Monday, 30 April 2007

Ring Ouzels on passage

The last two weeks have seen very good numbers of ring ouzels at various sites along the North Norfolk coast. These birds, members of the thrush family, winter around the Mediterranean Basin and breed in upland areas across Britain and other parts of Europe. Given their preference for breeding sites situated on scree and boulder-strewn slopes, some 250m above sea level, it is hardly surprising that your only chances to see them within Norfolk come during their spring and autumn migrations. With their smoky black plumage, ring ouzels are superficially similar in appearance to a blackbird and, being of comparable size, there is the possibility of confusion between the two. However, adult male ring ouzels sport a large white crescent on their breast and have wing feathers edged with a greyish white. The crescent is absent in young birds, and less prominent in most females, but the feather edging should be sufficiently apparent to allow an accurate identification. To my eye, ring ouzels adopt a more upright posture, reminiscent of a fieldfare, than that seen in a blackbird.

Over the past two weeks we have seen a peak in the numbers of ring ouzels within the county, with small groups of birds dotted along the coast from Heacham and Holme to Winterton and beyond. These birds are likely to be en route to breeding grounds within Scandinavia; the British breeders having passed through the country several weeks earlier and arriving from a different direction. For these Scandinavian birds, the spring passage appears to be something of a leisurely affair, with individuals frequenting the same coastal scrub and dunes over several days. This provides them with an opportunity to feed and rest before migrating onwards to their final destination. In some years, males that have chosen to stopover here may indulge in a spot of singing, adding an unfamiliar song to the growing chorus of migrant songsters. The numbers of birds arriving during spring passage tend to be greater than seen during autumn and, in contrast to the pattern seen in autumn, there are also occasional records from well inland. Just last week, two were reported to me from near Diss. Although this pattern for inland records appears to have increased since the early 1990s, coastal sites are still favoured.

Like a number of other migrants, the ring ouzel population has been in decline and we have a seen a significant reduction in the size of the breeding range within Britain over recent decades. Although some of the causes of this decline may lay overseas, on the wintering grounds or migration routes, it is worth noting that acidification of breeding areas here may have reduced food availability and impacted upon breeding success.

Saturday, 7 April 2007

Fiery-eyed imp drops by

The lake at Livermere, which lies north of Bury St Edmunds and just over the border into Suffolk, has a reputation for attracting some of our less common birds during the spring migration. This may be a consequence of it being the only really large water body in the area. The lake itself sits within a surprisingly open landscape and it is possible to view most of the lake and its margins from just one or two points. A number of colleagues from work make regular visits during their lunch breaks and from time to time turn up something unusual. Just last week a black-necked grebe was found and this prompted me to make an evening visit to see this delightful bird.

In size, the black-necked grebe is intermediate between the dabchick or little grebe and the familiar great-crested grebe. It has a rounded, almost dumpy, body, with what can only be described as a powder-puff rear end. This powder-puff, which extends from the flanks towards the rear, is off-white or dirty grey in winter but during the summer it is replaced by a deep russet-brown. The rest of the body is black, except for a drooping fan of yellow feathers that extend from behind the fiery red eye and the whole effect suggests an impish character. The pointed bill appears to turn upwards at the tip, but this is an illusion, created by an abrupt narrowing of the lower mandible. Such a distinctive bird was easy to pick out from the various ducks, geese and gulls and I was soon able to watch it diving for food. I was struck by the buoyancy of the grebe. It sat very high on the water, almost as if it were a ball of cork, yet it was able to dive readily.

The black-necked grebe has a very interesting history in this country. Although it has a huge global distribution, Britain sits at the northernmost edge of its wintering range and has only a small breeding population. Although it is generally accepted that the species was first recorded breeding here in 1904, there is an intriguing piece of text from a manuscript written in 1771 by Pennant. This describes what seems likely to have been black-necked grebes breeding in the fens near Spalding. However, Pennant died in 1798 – some 60 years before the black-necked grebe was officially recognised as being a different species to the superficially similar slavonian grebe – and we cannot be certain of his identification. A few dozen pairs now breed annually in Britain, although those visiting East Anglia do so either in winter or on passage between wintering and breeding grounds. 

Friday, 6 April 2007

What price a love of the countryside

I know that I am far from being alone in my love of the countryside; like me, many others delight in the complexity and beauty of the natural world. There is so much to take in, as a myriad of animals and plants go about their daily lives. A recent letter, from EDP reader June Clarke, brought this home to me just the other day. The letter described some of the scenes witnessed on June’s walks down quiet country roads and there, bubbling to the surface of her prose, was an effervescent passion for the world about her. Like me, she is in awe of what she sees, hears, smells, tastes and touches.

It is very difficult to put a value on the enjoyment that we take from nature and, perhaps, it is wrong to even suggest that a value can be attributed to such bounty, so freely given. From a personal perspective, I find it very sad that some people do try to put a price on our wildlife and the environment within which it lives. The harsh realities of modern day economics may be the currency of our planners and policy makers but should they be allowed to price the countryside and its wildlife? Look at the figures quoted for land in this part of England – the same area of countryside may fetch twenty-times its value for residential use as it does for farmland. Yet, which provides the greater benefit for wildlife; high-density housing or mixed farming? I think you know the answer. To me, this illustrates the point that attempts to value the countryside are flawed, heavily biased by our blinkered view of the world as being there just for us. We are one species of many, all dependent and inter-dependent on the other forms of life that live alongside us. Should we, therefore, be allowed to claim it as our own?

While some may be willing to ask “what price an acre of wildflower meadow?”, it strikes me that we should resist such efforts, arguing that such things are, in reality, priceless. The countryside has an intrinsic and, in my mind, immeasurable value; a value that reflects its worth to the whole community of life that lives within it. Perhaps it is our inbuilt arrogance as a species, that means we so often look at the world around us purely from our own selfish perspective.

They say that you do not realise how much you truly value something until it is taken away from you. Well, go out into the countryside this weekend, stand there and take it all in; then ask yourself “How much will I miss this when it is gone?”

Thursday, 5 April 2007

Roe much in evidence

Two roe deer have been much in evidence over the last week or so, often glimpsed out in the open on a piece of newly established plantation forestry. The two roe, a male and a female (known as a buck and a doe), are alert to the presence of my dogs and rarely tolerate our approach. Once we are within 150 metres they are off into the forest. With an upright stance, black nose and moustachial stripe, there is something distinctly regimental about these animals. When disturbed they display a characteristic bounding gait, their white rumps signally that we have been seen and that the deer are confident in their ability to escape any potential pursuit. The rumps of both sexes are creamy-white at this time of the year and are shaped like an upside-down heart. The buck has a pair of small antlers; these are shed between late August and early January, and rarely exceed 30cm in height. Although females do not normally have antlers, there are a few documented records of females with small antlers.

The bucks are territorial at this time of the year, occupying ranges that tend to remain consistent in extent from year to year – even when one buck is replaced by a younger rival. Each male will attempt to defend the territory, and the two or three does it is likely to contain, for several seasons; although it is very unusual for one to hold onto a territory for more than three years. Females are less territorial and their ranges will often overlap with those of other does. The female will have mated back in July or August of last year but, unusually for a deer, she will have delayed implantation of her embryo until late December or early January – the young being born towards the end of May. Twins are common but in good habitats triplets may be produced.

I sometimes hear debates about the origins of our roe, with some observers referring to them as introduced, not indigenous to our countryside. In fact the roe is a native species. It did become extinct throughout much of Britain during historical times and by the beginning of the Eighteenth Century it was thought to be largely restricted to remnant woodlands within the Scottish Highlands. A range expansion followed but this only really took the population back as far south as the Scottish Borders. All of the southern populations are therefore thought to originate from reintroductions from continental Europe. While some are thought to be of Austrian origin, those in East Anglia derive from German stock, being reintroduced in 1884. Whatever their provenance it is certainly good to see these deer in our woodlands. 

Wednesday, 4 April 2007

Our smallest owl

The bird hide at Flitcham Abbey Farm is a hidden treasure, overlooking, as it does, a grazing marsh, complete with pond and areas of more open ground. The range of habitats attracts an impressive array of species and provides some excellent bird (and mammal) watching. The site is perhaps best known for its breeding little owls and this is why I made a special visit over the weekend. Although it is a site that I sometimes stop at on my way back from the North Norfolk coast, on Sunday I chose to make an early morning call instead. Morning is not the best time to visit because the hide faces east and the late winter sun can be a problem. However, I did have the hide to myself and there was plenty to see.

Two family parties of Egyptian geese were noisily seeing off any birds that came too close, their cream and brown youngsters oblivious to the hollerings of their over-protective parents. A dozen or so late redwings intermingled with grazing rabbits and thrushes, while a curlew went quietly about its business along the edge of the wetter ground. There was no sign of the kingfisher which nests in the exposed bank at the back of the pond, nor the tree sparrows that sometimes appear. There was also no sign of the little owls, at least from where I was sitting. These usually frequent a large tree in front of the hide but it was only the jackdaws that were active, busily cramming sticks into the available cavities. I decided to change position and left the hide to move further along the road so that I could look back towards the tree, with the sun behind me. This proved to be an excellent decision, for no sooner had I raised my binoculars to the tree than I spotted a squat shape sitting within the roots of the fallen trunk. This was a little owl, sat with piercing yellow eyes half closed but ever alert.

Little owls are fascinating birds, full of character and with an attitude that belies their tiny stature. First introduced into England during the mid-1800s, they really became established following introductions near Edenbridge in Kent and Oundle in Northamptonshire during the 1880s. Today, although widely distributed, they have declined somewhat, especially here within eastern England. The loss of suitable hunting and nesting opportunities may be to blame, so it is fortunate that Flitcham Abbey Farm has both in abundance. Flitcham is just east of King’s Lynn, off the A148, so do pop in and take a look. Make sure that you leave a donation in the box to support and acknowledge the efforts of the landowner.

Tuesday, 3 April 2007

Bumblebees herald spring

The sight and sound of queen bumblebees is a sure sign of spring. Newly emerged from winter hibernation, these large and fascinating insects will soon be searching for a suitable site in which to establish a nest. With their internal fat stores almost completely exhausted, the first priority is to seek out sources of early season nectar and pollen. Although the buff-tailed bumblebee may be seen visiting the catkins of sallow or garden flowers as early as February, the other common species may not be on the wing quite so early. It is a precarious time; early emergence may use up valuable resources if there is insufficient nectar and pollen to be found. If the weather turns cold, as it did towards the end of March, then the bees will seek shelter and become torpid, re-emerging once the weather improves. By the beginning of April all the common species will be on the wing, engaged in finding food. Interspersed with these bouts of foraging are periods spent sunbathing on exposed leaves, walls or stones, a behaviour that is thought to help with the development of the ovaries in readiness for egg laying.

There is then a change in bumblebee behaviour, with the introduction of low, contour-hugging flights, as individuals prospect for a suitable nest site. Preferred nest sites vary with species; while some bumblebees nest underground others may use old bird nests, nest boxes or tree cavities. The underground nests tend to be in the abandoned burrows made by small mammals, like mice and voles. These can be a scarce resource and competition for nests may be fierce. It is sometimes possible to find several dead queen bumblebees around the entrance of a small mammal nest being used by a seemingly victorious queen. One species, the red-tailed bumblebee, uses holes in bare ground, or adjacent to stones or concrete, which act as heat stores and aid the regulation of temperature within the nest.

The whole process of nest site location and selection may take several weeks but, once established, the queen soon gets on with the business of producing her first batch of eggs. Typically, the queen will line the nest with fine material, before constructing a brood chamber. This chamber is made of wax, extruded from her abdomen. It is into this that she will lay a batch of eggs, usually between eight and twelve in number; the queen having mated back in the autumn before going into hibernation. Alongside the brood chamber the queen will also construct a nectar store. This initial batch of eggs will become the first infertile workers that will tend subsequent broods but the queen will need to tend this first brood herself.

Monday, 2 April 2007

A nest of hair and lichen

There has been something of a totemic presence following my excursions of late. It seems that wherever I go I encounter long-tailed tits; their soft, bubbling contact calls alerting me to their presence.  I have stumbled across them in unexpected places, to the extent that one pair have even been busy building a nest just 20 metres from my office. Perhaps I should not be so surprised; long-tailed tits have been doing rather well of late, their breeding population buoyant after a run of mild winters. As is the case with other similarly diminutive and largely insectivorous birds, long-tailed tit populations can crash following a sudden winter cold snap. The winter of 1962/63, for example, is estimated to have reduced the breeding population to less than 20% of what it had been the previous autumn. No wonder that these tiny birds huddle together in communal roosts during the winter months and forage together in extended family parties, some eight to 20 individuals strong. These foraging groups aggressively defend communal home ranges throughout the winter, but from February onwards they disband to begin nesting.

Long-tailed tit nests are truly amazing, each one an oval-shaped dome made from moss, hair, wool and spider’s webs all carefully woven together within a suitable bush. Of the two nests local to me this spring, one is in gorse (prickly bushes are favoured because they provide additional protection from nest predators) and the other is in a Ceanothus. I am fortunate in having been able to watch the protracted construction of the latter nest over the last two weeks. Such is the complexity of the nest that it can take three weeks to build. As the dome is woven, the tits camouflage it with tiny flakes of lichen. The pair will often add 4,000 or more flakes before turning their attentions to lining the nest. For this, the birds must find as many as 2,000 feathers and it is only once the lining is complete that the birds can get down to the business of laying eggs. Laying can start as early as the first week of March in the south of England but here, in Breckland, it will always be a little later. Interestingly, research has revealed a trend towards earlier laying – a pattern that is most likely linked to global climate change.

Even with the camouflage and choice of nest location, nest losses to predators like jays and crows are high. Pairs that lose their nests in this way will often become helpers at the nests of close relatives, a behaviour that is clearly beneficial because nests with helpers are more productive. Again, this highlights the value of living in an extended family group.