Saturday 23 June 2012

Lush growth shelters nesting birds


Even with such disappointing weather, the vegetation has become lush and luxuriant. Dense stands of nettles, punctuated with the taller branching stems of umbellifers, carpet much of the ground in the scruffy margins of damp fields and along the edges of woodland rides. I really notice the extent to which the vegetation has developed because of my regular visits to the same bits of habitat to check on nesting birds found earlier in the season. Nests that appeared rather exposed earlier in the year are now cloaked with verdant growth, something that can make them difficult to relocate if you do not take careful notes.

One particular patch of habitat, just to the side of a busy footpath, provides cover for a nesting whitethroat and also, I suspect, a chiffchaff. I found the former nest a couple of weeks ago, when movement through the patch was easy enough and I have a track by which I can return to the nest. I say ‘track’ but it is more like a series of stepping-stones, my movements carefully placed to avoid attracting unwanted interest to the nest. The chiffchaff has nested more recently and, while I have a good idea of where the nest is located, I will not make an approach for fear of damaging the nest woven into the vegetation.

The whitethroat nest is barely 20 centimetres off the ground, wedged into grass and dead umbellifer stems and beautifully hidden from predators. It would be all too easy to overlook. Over the years I have learnt that nettles and grasses can be parted with two sticks to leave little evidence of your visit and that bramble can be worked in a similar manner and that it quickly springs back into place. However, any piece of vegetation bound together with cleavers is best left untouched.

The whitethroat was incubating four eggs on my last visit and these are due to hatch any day now, my next visit timed to make a count of the number of youngsters that emerge and to provide a good indication of the date on which I should return to ring the young. The chicks grow with alarming speed and just a week after hatching they will be too large be to approached, the young likely to scatter from the nest as they would do if approached by a predator. I once witnessed the advantages of this strategy when attracted to a bramble by the harsh alarm calls of a whitethroat pair. Wrapped around a bramble stem, with its head in the empty nest, was a grass snake; the chicks were scattered elsewhere around the bush, out of danger but still able to attract a parent in with food.

Friday 22 June 2012

Moist mornings favour slugs


The forest trails are still damp with last night’s rain and scattered puddles reveal the extent of the downpour. Many are edged sap-green and yellow, evidence of the conifer pollen that has been making me sneeze of late. The damp ground is clearly to the liking of the slugs, various species of which can be seen crossing the normally dusty ground. Some are familiar to me, species that are found in many different habitats and which are well represented across the county, but others are unfamiliar and will, for the moment, remain so.

Each slug leaves behind it evidence of its passing in the form of a trail of slime. The slime, like that of snails, was once thought to have magical properties, even being used to treat coughs and sore throats. Interestingly, at least for snail slime, there is a scientific basis to such a use, since it has been discovered that the slime has antibacterial properties and is also effective in repairing skin blemishes. The use of slugs, boiled in milk, as a cure for consumption has rather less basis in scientific fact. The same can be said for the tradition of rubbing a slug on a wart and then impaling the unfortunate gastropod on a thorn. It was believed that as the slug died so the wart would disappear.

It is easy to see why slugs appear close to the top of any poll of garden pests. They will eat just about anything but have a preference for succulent new growth, often in the form of newly sprouted vegetable plants and salad leaves. They have, however, also been noted to feed on milk, carrion, damp newspaper and lichens! We have twenty-odd species in Britain but only a few can rightly be regarded as a nuisance in the garden. Others are restricted to particular habitats, for example mature woodland, or occur at low densities and are sensitive to human disturbance.

These woodland slugs, crossing the forest ride ahead of me, do fascinate me though. Some, like the glossy black examples as long as my little finger, are rather striking even if, without an external shell, they are less engaging than their snail counterparts. The small number of species suggests that this is a group that the amateur entomologist can quickly become familiar with and, additionally, many can be found in gardens with relative ease. All can be kept in captivity and, given the right conditions, will breed successfully, providing a good starting point for the young naturalist. Unlike snails, however, slugs are prone to desiccation and need to be kept damp. This is the reason that I tend to see more about in the forest on those damp mornings following overnight rain.

Thursday 21 June 2012

Extending our knowledge of a rare mouse


The other evening I received an email from a friend to which was attached a photograph of a dead mouse, brought in by their cat. There was nothing unusual in this except that the mouse had a broad yellow collar across the throat. The friend had noticed that this mouse was somewhat different from the wood mice that her two cats often delivered and she wondered if it might be a yellow-necked mouse. Although closely related to the wood mouse, the yellow-necked mouse is a slightly larger, more robust species, with a distribution restricted to the south of England and parts of Wales. The photograph certainly suggested that it might be a yellow-necked mouse so I asked that it be put in the freezer until I was back in the brecks and could take a look.

Further inspection revealed that it was indeed a yellow-necked mouse and one of only a handful of records of this species within the county. We are right on the edge of the range of this species but now have records from across the southern part of Norfolk, extending as far north as near Watton. One of the key features of this species is the broad yellow neck collar, which extends right across the throat to reach the darker dorsal fur on both sides of the neck. A mature male wood mouse can have a sizeable yellow throat patch, but this does not reach the darker dorsal fur to form a wide band.

One of the interesting things about this species is the contrast between the strongly southern distribution in England and the fact that it occurs further north in Scandinavia than the wood mouse. There is evidence that within England the species is most strongly associated with mature deciduous woodland, notably long-established or ancient woodland, and that it is absent from many of the more ‘open field’ habitats utilised by the adaptable wood mouse.

The hunting range of the cat which brought in this mouse almost certainly overlaps with a site where small mammal traps have been deployed on numerous occasions, without ever catching a yellow-necked mouse. It might be that the mice are present at a very low density – their home ranges are larger than those wood mice, so densities are lower – or that the very high densities of bank voles at the site excluded them from the traps. Either way, we do need to take another look with the traps to see if we can identify where these mice are and in what numbers. While cat predation remains a drain on small mammal populations, on this occasion it has identified the presence of a rare species in this part of the county.

Wednesday 20 June 2012

Downland


Once a backdrop to my youth, the vast chalk downlands of southern England still retain a strong hold on me and I think of them often. Steep slopes, rippled by thin soils that creep downhill under the pull of gravity, with domed summits and dipping valleys, their presence lingers deep within me, a comforting sense of something ancient and unchanging. It is of these slopes that I think when I hear the pomp of Elgar, delight in the lines of Edward Thomas or gaze on the works of Eric Ravilious. Such strong attachment underlines the spirit of place, a sense of one’s roots and the shaping influence of the landscape within which one grows up. Had I been born on the edge of the Yorkshire Moors or deep within the fens, it would have been a different landscape that would now exert its hold on me.

I am interested in the way that the southern downlands have become something of a symbol for lost Britain, the echoes of a golden age where our touch upon the land was somewhat lighter than it is today, where space remained for nature and where an outdoor childhood was the norm and not the exception. At such a remote distance there is a risk of shaping the past, rose-tinted, into something else, something that it is not. You only have to look at the nature writing of the time to discover writers who, like me, looked back fondly to a much earlier time, when our presence was less heavily borne by the land.

It would be fair to say that the downs have suffered fewer intrusions than many other parts of Britain. With slopes too steep for arable they have stocked those livestock able to make a living on the thin, relatively poor soils. True, they have provided the lime that fertilised those early crops and their lower slopes have been striped of timber, but their imposing nature has stifled urban sprawl and they remain sparsely populated. While many of the villages may have lost their sense of community, watered down by the commuter families unwilling to put down roots, others remain connected to the land and each other, maintaining the bond between landscape and its people.

This connection with the land is something that we need to see reinvigorated in the young. While we are an increasingly urbanised population, there is still an opportunity to get youngsters reconnected with the natural world around them and, perhaps more importantly, with a sense of their heritage and their origins. We need these urban communities to share this feeling of belonging, of having a connection with the landscape and an understanding of why this matters.


Tuesday 19 June 2012

From the edge of the reeds


It is a cool and overcast morning and not at all like summer. The water through which I am slowly working my way, a great expanse of flooded gravel pit, feels warmer than the air above and I am glad of the long-sleeved top and chest waders I am wearing. The long sleeves also offer protection against the biting insects that cloud the shallows, where small willows overhang and fringing reedbeds crowd and jostle. It is slow work, moving carefully through the reeds and looking for the reed warbler nests that are the core of our study. The bigger beds feel exotic, like a scene from an old movie set in the jungles of the Far East; who knows what will be revealed when I emerge from the dense growth.

Many of the reed stems show signs of other inhabitants ­– the haul-out site of choice for dragonfly and damselfly nymphs. It is the crisp and fragile exoskeletons from which the dragonflies have already emerged that I most often encounter but sometimes it is the dragonflies themselves, fresh and glistening with their newly expanded wings, resting before their first flight.

The reed warblers chart my progress, a bird rattling into song as I enter its territory and approach the nest. A quick check of the contents or, if it is a new nest, some measurements on its location and the addition of a grid reference from the GPS. Then I am off again, working each bed and each pit to build up a picture of this breeding population.

There are moments when I am still, perhaps taking notes or scanning for the origins of a particular call. It is at such times that I blend in and become part of the reedbed. The other inhabitants sometimes stumble across me; the toad that bumps into my waders, the lazy pike that glides in and takes up station in the shadow I cast. Then, today, it is an otter that approaches across the corner of the pit, unawares. I stand motionless, not daring to imagine that the otter will continue on a course that will see it reach a point just a few feet in front of me. The broad dark head, with even darker eyes, seems fixed on me but still it comes on. Then, barely an otter’s length distant, it unravels my outline from the vegetation and wheels away in a single, noisy movement. The great head vanishes below the surface and with a powerful motion of the tail it is gone, a trail of bubbles the only evidence of its departure. It is a magical moment, my first encounter with this most wonderful of creatures at this site.

Monday 18 June 2012

First view of a Jay's nest


The raucous calls of the jay are a familiar enough sound at this time of the year and the impression locally is that these birds are doing rather well. The pair breeding on the edge of some wet woodland at work has built its nest high on the ivy-covered trunk of a birch. This is a typical place for a nest and most of those that I have found in the past have been in similar positions: in cover, against the trunk and high off the ground. Naturally enough, this makes them inaccessible to the nest recorder seeking to monitor the nest contents for the BTO’s Nest Record Scheme (www.bto.org/nrs).

Fortunately, I had an opportunity the other weekend to take my first view inside a jay’s nest. I was helping to lead a course training new nest recorders on how to find, approach and monitor nests safely. The course was targeted at heathland and scrubby habitat species and was based in the Surrey Hills, a spectacular piece of habitat, especially now that the A3 has been re-routed through a tunnel to leave a vast expanse of grassy heath.

One of the students spotted the nest, which was placed just 18 feet above the ground in a large holly. The bird had come off on our approach and the nature of the holly offered a safe and easy climb to check the contents. From below the nest looked similar to those of many other corvids, with a foundation of sticks, but it was smaller and had a neater appearance. I was quickly up into the shrub and looking in at the nest contents – four pale eggs on a dark nest cup. The literature describes the nest as looking like that of a giant bullfinch, the cup neatly lined with dark rootlets and sitting on a foundation of larger sticks. Having seen many bullfinch nests I had been a little sceptical that the rather flimsy finch nest would be replicated in a more robust bird like a jay, but it was just as described. I was fascinated by the rootlets and by the fact that the birds had selected such delicate looking dark rootlets with which to line the nest.

Jay nest - Mike Toms
I took a quick reference photograph to show those on the ground and then came down. A few notes in the notebook, coupled with a grid reference and details of the four eggs, and we were off, leaving the female to return and to continue her two and a half weeks incubation. A colleague who lived locally would return in a couple of weeks to check on progress, following the nest through until the end, when, with luck, the chicks would fledge.