bird itself, a very rare but increasing vagrant from the Russian Taiga, was working the available cover, dropping down periodically from the compact trees to feed on the ground or from low exposed branches. Slightly larger than a Robin, the bluetail was a very smart little bird. Similar in general structure to a Redstart, it showed the blue tail and orange flanks which give the bird its name. This was either a female or a first winter male and so had grey-brown upperparts and lacked the dirty blue plumage of an adult male. Even so, it oozed personality as it flitted down to feed before flying back into cover. As it moved between little patches of cover, so the back of the watching crowd suddenly had front row seats and, with a well-behaved crowd, the audience were treated to a delightful performance.

Curiously though, the bluetail was almost upstaged by the presence of a Spotted Flycatcher – an exceptionally late record and presumably a migrant from further east that had also been blown across the North Sea. The 2006 Bird & Mammal report gives a record late date of 26th September, so this bird was many weeks later than would normally be expected. The quality of Muckleburgh Hill was further emphasised by the presence of a Firecrest and at least one Chiffchaff. All of these birds were duly noted in my field notebook and, once home, were entered onto the BirdTrack system ( developed by the British Trust for Ornithology. This means that they will feed through into the Bird Atlas 2007-11 and reach the County Bird Recorder.

Wednesday, 12 November 2008

Adversity can promote a long life

I was raised within the sylvan embrace of the Low Weald; a well-wooded strip of country that rests on an ancient geology, now exposed with the eroding away of its covering chalk dome. To grow up among trees has left its mark on me and I always feel more comfortable in their presence. Yet, as I have mentioned before, trees have become an almost unseen backdrop to our lives. Their size and longevity, coupled with the fact that they remain rooted to one spot, seemingly makes them inconspicuous to casual observers. This also means that we tend to treat them badly, using them as architectural features – hemmed in by roads and pavements, or cutting them back indiscriminately because they block our view or shed leaves where we do not want them.

It is also fair to say that we do not, by and large, understand trees or fully comprehend our impact upon their lives. We have this conception that trees mature, become full of decay and, by doing so, reach the end of their lives. However, decay is part of the normal development of a tree and many trees will undergo retrenchment, reducing the area over which new wood has to be laid down by shedding branches and twigs, before going on for many more decades. While trees lack both an immune system and a wound repair system, they can wall off and bypass damaged tissue, effectively allowing them to redirect growth in a new direction and to balance this against incoming resources.  This whole idea that trees have a defined lifespan and die of old age is something of a myth, for most trees are felled before they even reach middle age.

How long a particular tree has left to live, our intervention excluded, has little to do with how old it is but far more to do with its size and rate of growth. The truly veteran trees of Europe are not the oaks of landscaped parkland with their spread of great branches; instead they are the small twisted forms of cypresses, growing slowly on the high slopes of Cretan mountains. For those trees that have in some way been managed by Man, it is those that have been pollarded which tend towards longer life. In both cases, it is adversity which has prolonged life, by slowing the rate of growth. Since so much of a tree’s fortune will depend upon our influence, it is we who determine how they live and when they will die. Oliver Rackham, the great woodland ecologist, summed this up just perfectly when he said that when it comes to life expectancy in trees the ‘battlefield’ is a better analogy than the ‘almshouse’.

Tuesday, 11 November 2008

Some chirpy birds

At least one small group of Crossbills has been active around Croxton Heath over recent days, their chirpy calls expressed like a group of overexcited children on their first independent outing. I seem to catch up with them most mornings and they provide a new backdrop to my early morning walks. Their loud, metallic-sounding calls are a welcome addition to a soundscape that is much diminished with the approach of winter (the wistful Robin and ever present Wren my usual companions).

The presence of these robust little birds owes everything to the dark plantations of pine and, in particular, spruce, upon whose seeds the birds depend. The changing fortunes of the Crossbill within Norfolk owe much to the establishment and subsequent maturing of these conifers, an increase in feeding opportunities and nesting habitat. The primary source of these birds, however, is the great tract of boreal forest that stretches across Scandinavia and east towards the Pacific. This great forest supports the Crossbill populations from which our far smaller population is derived and, in many years, supplemented.

Crossbill populations are so dependent upon the conifer seeds that they will quickly vacate large areas within which seed supplies have been exhausted. This results in large-scale irruptive movements, the birds tending to move in early summer once they have finished breeding. Breeding itself normally takes place incredibly early in the year, during late winter to be precise, and there are even old Norfolk records of incubating females seen with fresh snowfall around them. Such early breeding means that some pairs will be egg-laying in the latter half of December. The irruptive nature of Scandinavia populations brings new arrivals into Norfolk in numbers that can vary dramatically from one year to the next. These birds can turn up in unusual situations – we once caught one in a reedbed – but ultimately they supplement our key breeding populations in Thetford Forest, in the woods around Sandringham and along the Holt to Cromer ridge. Breeding was first documented within Breckland in 1815, when a nest was taken at Livermere, and is certainly considered an annual occurrence now.  As well as winter breeding records, there are occasional records of birds breeding in late summer, some of which may include youngsters breeding in the same year in which they were born.

The future of our breeding Crossbills is dependent upon a number of different factors, including the form and age of our conifer plantations. Many of those within Breckland are currently at an ideal age  but these will soon be felled and this will diminish the resources available to these delightful little birds. If we want to keep them then we need a good mix of trees of differing age.

Monday, 10 November 2008

A touch of gold

Norfolk is well known for its great expanse of farmland; the huge fields are dominated by arable monocultures and there are few hedgerows or woodlots to halt the eye as you across the horizon. On dull winter days such fields can seem rather bleak; the dull shades of landscape merging into those of overcast skies, but with a frosty morning the earthen colours are warmed and lifted by the brightness of a clear blue sky. It is on such days that I like to search the fields for wintering waders and wildfowl. Towards the coast, fields may be crowded with feeding geese, pink-feet and brents, while inland they are dominated by waders like Lapwing and Golden Plover.

The Golden Plovers are a winter treat; birds from the upland breeding populations of northern England and Scotland are joined by those from Norway, Iceland, the Faeroes and even the westernmost parts of Siberia. Invariably, they can be found feeding alongside the noticeably larger Lapwings. It has been shown that the Golden Plovers actually use the presence of their larger cousins to indicate rich feeding opportunities. An arriving flock of ‘goldies’ (as us birdwatchers often call them) will drop down and land amongst the Lapwing, individual birds then adjusting their position within the flock on the basis of how well other birds seem to be feeding.

Nationally, our wintering Golden Plovers prefer to feed on earthworm-rich pastures but in Norfolk such pastures are uncommon and the birds associate with sugar beet, winter cereal and newly-planted oil seed rape. Flocks will use different areas for roosting and feeding but many seem to return to traditional sites from one winter to the next, making it relatively easy to track them down. However, birds will move in response to hard weather. If it is cold on the Continent then more arrive here; if it is cold here then the birds move off elsewhere. Much of the activity actually takes place at night. Simon Gillings, one of my colleagues at the British Trust for Ornithology, has spent a number of years studying the birds and their nocturnal feeding habits. He found that up to 80% of birds feed at night, often on fields some distance from where they had spent the day.

The flocks are worth scanning for other reasons, not least because the ‘goldies’ and Lapwings are sometimes joined by other birds. Just recently, near East Harling, one particular flock of plovers also held an American Golden Plover and a Dotterel ­– two really good birds for this part of the country. Black-headed Gulls are quite often found with the flocks, attracted by the easy pickings they can obtain by robbing the plovers of newly extracted earthworms.