Saturday, 13 November 2010

Nervous plovers give a stunning show


The Golden Plover flock is anything but settled and it seems likely that they have been harassed by a Peregrine or other raptor during recent days. Several hundred of these beautiful waders shuffle nervously on the exposed mud of one of the lagoons at Norfolk Wildlife Trust’s Cley reserve. A multitude of gleaming black eyes alert to danger, it only needs one bird to take to the wing and the rest of the flock erupts with a clearly discernable rush of wings. The flock rises sharply, forming a coherent mass and taking on a life of its own, pulsing and twisting in the air, flicking from gold upperwings to a flash of white underparts. It is easy to see how a would-be predator might find it difficult to single out a victim. Moments later, the flock having circled, and birds begin to drop back down to the deck. Each time the flock goes up there are groans from the other end of the hide. A juvenile American Golden Plover was keeping company with this flock yesterday and some birdwatchers are keen to pick it out from its mass of slightly larger, warmer coloured European relatives.

When you see the spectacle of a decent flock of waders on the wing, jinking and twisting through the air, it is easy to see their appeal. While some waders can be considered beautiful in their own right, the sight of many hundreds or thousands of individuals collected into a flock is truly amazing. They are not the only flock present today, with several hundred sleeping Teal, many dozen Wigeon and a sizeable number of Black-headed Gulls, but they are the only spectacle. Every now and then the panic of the plovers triggers the gulls to take flight. But with the gulls there is no synchrony, no sense of individuals working together in unison. Instead, the gulls merely give a ragged show – a random flurry of white, lacking direction and purpose.

Flocking provides a number of benefits, including those related to predation risk. If you are part of a flock then your chances of being the target of a predator are reduced. Having others of your kind with you when feeding means that while you have your head down searching for food, another individual will almost certainly have its head up scanning for predators. Golden Plover often flock with other birds, especially when they are feeding, and they can often be seen in the company of Lapwing or Black-headed Gulls. While the smaller plovers may lose the odd piece of food to a larger gull, again there are the benefits of having more eyes to watch out for predators. And the benefit for us? A spectacular show.

Friday, 12 November 2010

Bearded Tits much in evidence


Despite its name the Bearded Tit is not related to the familiar Blue and Great Tits that we see in our gardens. In fact, it is not entirely clear where it should be placed in terms of avian relatives. Previous studies had suggested that it should be regarded as a parrotbill but more recent work implies that its affinities are more closely linked to the larks. Of course, this matters little to the bird itself, nor to most birdwatchers. It shows a number of similarities to the tits in terms of appearance and it is certainly equally appealing. Interestingly, the latest revision to the English names ascribed to our birds has seen a reversion to a rather charming old name for the bird, namely Bearded Reedling. The male sports a rather handsome black ‘moustache’ and the species is associated with reedbeds so this could catch on. Certainly, it is a less contentious suggestion than some of those put forward for other birds – like Red-throated Loon (Red-throated Diver) and Mew Gull (Common Gull).

Two Bearded Reedlings have been seen on the local reserve over recent weeks, a rather welcome addition to a site on which they have never bred. Their appearance comes at a time of the year when, following a successful breeding season, many individuals undertake significant dispersive movements. Such movements are one reason why the species has been able to recover from a period when it looked as if it would be lost from Britain as a breeding species. During the winter of 1947, following loss of suitable breeding habitat, widespread persecution from egg collectors and a run of cold winters, there were thought to be fewer than five breeding pairs in the country – a single bird in Norfolk and 3-4 pairs at Minsmere.

Cold winters still have a big impact on the population but the combination of strong powers of dispersal and high levels of productivity help them bounce back rapidly. Not only do Bearded Reedlings compress their breeding attempts into an unusually short period, they often overlap successive attempts, enabling them to produce good numbers of chicks. The chicks leave the nest before they can fly and become independent at just 20-25 days of age.

With good numbers of these birds moving around the countryside, now is a good time to catch up with them. Sites with large reedbeds, such as in the Broads or along the North Norfolk coast, are well worth a visit. Although the cinnamon-brown colouration can make them difficult to spot they can be surprisingly approachable. Their characteristic pinging contact call often reveals their presence, as pairs or small parties work their way through a reedbed in search of food.

Thursday, 11 November 2010

Celebrating the bird observatories


Just over a decade ago I was fortunate enough to spend a few days on Heligoland, a North Sea island off the coast of Germany. It is a bizarre place, with a series of tax-free shops around the small harbour to serve day-tripping German tourists, a conference centre and various houses and apartments. The rest of the island is a mixture of rough ground, old fortifications and dunes. Importantly, however, it is the place where Heinrich G├Ątke spent 50 years studying the migration of birds and where he established his ‘vogelwarte’ or bird observatory. The observatory, a small building and well-vegetated ‘garden’, sits just below the ridge of the island and pulls in many migrant birds. Heligoland’s position in the North Sea means that it attracts vast numbers of migrant birds, allowing researchers and bird ringers to study bird movements in great detail.

The notion of the bird observatory arrived in Britain in the early 1930s, with the establishment of Skokholm Bird Observatory by the ornithologist and author Ronald Lockley. This small island observatory, located off the southwest coast of Wales, attracted the interest of leading ornithologists and it was not long before other observatories were opened at suitable sites elsewhere around the British and Irish coasts. Soon after the war the BTO set up a committee to coordinate the research efforts of the observatories, helping to standardise recording methods and to pool the new information that was being collated. The results from these early years appeared in a new journal, named Bird Migration, which makes fascinating reading and is something I dip into from time-to-time. The collective reports summarise each autumn and spring migration, charting arrivals and departures for a wide range of species.

Even though interest in the observatories waned a little during the 1960s, with interest turning towards what radar studies were revealing about bird migration, there has been a real resurgence of late as observatories attract a wider audience of birdwatchers and naturalists, keen on learning and experiencing migration in its many forms. Today, 18 observatories form the Bird Observatories Council, with Holme in Norfolk and Landguard in Suffolk our nearest ones. There are others that operate outside of this network, generating more information on bird movements.

The ability to catch and ring migrating birds in a systematic way provides an opportunity to look at how migration patterns may have changed and the extent to which such changes may reflect wider changes in bird populations. Many of the observatories also operate moth traps and collect information on the other wildlife on their sites. All act as a focus for local, regional or even national interest in wildlife and it is wonderful to see them doing so well.

Wednesday, 10 November 2010

Riverine


Having spent much of the day in the house, the weather outside a succession of heavy showers, I feel a need to go out and get some air. It’s late afternoon and a suggestion that the sun might be breaking through gives me the impetus that I need and I head down to the river. The walk is brisk, easing the stiffness from my joints and clearing the day’s paperwork from my mind, and I cut through the still dripping wood and strike out towards the meadow.

I like this bit of the river. It is off the beaten track and you have to pick your way through rank vegetation to rediscover its meandering course. The scattered Alders chart the river’s route through the meadow and I am soon settled on the bank, screened on three sides by nettles and rough grasses. Because movement through this bit of meadow is difficult and noisy, it is impossible to approach any animals or birds without scaring them away. I find that the best approach (as it is in many habitats) is to find a suitable spot in which to settle and to wait patiently for the wildlife to approach you.

I have not long been settled when the sun fades behind a thickening blanket of cloud, heralding the approach of another squally shower. At first the smooth surface of the river reveals just a few spots of rain but then, increasingly, the ripples coalesce as the rain’s intensity increases. With several layers of clothing, including a goose-down jacket and a waterproof, I will be dry enough but I hunch forward, drawing my legs up to protect my camera bag. From under my hood I still have a good view and watch the approach of a male Muntjac. He has not seen me, or if he has, he has mistaken me for a large grey mass, perhaps a rock or unmoving pile of decomposing vegetation. It is wonderful to be able to watch unseen, the deer browsing intermittently as it passes by just a few feet from me.

The rain strengthens further, becoming a rush of hail, noisy on my hood and reducing the visibility such that I lose sight of the Muntjac. Just as quickly as it arrived so the hail halts and, soon after, the rain too. A Grey Heron drifts in on broad wings; legs held below it drops to the opposite bank. It seems unsure but I cannot tell if it is my presence or the fact that there is no obvious route for it to take into the water, such is the growth of emergent bankside vegetation. The heron lifts itself away with strong strokes and the river is mine alone.

Tuesday, 9 November 2010

Hail the Woodcock pilot!


For two weekends on the trot I have been on the coast at first light to watch the arrival of migrating birds, picking out my first Bramblings and Fieldfares of the winter from many other newly arrived individuals. A persistent theme of both weekends has been the numbers of Goldcrests, arriving exhausted from their recent sea crossing and keen to feed up on small invertebrates gleaned from trees and shrubs.

Goldcrest, by Mike Toms

I am in awe of these tiny creatures. Weighing no more than 7g, they are one of the lightest birds to undertake regular sea crossings when on migration. This feat can be considered all the more remarkable by the fact that they carry little in the way of fat reserves and, with little fuel with which to make the journey, it is little wonder that they arrive exhausted. Equally remarkable, to my mind at least, is that these diminutive birds are able to survive long winter nights and low temperatures by burning up energy reserves that may see them lose a fifth of their body weight over a single night.

Our Goldcrests, those that I encounter in the forest throughout the summer months, are largely sedentary in habits. With the possible exception of those from more northerly parts of Britain, these individuals spend the winter here, with some moving into gardens to take advantage of the fat products that many householders now provide. Those from elsewhere in northern Europe, notably northern Scandinavia and Russia, move south or southwest in autumn and it is these birds that have been arriving along the Norfolk coast over the last few weeks.

Many are young birds, perhaps reflecting a good breeding season, but maybe also underlining their short lifespan and the high degree of turnover of individuals within the Goldcrest population. We handled a good number at one of our coastal ringing sites the other day and it was clear that some had just arrived, being of low weight and low fat score (we can score the amount of fat on a bird because the fat is carried in a pit on the chest and along the belly), while others had been in for a couple of days and had already fattened up.

The arrival of Goldcrests is now just about over, as is the case for many of our other winter visitors and passage migrants. The arrival of Goldcrests is often linked to the arrival of Woodcock and Short-eared Owls, something that might explain the folk name of ‘Woodcock pilot’ given to the Goldcrest. Among wildfowlers it is sometimes said that the Goldcrest hitches a ride in the plumage of migrating Woodcock, but it is similarity in the timing of their autumn movements that really underpins the association.

A torrent of otters

It has been nearly five hours of patient waiting, stood on the bridge, watching the river and listening for the telltale calls that would give away the otters’ presence. I’d seen them here earlier in the week, not well, but this weekend was my opportunity to get what I hoped would be a proper view.

Over the past 15 years I have had just three encounters with otters on this particular stretch of the river, so a series of reports of a family party was a clear draw. Patient watching, three hours before dusk last night and two from first light this morning, affords solitude, your senses alert to the wildlife around you but your mind clear to wander where it may. I’ve seen and heard many other creatures but not the otters, not yet at least.

Then a noise upriver suggests they are coming – squeaking calls and splashing sounds – and I feel myself tense with anticipation. They come at a rush, a torrent of otters moving quickly through the water close to the far bank. It is purposeful, with a mother otter leading four cubs under the bridge and out of sight. This is not the encounter I’d envisaged, one with young otter cubs playing in the riffles and pools. The sound of bankside vegetation shows that they have left the water, moving through the thick cover and into the wet woodland that pushes broodingly up against the river. They are heading downstream, perhaps to the old swimming hole, and I decide to reposition myself further along.

The otters are moving surprisingly quickly and are back in the water ahead of me – so much for getting ahead of them. Big, globular bubbles float on the surface as the cubs roll and dive and play. I fire off some shots on my camera – the light not too good but I hope just about good enough. I can, at least, delight in seeing them at play. A litter of four cubs is particularly good (two or three cubs is the more usual number) and these feisty individuals must be at least 15 weeks old.

The otters have spotted something, the mother alarming with a short and rough ‘hah’. It’s not me but a large black dog on a lead that, having seen the otters, lets out a bark. This is enough for the otters and again they take to the cover of the wood, all the while working their way downstream. I follow their lead and am rewarded a few minutes later by the sight of them slipping back into the water just above the swimming hole. Soon it is all over, the otters out of sight, but a magical few minutes nonetheless.