Tuesday, 29 September 2015

In for the count

Chris Durdin, NWT Thorpe Marshes

Three of us who visit NWT Thorpe Marshes regularly have been making a point of counting orange-tip butterflies and Norfolk hawker dragonflies.

The idea is to do simple, repeatable ‘transects’, with a view to finding out how these species are doing from year to year. Orange-tips and Norfolk hawkers were chosen as they are key marshland species while also being fairly easy to see, identify and count. We noted what was seen on various sections of the regular circuit around the marshes, alongside simple weather data.

Orange-tip butterfly, photo by Chris Durdin
Orange-tips, though they also come into gardens, link strongly with the grazed marshes at Thorpe as that’s where a favourite larval food plant grows, namely lady’s smock – also known as cuckoo flower or milk maid. The time for orange-tip surveys was April and May, with the highest count on five survey visits being 17 on 11 May. Of course weather and when, as volunteers, we are free to visit both play a part in results. From past experience we can expect to see many more orange-tips if a visit is made on a warm day in late April.

Norfolk hawker dragonfly, photo by Chris Durdin
Norfolk hawker dragonflies are a good indicator of the quality of the wetland’s ditch system, and June and July are the key months. Derek Longe saw 39 Norfolk hawkers on 24 June, but that was topped by Susan Weeks who recorded no less than 46 on 30 June, the peak count from 12 survey visits. That’s a reminder of what a fine place Thorpe Marshes is to see dragonfly that is the emblem of the Broads Society, all the more surprising on the edge of suburban Norwich.

These survey results on their own are little more than snapshots of the nature reserve, we know, but we hope that patterns will begin to show if we can build a data set over a few years.

Chris Durdin leads monthly wildlife walks at NWT Thorpe Marshes. Details of monthly walks on http://www.honeyguide.co.uk/thorpemarshes.htm

Wednesday, 16 September 2015

A place in the heart

David North, Head of People and Wildlife

I’ve fallen in love with a new place and the blame lies with a kingfisher. Home Meadow is part of the Mannington Hall estate and is a place I have occasionally visited in the past as it’s just a couple of miles from where I live.

Home Meadow, photo by David North
About a month ago I was out walking and decided to pay Home Meadow a visit. There’s a small hide that overlooks a beautiful quiet pond surrounded by trees and on entering the hide a kingfisher shot away from its fishing post just a few metres in front of the hide.  Well always nice to see a kingfisher and even a view of one flying arrow like, low over the water but away into the distance was of course a real treat.

Kingfisher, photo by David North
But five minutes later it’s back. Perched so close I felt I could have reached out and touched it.  An exaggeration of course, but you get the idea. What a joy. Twenty minutes of watching this jewel of a bird perched close enough for me to marvel at each iridescent feather. What a privilege. As it turns in the sunlight its back colours change from vivid turquoise blue to sea-green, though its vivid orange breast remains unchanged. A sighting like this is special and has encouraged me to make Home Meadow a regular haunt over the past few weeks.

These visits have changed my feelings about this place. Though I have seen the kingfisher on several more occasions all have been fleeting and distant views but these more regular visits, and my time spent quietly waiting for kingfishers, have given me many timeless moments, and opened my eyes and my heart to this place’s extraordinary beauty. Never mind a kingfisher but  have you ever watched a heron having a wash and brush up. Another extraordinary 20 minute wildlife show never to be forgotten.

The walk to the hide is along a boardwalk which circles through a very wet meadow. Home Meadow is after all the main player at around 10 acres not the much smaller pond. Though I have walked here before several times over recent years either my eyes have been shut, or perhaps it was not in at this time of year when late summer mistily and mysteriously drifts into early autumn. 

Rose-bay willowherb, photo by David North
Just a few weeks ago, or was it longer, as time moves in strange ways when you are falling in love, Home Meadow was all creamy drifts of meadowsweet and the blousy pinks of rose-bay and hairy willowherb. Then in a blink, or so it seems, it became sculpted with the towering, architectural umbels of angelica standing tall and proud over a sea of red knapweed flowers. Blink again and where knapweeds were dancing red in the wind now a great sea of dark seed heads has appeared and by some strange alchemy the fiery willowherb has turned to silky, silver feather heads. But amongst them, and the show which completed the capture of my heart, sway a thousand mauve-blue blooms of devil’s bit scabious to a background music of soft buzzing  carder bees over which migrant hawker and ruddy darter dragonflies dance  patrolling the flower flyways.

Devil's bit scabious, photo by David North
Home Meadow for the past few weeks has shown me a whole set of wonders – a different mood and new discoveries at every visit. This special place is one of more than 1,300 County Wildlife Sites found in almost every area of Norfolk. They cover a whole gamut of habitats, from woodland to wetland and everything in between. Nearly all have only survived because landowners, Parish Councils, or commoners’ groups have cared and put time and effort into managing them.  In the case of Home Meadow this protection has come from Lord and Lady Walpole of Mannington Estate, who ensure the meadow is cut each year  and have made it possible for visitors to enjoy its quiet and peace without damaging its fragile wetland by installing boardwalks and a small hide.

Home Meadow became a County Wildlife Site in 1991 and the Walpoles created the pond in 1986 adding the boardwalk and hide in 1993. I salute them, and all the other owners and managers of County Wildlife Sites, who play such an important role in preserving and protecting these special places. Special for wildlife of course, but many are also special places for people; full of wonders, of quiet, of beauty and of extraordinary joy.

A bad hair day for this heron? Photo by David North
here are many places I have fallen in love with. Does that make me fickle? But from now on Home Meadow has a place in my heart. A relationship that started in a moment of brilliant blue in a hide, has deepened through chance encounters with herons and is now a place I care for deeply. Perhaps a life long passion.

I hope you too have special encounters with wildlife that deepen into a life-time’s love of place. We are fortunate in Norfolk still to have so many places worth falling in love with, worth caring about, worth sometimes fighting for. In return they, like all good relationships, bring great joy, and if you are lucky and explore with an open hear then you may be rewarded when they touch you with their wildness and bring their mystery and magic to your life. 

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Friday, 11 September 2015

End of the education season

Norfolk Hawker Dragonfly resting on a reed. 
Image by Steph Ford
Steph Ford, Seasonal Education Officer

So here we are at the end of the season! We seasonal education officers will soon be moving on to pastures new, but before we do here is a taster of our experiences with freshwater invertebrates…

Before my time with Norfolk Wildlife Trust I had never seen a spindly water stick insect, a damselfly nymph emerging from its water-soaked skin to bask on a reed, or a dragonfly nymph chomping hungrily on phantom midge larvae. I thought I was well versed in the goings-on of the freshwater invertebrate world, but during my time as a seasonal my knowledge has increased ten-fold.

I have seen how absorbing it is for families to catch a net of squirming invertebrates, to gaze at the life dispersing in their water-filled tray as they empty their net, and to then put the correct name to each of the squiggling creatures. It’s a great chance to observe the behaviour of the species in the trays- greater water boatmen swimming on their backs through clusters of oxygenating pond weed, Pond Snails gliding lazily across the base of the trays, cased caddis fly larvae camouflaging themselves in their hollow stick homes. Looking down from above, it’s like a whole secret world in a white tray; fights, life cycles and hunting all going on, oblivious to us. It’s a window in on a world rarely seen, but constantly challenged by our actions that can either be positive, such as providing new habitats, or detrimental, such as spraying pesticides or fertilisers that end up in the water. I believe letting children into this realm of smooth skins and gnashing jaws gives them an insight into their responsibility of care to these creatures, and may well end up being the beginning of a life-long passion to protect wildlife.

Great diving beetle larvae eating freshwater 
shrimps, photo by Brian Eversham
I have seen A-Level students exclaim in wonder at great diving beetles zipping about in their bug pots, whilst proudly passing around a specimen pot containing a scarlet-chested stickleback. Young children, encouraged by their parents, are allowed to help hold the net and beam in excitement at being part of a family activity that everyone is involved in. Water scorpions, pond snails, water boatmen, freshwater shrimp, water fleas, pond skaters, water mites and newts have all been caught, studied and admired over the summer and (reluctantly) put back by children.  

Male Stickleback, photo by A.J Thursby
It has really bought home to me how accessible nature can be for everyone, regardless of age, background and ability. Some of these children had never dipped before, and after dispelling a few myths (no, we won’t catch a crocodile/shark/dinosaur) everyone got stuck in and I have no doubt will remember their experience for a long time to come.

Wednesday, 9 September 2015

Biocontrol of Water Fern

Nick Carter, Conservation Officer (Fens)

Water fern in storage lagoon
Water fern, Azolla filiculoides, a native of Central and North America was introduced into the UK in about 1840 as an ornamental aquatic plant but has since spread into the wider environment. It can quickly form dense, thick mats of green or red vegetation that block out light, cause de-oxygenation of the water, kill aquatic flora and fauna and interfere with water management. It spreads vegetatively - making mechanical control impossible - and by spores in the autumn.  

It was first noticed in autumn 2012 in the storage lagoon at Hilgay but following the cold winter of 2012/3 it was not noted in 2013. It reappeared in autumn 2014 again in the storage lagoon either from survivors of the original infestation or re-introduction by wildfowl. It grew rapidly to form dense mats which survived the winter and spread to other parts of the site in 2015. The warm weather during June and July resulted in the formation of dense mats again.

Stenopelmus rufinasus adult,
photo by Corin Pratt CABI
Natural help is at hand however in the form of a tiny, native North American weevil, Stenopelmus rufinasus. It was first recorded in the UK in 1921, presumably being present on imported water fern plants. It is considered by Defra (Department for Environment, Food and Rural Affairs) to be ordinarily resident so there are no licensing requirements to release populations where they are not present naturally.

CABI (Centre for Agricultural and Biosciences International) is a not-for-profit organisation which develops solutions to agricultural and environmental issues and is a world leader in the development of biocontrol solutions. It rears the weevil and we have recently bought and released several batches of it in order to get it established at the site before the winter.  As the weevil feeds exclusively on water fern there is no risk to other plant species and is thus a very specific control measure, an advantage over more broad-spectrum chemical control measures.

We will monitor the situation in 2016 to check that the weevils have survived the winter and do further introductions if it looks as though the water fern is getting out of control again. In the longer term it is hoped that the permanent presence of the weevil on site will keep the water fern distribution in balance so dense, extensive mats do not form.

Tuesday, 1 September 2015

Methwold barn owls

Nick Carter, Conservation Officer (Fens)

Colin and Val Shawyer, of the Wildlife Conservation Partnership, did their annual check of the barn owl box on the Methwold Wetland Creation site. They found a mixture of good and bad news. 

The resident pair had found the new box which had been put up so they would not be disturbed by the ongoing construction works. Unfortunately they showed no evidence of breeding this year, in common with many pairs across the country. 

Barn owl populations change in a delayed cycle with their vole prey. Two years ago they had a disastrous breeding season because the prolonged cold winter and low vole numbers meant females were not in good enough condition to breed but last year breeding success was very high because of an abundance of voles. This year breeding success is likely to be low with many boxes occupied by non-breeding birds or pairs producing few young as vole numbers have declined. Next year vole numbers are predicted to hit their trough so the breeding season will be tough for barn owls again but they should bounce back after that. Long-term monitoring is critical to understand what is going on in our countryside and for species like barn owls that have populations that naturally fluctuate it is the only way to study significant population trends.