Wednesday 22 February 2017

'The times they are a-changin’ - NWT Thorpe Marshes

Naturalist and Norfolk Wildlife Trust volunteer Chris Durdin reflects on 'new nature' and how wildlife responds to climate change at Norfolk Wildlife Trust’s Thorpe Marshes reserve on the edge of Norwich in Thorpe St Andrew.

Approaching dusk in February, and there’s a loud burst of song: a Cetti’s warbler
Cetti's warbler by Elizabeth Dack
. It’s an unremarkable record in 2017 for this bird, unusually among warblers a resident species.

But it’s a reminder of how wildlife responds to changes in climate. Cetti’s warblers first bred in Britain in Kent in 1973 and they soon moved into the Yare Valley. Broadland is now a stronghold and they are also found in wet scrub in much of the south and east of the UK.

There are plenty of other examples of ‘new nature’ on my local patch. We see little egrets fairly regularly. The first little egret I saw, in my student days, was in the Camargue in the south of France, and I can clearly recall my first in Norfolk, on Breydon Water, years later. Today it’s a distinctive and easily-recognised Broadland bird. Like Cetti’s warblers, numbers can be hit if there is a long cold spell, but how often do we get weather like that?

The Migrant Hawker dragonfly was once known as Scarce Hawker, and the new name came after regular appearances in the UK in the 20th century. Now well-established as a breeding species, it’s often the commonest dragonfly at Thorpe Marshes in late summer and with luck you can see them laying eggs. 


Speckled wood butterfly by Elizabeth Dack
More recently arriving still is the Willow Emerald damselfly, breeding in Britain for just a decade, but in good numbers at NWT Thorpe Marshes, elsewhere in the Broads and beyond. The northward spread of the speckled wood butterfly is another example.  


Losses related to climate change can be more difficult to pin down. Snipe used to ‘drum’ – their distinctive breeding display – at Thorpe Marshes when I first knew the area but have stopped breeding here, as in much of lowland England. Climate is probably partly at issue, but also subtle habitat changes. Willow warblers are getting scarcer, and cuckoos too, but for these and other birds that winter in sub-Saharan Africa other factors play a part.
For me, spotting how wildlife responds to changes in climate is obvious: what my eyes and ears reveal backs up what climate scientists say. Perhaps the climate change sceptics are less in tune with the natural world. Writing here, I hope I am preaching to the converted … and that naturalists everywhere will use the evidence of nature to challenge the cynics and doubters.

Discover Thorpe Marshes
Chris leads monthly wildlife walks at NWT Thorpe Marshes. Details of these and recent sightings on the reserve are on www.honeyguide.co.uk/thorpemarshes.htm. The website also has the 15-page NWT Thorpe Marshes Wildlife Report for 2016.

Thursday 16 February 2017

Winter wildlife magic at Hickling Broad

Wildlife enthusiast, blogger and NWT Volunteer Barry Madden braved the bitterness of the east wind on a February evening to watch the spectacular wildlife at Stubb Mill Raptor Roost at Hickling Broad.
A fly past of common crane at Hickling Broad Nick Goodrum

It is cold here. Bitterly cold. A raw easterly wind whipping in from the North Sea a mile or two away; the boundary between the flat lands of eastern Norfolk and the miles of cruel grey water marked by a line of raised dunes seen as a smudge of dull green on the horizon. The scene before us a patchwork of reed bed, course grazing marshes and fen, interspersed with twisted and stunted hawthorn. The closest you can get to a barren wilderness in this part of the world for there are but scant traces of human activity: a forlorn and long abandoned wind pump, its skeletal sail arm pointing defiantly skywards; a single distant house rendered almost invisible by its light-coloured walls blending seamlessly into the gathering murk. Nothing else, just the wild open landscape unique to this Broadland haven at Norfolk Wildife Trust’s Stubb Mill Raptor Watchpoint at Hickling Broad

Us five friends have trudged to this spot, nothing more than a raised bank bordering a drainage dyke, to witness one of nature’s most thrilling and humbling spectacles; the winter roosting of the harriers. We are quite early, 90 minutes before true dusk, but already the leaden, squall-laden skies are casting their shadows over the marshes. Light is poor, visibility far from ideal, but we know the birds will come to seek out this quiet sanctuary to spend another bitterly cold night. And we don’t have long to wait before harriers sail in. First a dark marsh harrier, then a brighter male both gliding on slightly raised wings, buffeted this way and that as they cruise low over the boggy ground. Then delight; a ringtail hen harrier, its bright white rump shining as a beacon through the gloom. A flock of fieldfares appears in a nearby tree and jinking parties of smaller birds, perhaps finches or maybe yellowhammers, are flushed by a buzzard which perches atop a bush before joining another pair of harriers purposely heading towards their roosting zone.

Whilst our attention is focused on the raptors, a pair of common cranes glide over us, dropping down into a hidden pool where they are instantly consumed by the tall ranks of thick reed; lost to sight. These birds are doing well here, naturally arriving as a party of 9 nearly 40 years ago they found the place to their liking and took up residence. Slowly and painfully, with many false starts, the birds began to breed until we now have over 40 gracing the rich and fertile acreage around Hickling and Horsey. In recent years maybe 10 or so pairs attempt to raise young with varying degrees of success, allowing the birds to expand their range into other Broadland reserves and further afield into neighbouring counties. This success story owes all to the sterling efforts of NWT, other local conservation bodies and landowners. Cranes have recently been artificially reintroduced to Somerset, but it must be remembered that in this remote corner of Norfolk where the harriers circle over the reeds and the bittern still finds refuge, we have had majestic cranes for decades. And they always manage to thrill us.


Hen harrier by Elizabeth Dack
Things begin to hot up now with more harriers drifting into view, amongst them a simply beautiful, ghostly grey, resplendently perfect, male hen harrier. What truly gorgeous creatures they are, these birds of wild open spaces. This one drops to the ground seemingly finding his supper, an unlucky pipit perhaps, before he reaches the roosting zone. Through my telescope I can just make out his head tugging at the flesh of the prey he has caught. Such rare birds these and we are privileged to be able to see them in such a setting.

On past visits, on milder, sometimes even bright, winter evenings, the harriers, merlins, barn owls and cranes can put on a wonderful show with massed spiralling as a new bird joins the throng. Merlins arrow into the roost and will happily harass the much bigger harriers, chasing them across the vast open sky in sport. They choose to spend the chill of the night perched atop small hawthorn bushes whereas the larger raptors will roost on the ground or on low branches of dead and broken willows. The owls quarter the fields silent and relentless whilst the sky slower darkens and the stars come out to play. Not today though; the wind chill is numbing our hands, cutting through coats, hats and gloves and making our eyes water. We decide we have seen enough and head back along the narrow, lonely lane to the reserve centre where it is evident much activity is taking place to update and refurbish ready for the coming summer season.

Before this place became more well-known, I used to walk back alone along this lane, bordered by high dark hedges, with all kinds of ghoulish fancies running through my mind. I defy anyone to make this lonely journey and not look over their shoulder every 100 yards, just in case there may be something following; a darker shadow amongst the gathering gloom, an echo of footsteps or an unnatural rustling in the bushes. Hard not to speed up against all reason to reach your car before darkness falls complete. It is the workings of M R James; the fleeting glimpse of something unholy, for nobody knows you are here and your screams will be lost amidst the howl of the wind.

For us five folk though, chatting as a group, we had no such concerns. We instead were lucky enough to see three more cranes, a family party probably, fly towards the broad before we sought welcome refuge ourselves in the warmth of the local pub. Back to civilisation, cosy and comfortable, whilst close by there were the harriers roosting in the reeds, steeling themselves silently against the chilling bitterness of a moonless February night.   


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Tuesday 7 February 2017

Exploring layers of history in the Norfolk Claylands

January may not be abundant with wildflowers but there is plenty to discover on a winter's walk as Helen Baczkowska, Conservation Officer with Norfolk Wildlife Trust records in her Claylands Diary for January.
 

Although I am an enthusiast of wild flowers, January walks are strangely a joy; for once I am not distracted by the delights of stitchwort or speedwell, by trying to sort greater from lesser bird’s foot trefoil.  Instead, I can look out on landscapes, study bare trees and cold winter ponds with a different eye.

On a walk through the heart of the Claylands Living Landscape, my brother, an archaeologist, slowed us down by lightly kicking at molehills. One revealed the treasure he sought – a thin, curved blade of flint I would not have looked twice at.  The chipped edge he showed me was human made, one of the thousand upon thousand Mesolithic flint tools discarded across these lands.  Most, he explained, were found on dry sandy soils, the reasons uncertain, yet how, he asked, had they recognised these places?  For an ecologist, this one question begs many more about how the vegetation of Britain developed as the last glaciers retreated to the north and as herds of large herbivores, from prehistoric bison, to deer and ponies, spread out across the cold steppe grasslands and scrub.
Gorse by David North
   


One thing I could certainly say is that even today, the patches of sandy soils left on the edge of the ice sheets can be easily distinguished amongst the ground up chalky clay of South Norfolk; earlier walking over the County Wildlife Site at Wood Green, we had crossed an area of gorse and fine grasses, visible even in winter.  In summer, heath bedstraw and heath speedwell grow here, although most of the common is clay, with meadow vetchling, meadow buttercup, cowslip and black knapweed.

Nearby Fritton Common is a Site of Special Scientific Interest, with orchids and ponds were great crested newts breed, but in the bleakness of January, my attention was drawn to the almost straight rows of oak trees, most noticeable on the western boundary.  Some of these are huge old trees, the largest in the south-west corner showing signs of pollarding – a way that small wood was once produced by cutting and re-cutting above the height of grazing stock. Collecting small wood from pollards was often the right of the commoners, whereas the timber trees themselves were the property of the lord of the manor. 


Old oak tree by Brian Beckett
In the centuries when barns and houses and especially warships were built on oak frames, these trees were valuable, their management and planting central to a farm’s income and survival; it is likely that the amount of oak across many English counties is not a virtue of ecology, so much a legacy of old economies and the insatiable need for timber for ships.  Today, being winter bare, these trees make curious shapes, with a large, gnarled trunks and many holes; invertebrates inhabit the crevices and barbestelle bats, which are have been recorded hunting over the common, no doubt find a roost in the cracks and fissured bark.

The lines of pollards continue south of Fritton Common, along a sinuous path, known locally as Snake Lane.  Hedges in the Claylands are often tall, with mature trees and a flora suggesting these are old fragments of woodland. The wide hedges of Snake Lane indicate long generations of woodland management, with pollards of oak and field maple; between them the pale slender trunks of hazel show signs of past coppicing.  Like pollarding, this produced small wood for hurdles and tool handles by cutting and re-cutting, but this time at ground level; the re-grown trees have many stems and a distinctive stump or “stool”.  A few hornbeam grow here too, their bark smooth and twisted into long creases, their timber once famed for its hardness.

Returning home, across Morningthorpe Common, a whisper makes me look up.  With a sound like the lightest of summer breezes in tall trees, a flock of fieldfares is heading to roost.  I have spotted a lot of these large, grey-backed thrushes over the past week, no doubt forced briefly south by cold weather. 
Fieldfare by Elizabeth Dack
 

By the end of our walk, dusk is wintry, grey and damp; warmth and hot tea beckon, but so do more days of walking the quiet, hidden tracks of the Claylands, exploring the endless, inseparable layering of human and natural history.