Monday, 31 March 2008

Not so mad March Hares

I can see them; hunkered down against the heavy rain are four brown hares, exposed to the elements in this everlasting Norfolk field. Their thick fur buffers them from the creeping cold of steady rain and shapes their hunched bodies, giving them the appearance of clods of earth left from when the field was last ploughed. Why should they be sitting like this, seemingly exposed both to the elements as well as to potential predators? I guess that while their thick fur affords protection against the elements, their keen eyes keep them alert to other dangers. Motionless, but ever watchful, they sit out the day.

Despite their size, hares often go unnoticed, even in an open landscape such as this. Much of the day is spent in a shallow scrape, known locally as either a ‘form’ or a ‘seat’. The hare will dig out the scrape, positioning her head at the narrow end, just above the level of the ground, her body and powerful hind legs tucked into the wider end of the form. Here she will remain, relying for protection on a combination of camouflage and, if flushed, speed. To have a hidden hare explode from underneath your feet can prove quite a shock, the hare leaping away from its form in one long fluid motion. Quickly up to speed it dashes away, the ears held erect unless the hare is moving at full speed, the tail horizontal and the powerful hind legs stretching out ahead of the forelegs to strike the ground with long strides. Satisfied that the danger is gone, the hare may then circle around in a wide arc to return to her original position in the form.

As winter relinquishes its hold to the coming spring, the brown hares undergo a spring moult, their new coat in place by the end of June. This time of the year also sees an apparent upsurge in breeding activity, though the females are actually fertile from the very start of the year through into August. The openness of the land, with crops not long emerged, opens a window on hare behaviour as it is acted out across our exposed arable landscape. In a few weeks time dominant males will guard fertile females, chasing away lower rank males if they come too close. The ‘boxing’ that is so strongly associated with this image of the mad March hare is not (normally) part of this male bravado but stems from a unreceptive female putting her suitor in his place. Such behaviour is a matter of weeks away. Perhaps, like me, the hares are waiting for spring proper to arrive and to lift their spirits from the deep melancholy imposed by such dreich weather.

Saturday, 8 March 2008

Sex in the shrubbery

The last few days have seen my very own soap opera being acted out in the garden. The heady mix of casual sex, illicit affairs and multiple partners has been performed by a small, and rather unobtrusive bird, known as the Dunnock. Rather drab in appearance, this familiar bird has an extraordinary social system. Both male and female Dunnocks have their own territories and, since those of the males are the larger in size, this may provide a male with access to more than one partner – a behaviour known as polygamy. Such behaviour is seen in a range of bird species.

Things begin to get interesting when two males share a territory. The dominant male (known as the alpha male) is really the territory holder but he is joined by a subordinate male (the beta male), who establishes himself through sheer persistence. The alpha male grudgingly accepts this interloper since it does offer something of advantage; when it comes to defending the territory two males are better than one. The downside is that the beta male also tries to secure matings with any females present within the territory. Interestingly, females deliberately solicit matings from the beta male, a behaviour that should help them when the chicks are born. If a male feels that he has fathered a brood of chicks then he is more likely to help provision them. By mating with multiple males, the female is actively trying to increase the number of males that will help rear her chicks – a decent breeding strategy when living in a habitat where food may not be that abundant.

Mind you, there is a competing factor here, in that each male wants to ensure that he makes the biggest contribution to the next generation. As such, the alpha male spends a lot of his time guarding his mate from other males. As a further safeguard the male indulges in some rather unusual courtship behaviour prior to mating. A male will approach his mate from behind; she will quiver her wings and raise her tail to indicate that she is receptive to his advances. The male will then peak at the female’s cloaca (effectively the external part of her reproductive system). This becomes enlarged and then exhibits strong pumping actions that eject some of the sperm from any previous matings. Satisfied that his own sperm will now make a greater contribution the male will mate with the female.

This complex system results from a series of competing factors; the need to secure help rearing the chicks, the need to defend access to a female and the urge to maximise your contribution to the next generation. Soap operas seem a little tame by comparison!

Friday, 7 March 2008


It is now just about light when I reach the forest, the day lengthening sufficiently to temper the shadows that push out from the thick stands of regimented conifers. The light, however, remains weak so early in the year and fails to lift the dull tones of the late winter landscape. The pale, silver-grey trunks of Beech, a small stand of which provides a thin veneer on the edge of the plantation, are stark reminders that spring proper is several weeks away. The ochres and russets of Bracken stands lay like sodden carpets, slowly rotting back into the ground; the few deciduous trees remain bare, starkly silhouetted against the sky and creating the illusion that this is a world of just two dimensions.

Under such conditions the land can seem very empty of life but it is there, just below the surface and steadying itself for the approaching spring. The most obvious signs of life are the birds, the noisy chattering of Siskins, large flocks of which can be found across the forest. While some of these birds will have bred locally, many more will have arrived from breeding grounds further north and east, mobile across the Continent in search of conifer seeds. Also in evidence are various mammals, most notably the Grey Squirrels which take to the trees as soon as they become aware of my arrival. The squirrels have, no doubt, been seeking out the food they buried back in the autumn, when there was plenty to eat and enough to store for the darker days ahead. Then there are the hunkered forms of Muntjac, heads down and feeding on the understorey vegetation. These too are alert to my presence and keep a respectful distance, ready to bound away, white tails erect.

On certain mornings, such as this, I am treated to a brief glimpse of the Red Deer which inhabit this part of the forest. They seem to be the most secretive of the deer, allowing only chance encounters and preferring to slip away unnoticed. Today I am lucky, they spot me at a distance and seem content to stand and watch my approach. Tall and erect, with an elegance of pose that suggests a degree of confidence, they remind me of a group of opera-goers, aloof and self-assured. This suggestion of tolerance is a front, for once I get a bit closer the confidence is lost and they turn quickly away, trotting off into a young plantation with nervous backward glances. That is the last that I will see of them today but it is good to know that they are still here, making the most of the forest at this quiet time of the year.

Thursday, 6 March 2008

The weather is all upside down

The weather of recent days has been all over the place, as if winter and spring are battling for control, each gaining the upper hand for a brief period before relinquishing their influence. Frustrating as this may be for us, it is more serious for our wildlife. Some birds have already started nesting attempts; a Collared Dove in town appears to be on eggs and our resident Blackbird has been busy collecting nesting material. Many others are in full song; Woodlarks and Yellowhammers on areas of clearfell proclaim ownership of breeding territories, while Song Thrushes, Blackbirds and Wrens provide the start of an urban dawn chorus that will grow in complexity over the coming weeks. Should winter tighten her grip then these nesting attempts will fail. Early emergence by butterflies and bumblebees, will deplete crucial energy reserves unless early season nectar can be found. It could prove to be a testing time for our wildlife.

It is not that winter is clinging on longer into the year, rather that spring is happening earlier. This, as we all know, is the result of global climate change, and is likely to be a pattern that we will see with increasing regularity over the coming years. A number of correspondents have commented upon the way in which the seasons are no longer so clearly demarcated. Instead, they increasingly blur into one another, with late season frosts, early spring-like days and winter storms arriving weeks early.

The degree to which all this might impact upon our wildlife is largely unknown. It is likely that different species will react in different ways (and with different response times) to changing weather patterns. Such are the complexities of the interactions between species that some species may slip out of synch with one another, something known as a phenological decouplement. A good example of this is a simple food chain, involving trees, the caterpillars that feed upon their leaves and the tits that feed on the caterpillars. Blue and Great Tits time their breeding attempts so that the peak demand of their chicks for food matches the peak abundance of caterpillars. However, should the trees come into leaf that much earlier, then the peak in caterpillar abundance may shift, the species in question able to react to the changing abundance of plant material. The tits would then need to bring their own breeding attempts forward to match the new peak in caterpillar abundance. While there is good evidence that tits are now breeding earlier, they may not be able to keep getting earlier or, indeed, match the speed of change in the timing of the caterpillar peak. This is something that researchers will need to watch very closely.

Wednesday, 5 March 2008

A sculpture of Starlings

Each evening I see them; from a distance they appear as a smudge on the horizon, moving too rapidly and in too many different dimensions to be smoke from one of the chimneys. Passing up through town towards home, I catch sight of them again. This time I am closer and the smudge dissipates to become a multitude of small black shapes, each one a Starling performing its part in this grand aerial ballet. On still evenings, as the sunlight begins to fade, to be replaced by the artificial glow of the streetlights, the Starlings gather in increasing numbers, coming together in tight flocks that wheel about the sky. Waves of brown shadow pulse across the flock as birds turn in harmony, flexing like muscle, each bird acting in unison to some unknown instruction. All the while the flock is increasing in size as small parties of Starlings come together, forming bigger groups that ultimately coalesce into a single fluid entity, numbering four thousand strong.

The presence of the Starlings has not gone unnoticed and the local Sparrowhawk can be seen most evenings, working the flock with characteristic poise. Selecting a suitable victim from the wheeling mass of black bodies will not be easy and more often than not the Sparrowhawk will fail to secure a meal. The performance lasts for an hour or more before, suddenly, as the last of the natural light slips away, the Starlings fall like a shower of arrows launched by a whole host of English bowmen. Such is the speed of their descent into the thick cover provided by a line of conifers that a loud rushing sound can be heard, again suggesting the flight of arrows falling upon ranks of infantry. As the remainder of the flock wheels in ever tightening arcs above the trees so more and more birds slip down into their night time roost.

Later in the evening, as I slip out for a pint of milk, I pass the conifers. There is a soft babble of noise, which reminds me of a concert audience just prior to the lifting of the curtain. The chatter has an edge of excitement to it and, if one were to anthropomorphise, you could just imagine the birds catching up on the day’s gossip before settling down for the night ahead. I wonder for how long this roost will be tolerated. The sheer numbers of birds involved means that the cars parked at this end of the street are splattered with droppings, as must be the garden within which the conifers sit. Other roosts in the town have been lost because of intolerance. Will this one suffer the same fate?

Tuesday, 4 March 2008

The Breckland Meres

I have always been fascinated by the Breckland meres, a series of 12 semi-permanent waterbodies quite unlike anything else in England. The meres are self-sustaining, their dramatically fluctuating water levels prevent the establishment of reedbed, swamp or, ultimately, woodland. With the exception of Mickle Mere, none of the meres have any visible inlet or outlet, the variations in water level resulting from the height of the water table within the surrounding chalk. When the water level is high, the meres may overflow, when it is low they may dry up completely. Along with Mickle Mere, the other prominent meres are Ringmere, Langmere, Fowlmere and the Devil’s Punchbowl – all to be found in a small area northeast of Thetford.

During their dry phases, the bare mud is soon colonised by some rather interesting plants, including the rare liverwort Riccia cavernosa. During the wet phase the meres support some rare invertebrates, characterised by their ability to survive long-periods of dry conditions either by burrowing down into the damp soil or surviving as a desiccated egg stage. In past centuries, locals would take advantage of the dry conditions by planting root crops in the rich soil revealed by retreating waters. On occasions the meres would remain dry for more than a year, but water levels could rise suddenly and locals might lose their crops or be forced to finish harvesting in knee-deep water.

These days, the water levels in the meres are maintained through a management plan that controls the level of the water table by halting extraction for agricultural uses if there is any threat to the meres. Of course, the meres must be allowed to drain every few years, otherwise the delicate balance needed to maintain the character of the meres and their unique biological identity would be lost.

The meres are also fascinating because of the history associated with them. Excavations at Mickle Mere and West Mere have revealed the presence of prehistoric lake dwellings, suggesting a long period of human use of the sites. Ringmere was the site of a fierce battle between Danish invaders and the Saxon ruler Ulfkytel. The Norse scald, Ottar, described the battle and noted how ‘from Hringmar field the chime of war’ was heard. The battle also appears in the Anglo Saxon Chronicle and it is noted that the Saxon force, camped by the mere, was beaten by the treachery of a servant who had Danish ancestry. So many of Norfolk’s great naturalist writers were drawn to the meres and commented upon the bleak open landscape within which they sat. While the landscape may have changed, the meres are an ever-present feature of great antiquity, and it is essential that we work to maintain them.

Monday, 3 March 2008

Scoping a Scaup

Thompson Water is sufficiently far off the beaten track to make for good birdwatching. Situated on the edge of the STANTA training area, at the end of a rough track, it is overlooked by many birdwatchers, drawing crowds only when something suitably rare turns up, such as the Pied-billed Grebe which appeared in 1999. This sizeable inland waterbody is part of a wider Norfolk Wildlife Trust reserve and is a good place to look for wintering wildfowl. Last weekend, for example, I counted 26 Tufted Duck, a Pochard, six Gadwall and, most significantly, a solitary Scaup.

The Scaup is a winter visitor to Norfolk, with most individuals wintering on the sea off the Wash and the North Norfolk coast. Here they frequent the shallows of the mussel beds where they dive for ragworms, crustaceans and mussels; the name ‘scaup’ is derived from an old Scottish word for mussel bed. Numbers vary between years, with somewhere between 40 and 200 birds present annually. Higher numbers occur during cold winters, when birds leave other wintering areas off the Danish, German and Dutch coasts. In times past, huge winter flocks were noted at other British sites, attracted by the rich feeding opportunities provided by the sewage outfalls of old-fashioned treatment works. As new technologies came on stream, leading to less waste reaching the sea, the feeding opportunities were lost and the flocks diminished in size. Since much of the feeding takes place at night, with the birds retreating further offshore during the day, watching wintering Scaup can be a frustrating business.

However, despite the tendency to winter off the coast they are quite tolerant of brackish or even fresh water and inland records have become more frequent over the last couple of decades, making viewing that much easier. As such, it is worth scanning flocks of wintering duck on inland waters to see if any Scaup are present. This clearly paid off at Thompson last weekend. Despite the superficial similarity between the Scaup and the female Tufted Ducks with which it was associating at Thompson, it stood out quite clearly; a bulkier bird, obviously larger than the ‘tufties’ and more similar in size to the male Pochard that was also present. The head also seemed bulky, evenly rounded at the back and lacking the tell-tale tuft of the aptly-named Tufted Duck. More obvious features were the large white facial blaze and the pale cheek patch. Interestingly, some female Tufted Ducks may show a white blaze but this is never as pronounced as that seen in Scaup. I spent twenty minutes or so watching the bird, making the most of the good light and easy viewing to get better acquainted with this uncommon visitor.