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Chorleywood and District Local Group

Newsletter No. 84 February 2017

www.rspb.org.uk/groups/chorleywood

Group News

This year marks our 40th Anniversary. We propose that we celebrate in September, at the start of the next season, with a lunch in a local pub, most probably The Cock, in Sarratt. This will be preceded by a walk in the Chess Valley to see what wildlife and flora are around then. Or members can just come for the lunch! You will hear more about this idea later in the year.

Happily, we now have filled one crucial vacancy and are very pleased to report that Mary Coulson will be organising the Indoor Programme in the future. Also, Evelyn Fox has agreed to join the Green sandpiper. Birds were tracked to Norway in Committee. So thanks are due to both of these ground-breaking local research project. members. Photo: Luke Massey courtesy of Herts and Middlesex Wildlife Trust - see page 4 At the last Committee meeting in January 2017, we decided that we can now afford to donate £500 to The forthcoming programme contains some very RSPB funds. We chose to allocate this to interesting topics. How did birdwatching in WW11 calcareous grasslands and blanket bog, both rare prisoner of war camps lead to influence in the habitats. Please do try to attend meetings when you RSPB and BTO? Why have we never seen a can, for the RSPB needs our help as never before. goshawk? All will be revealed at our talks in Once again, the latest State of Nature Report February and April. Our coach outing will be to shows deteriorating numbers of many bird species. Rutland Water where we should see ospreys on But there have been successes - in the their nests and much more besides. Save the date conservation of bitterns, cirl buntings, cranes, of 13 May in your diary. Thank you for your bearded tits and lapwings on RSPB reserves. Read continuing support. about this on page 2. The Committee

We have sad news for those who knew Harold CONTENTS Price, one of the founder members of Chorleywood RSPB Group, who died in December 2016. In 1977, Little Egret Research ...... Page 2 Harold was one of the first committee members at a Good News Stories from RSPB ...... 2 time when work was done by handwriting and Local and National Events ...... 3 telephone. He was Group Leader from 1980 for Book Launched on Herts. Butterflies ...... 3 8 years and steered the Group to its heyday. The Research in Herts. on Green Sandpipers ...4 current shape of the Group is largely due to Lemsford Springs Reserve ...... 5 Harold’s work. Several of our members attended his News from Local Reserves ...... 6 funeral in January. Your Photos ...... 7 Outdoor Meetings ...... 8 1

Little Egret Research

Help needed to spot colour-ringed little egrets

Have you ever wanted to help with a bird research project, but worried that you don’t have the identification skills or the opportunity to visit far flung places? Here is a project that may be suitable for all of us. Everyone can identify a little egret! There are lots in our area, for example, along the Little egret Chess Valley, at Stockers Lake, at the Aquadrome Artwork, Mike and on the River Colne. Some of them are used to Langman humans and stay close to river banks. rspb-images.com

There is a national scheme for colour-ringed little egrets. Help is needed to identify the colours of the leg rings and, if possible, the numbers on the rings. All observations would be of considerable value. It is always a good idea to carry with you a small note book because we must accurately report the Good News from RSPB following points:- Crane chicks fledged successfully in the  Note the colour and position of each ring, West Country including which colour is on which leg This was a milestone moment for the Great Crane Project when four chicks successfully fledged in  Note the digit which is engraved on the 2015. This is the first time in 400 years that cranes colour rings have successfully bred. Nine pairs bred initially, with four of these pairs going on to hatch and rear  Note the location and time and date of chicks. Four survived to fledge! observation 50 pairs of cirl buntings are now in Cornwall If you see any orange rings on the left tibia, the bird After reintroductions, there are now 50 pairs of cirl has been ringed in SE England and they are very buntings. This is the first passerine reintroduction in likely to be local birds, including ones ringed in Europe and confidence is growing that the numbers at Lemsford Springs, Stanborough will continue to increase. It demonstrates that Reed Marsh and Verulamium. wildlife friendly farmers can change the fate of declining farmland species. This is a useful job that we can do and please report your sightings to one of the following:- Booming bitterns increase again Throughout the UK in 2015, the number of booming Mike Reed ([email protected]) or bitterns increased to a minimum of 155 recorded at 70 sites. This represents the highest number in Barry Trevis ([email protected]) living memory. Churring nightjars also reached their highest ever level on RSPB reserves. And on RSPB Or let any member of our Committee know and we lowland wet grassland reserves, breeding lapwings will pass on your findings. and redshanks also reached their highest ever level! Only 132 little egrets were ringed in 2015 in the whole of Britain and Northern Ireland, so do not Keep buzzing expect to see many. But only by ringing can survival Short-haired bumblebee releases have continued at rates and movements be monitored. Dungeness. Worker bees have been seen there this year for the fourth year running.

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Local and National Events

Date

Saturday, 11 March 2017 Herts Bird Club/BTO Conference. Affinity Water, Hatfield. 2-5pm. Cost £5. Programme of speakers to be announced

nearer the date. See website www.hnhs.org/birds

Thursday, 6 April 2017 Friends of Stockers Lake AGM. Rickmansworth School, 7.30pm. Speaker: Lesley Davis, Director of Herts & Middlesex Wildlife Trust. The Work of the Trust and its Five-Year Plan.

21 to 23 April 2017 RSPB Weekend. A great programme of talks, seminars and workshops, plus excursions on the Friday. RSPB shop and exhibition. Huge choice of talks and seminars. East Midlands Conference Centre in Nottingham University grounds. Booking opens in January 2017. Go to www.rspb.org.uk.

Sunday, 7 May 2017 Stockers Lake Spring Chorus and Warbler Walk. 8.30am. Meet on the Causeway between Bury and Stockers Lake. 1.5 miles, duration 2.5 hours.

18 to 20 August 2017 Bird Fair at Rutland Water. The event of the year for wildlife enthusiasts with 100s of sales stands, a fantastic variety of lectures, wildlife art, optics, quizzes and question and answer sessions. Tickets available from March 2017. www.birdfair.org.uk

trends over almost 40 years. More than 4,800 local Butterflies of Hertfordshire and enthusiasts contributed to the latest survey, which Middlesex covers changes up to 2015.

The secrets of Hertfordshire’s shifting butterfly populations and their place in our changing countryside and towns are revealed by a new book published in November 2016.

Butterflies of Hertfordshire and Middlesex by Andrew Wood, Hertfordshire’s official butterfly recorder, provides a comprehensive guide to every species currently found in the two counties – and considers the reasons why some are increasing, while others have declined or disappeared altogether.

Climate and landscape changes, together with lessons drawn from the hits and misses of conservation measures, feature in the 272-page book, which is lavishly illustrated with locally-taken photographs and population maps that illustrate

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Among the success stories is an account of Three Butterfly Hotspots in Hertfordshire Hertfordshire’s ‘flagship’ butterfly, the Purple Emperor (whose trademark sheen is only revealed  near Tring: this has more in males when their wings catch the light.) From just species recorded than any other site in our one record near Hitchin in the 1980s, the species is county. The rare Green Hairstreak, Dingy being reported from a growing number of locations, and Grizzled Skippers, Dark Green Fritillary including Whippendell Woods in . and Small and Chalkhill Blues are all found here. The book also describes how one of Britain’s rarer  between butterflies, the Chalkhill Blue, has been restored to St. Albans and Watford: this is a good relative abundance on Heath near place to find spectacular woodland Royston after a worrying decline a decade ago. It butterflies such as the Purple Emperor, also explains how its relative, the Small Blue, White Admiral and Silver-washed Fritillary. which was thought to have disappeared from  Heartwood Forest north of Hertfordshire, has established thriving colonies  St. Albans: here the White-letter and Purple outside St. Albans at the site of the now-closed Hairstreak butterflies have been found as ‘Butterfly World’ venture – and on the edge of well as grassland species. Letchworth.

Green Sandpiper Tracked on Non-stop Flight from Herts and Middlesex Wildlife Trust Nature Reserve to Norway

Barry Trevis, Volunteer Warden from Herts and Middlesex Wildlife Trust, tells us about their exciting discovery this summer.

A cutting-edge bird-tagging project using GPS tags has tracked a green sandpiper, a small wading bird, from Hertfordshire all the way to Norway and back. GPS tags weighing only a gram have been fitted to green sandpipers over the last four years to find out where birds from HMWT’s Lemsford Springs Nature Reserve (near Welwyn Garden City) go to breed. The mini-computers record the birds’ positions in the world at pre-set intervals during the breeding season. From April to July this year, one bird was tracked on a non-stop, 900km flight to Norway over the breeding season – and all the way back again to Lemsford Springs.

‘White-on-Green’, the star of the study Barry Trevis, Volunteer Warden at Lemsford Photo: Barry Trevis Springs Nature Reserve, said: “This April we fitted a green sandpiper with a GPS tag. Data from the tag From the end of April to mid-June the bird moved to shows that the bird was at Lemsford Springs Nature North Norway near Trondheim to breed. After being Reserve on 26 April and arrived on an island off the tracked to a small lake between Hatfield and coast of southern Norway called Store Saesöy just St. Albans on 21 June, it was next seen at two days later. These dates indicate that it would Lemsford on 15 July. I was able to recapture the have made a non-stop flight across the North Sea. bird on 30 July, when the tag was removed and the sandpiper released. We have seen the sandpiper regularly on the lagoons since then.”

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Laura Baker, Herts and Middlesex Wildlife Trust’s seen here for most of the year apart from April to Lemsford Springs Reserves Officer, said: “The mid-July. To visit, a key must be obtained from the tracking of a green sandpiper all the way to Norway warden, Barry Trevis, who lives near the reserve. and back is very exciting. It really goes to show Phone: 01707 335517. It is a small site (4.5 ha) with what can be achieved in conservation when tried two hides (and a chemical toilet). and tested methods are teamed up with new science. We now have a greater insight into how far It is on the site of an old watercress bed and is these birds travel – quite a distance, it turns out! We surrounded by woodland, meadow and marsh. will continue to monitor the green sandpipers and From 1860 until 1966, watercress was harvested all use this information to help us manage the reserve year round and sold at Covent Garden in London in the best possible way for the birds”. and at local markets. Watercress is a native plant and still grows in the lagoons today. Barry and his team of volunteers have found out that if they rake Tiny this cress into piles, millions of freshwater shrimps GPS flourish underneath as they eat the cress. tag, weight The springs that feed the lagoons are always at a 1gm constant temperature and never freeze over. So Photo: there is always a supply of food in the form of fresh Barry water shrimps, snails and fish for birds, including Trevis snipe, water rail, green sandpiper and kingfisher. This means that a good time to visit the reserve is when the temperature is very cold. Up to 20 green sandpipers have been seen here in these

conditions when other wetlands are frozen over. Lemsford Springs Nature Reserve is a very special Bright and cold conditions can attract many site in the UK for wintering green sandpipers. Last photographers, so it is best to go when it is cold and year 85 tonnes of gravel was distributed here to dull! improve the specialised habitat of the cress beds. The watercress supports a large number of freshwater shrimps, welcome food for our green sandpipers and lots of other wildlife. We will be continuing this work and look forward to welcoming more people to the reserve so we can show them how special this place is for wildlife.

Green sandpipers have been the subject of a long- term study at Lemsford Springs since 1983, led by local experts Barry Trevis, Ken Smith and Mike Reed. The birds are known to spend up to 10 months a year on the reserve and nearby wetlands, many returning year after year. Green sandpipers usually migrate to Northern and Eastern Europe to breed, with just a few pairs recorded On a misty morning at Lemsford, by Anna Marrett breeding in northern Scotland. It is amazing how many nest boxes that Barry www.hertswildlifetrust.org.uk manages to site on this reserve. They have been occupied by mandarin ducks, barn owls, tawny owls More About Lemsford Springs Nature and kestrels to name a few. Reserve Carol Smith

Just a couple of miles north of Hatfield lies a gem of a small nature reserve, owned by the Herts and Middlesex Wildlife Trust. Lemsford Springs has become famous recently due to the research into the migration of its green sandpipers, which can be 5

NEWS FROM LOCAL NATURE RESERVES

Stockers Lake, Rickmansworth

Winter 2016/17 sightings include barnacle goose, great white egret, red-crested pochard, smew, goosander, goldeneye and 8 whooper swans.

Bird report 2015 (published late 2016)

Oystercatchers bred successfully again, common terns had great success this season with at least 15 breeding pairs and little egrets continue to breed on the islands. Lesser spotted woodpecker stayed in view in the spring using an oak as a regular drumming post. Barn owl and water pipit were sighted for the first time in years. Egyptian geese are increasingly common and red-crested pochards are now a well-established resident. But smew and goosander are in decline as winter visitors and cuckoos are declining as summer visitors. Kestrel numbers are also in decline, but it is suggested that a nest box might help. Red kite and ring-necked parakeet are now common residents.

The lake is owned by Affinity Water and managed by the Herts. and Middlesex Wildlife Trust. They are greatly helped by Friends of Stockers Lake. It has the largest heron roost in Hertfordshire and hosts important numbers of winter ducks and waterfowl. Insects and wildflower abound here. There is free access to the reserve, which is alongside the with its car park, café and toilets.

We recommend that you join Friends of Stockers Lake for £5 per year. There are regular working parties in the winter and you will receive newsletters with full bird reports. The AGM in 2017 will be held on Thursday, 6 April, in Rickmansworth. There will be an interesting talk from Lesley Davis, Director of Herts and Middlesex Wildlife Trust. See www.FoS L.org.uk

Maple Lodge Conservation Society, Rickmansworth

Highlights of 2016

Star billing must go to the osprey, which was fishing in Marsh Lake for several days in August and September. No doubt it was en route to the African wintering grounds. Barn owls were seen entering and leaving the nest box. Low water levels encourage visits from common and green sandpipers, greenshank and little egrets.

Maple Lodge is a private nature reserve. In other words, to gain access via the comfortable clubhouse, you need a padlock code only available to members. It consists of several lakes and meres, woodland and grassland and has a few hides. There are a band of volunteers who maintain the reserve and show visiting groups round. Insects, bats and wildflowers are studied and protected along with up to 90 different species of birds.

Throughout the year open days are held for visitors and to encourage new membership. Have a look at their excellent website www.maplelodge.org or for membership enquiries email [email protected] Annual individual membership is £17 for an adult.

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Your Photos (Email [email protected] )

Above and left: Martial eagle, marabou stork and barred owlet in South Africa, 2015. Photos: Vaughan Ryall

Below: Sparrowhawk in Mary and Pete Coulson’s garden Photo: Pete Coulson

Left: Open Air Hyde at Middlesex Waterworks Centre Photo: Tony Wright

“This genre of photography is called a Planet Panorama. I use Photoshop to create it, but I expect other software will do it. You start by photographing and creating a “normal” pano rama. As in the Waterworks case, it need not be a full 360 degrees sweep, but the ends will need to match reasonably well in content and height. Next, stretch out the image vertically to form a rather weird looking square photo. Turn this image upside down, which will ensure the sky is on the outside and apply the “Rectangular to Polar” conversion process in the editing software.” TW

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Outdoor Meetings

Tyttenhanger Gravel Pits, Colney Heath the barge and on the land we could observe hundreds of winter migrants. Saturday, 17 September 2016 We boarded the barge at The Hythe, in Maldon. In the London birding world, this destination is one Several historic boats were moored there, but only of the most famous sites because it attracts the our barge, Hydrogen, set sail on this particular second largest species count after Rainham Sunday. The trip was run by Essex Wildlife Trust Marshes. But September is not the best month in and needed to be pre-booked from Topsail which to see birds in our area and we found very Charters. few. Many swallows and house martins were still around. We also saw the first of the mixed flocks of tit species common in the winter months. On the lake were a few greylag and Canada geese plus coots, but it was all rather quiet. Tree sparrows occur here too, but they were hiding today. We must return to this destination at a better time of year.

In focus Shop, Willows Farm Village, Coursers Road To visit Tyttenhangar Gravel Pits, we had parked at the Willows Farm Village site where there happens to be an In Focus shop. Tony had arranged for the manager of the shop to speak to us about the latest developments in The Hythe, with our barge, Hydrogen, on the left telescopes and binoculars. For example, the Photo: Dave Smith lugging of weighty telescopes should become a thing of the past. Nowadays much smaller, lighter On arrival at The Hythe, we could see a narrow ones give similar results. We were able to look island just offshore. Hundreds of black-tailed through some of these. Tripods are still required, godwits, newly arrived from Iceland, were flying however. down to the far side of the island to feed, hidden from us. Their numbers are increasing. As we Smart phone scope adapter sailed around the estuary, many small dark-bellied The manager also showed us the new Smartphone brent geese flocks were seen and these had just Scope Adapters. With the popularity of smart arrived from Siberia. They stay all winter on the phones that have good cameras, the makers of Essex rivers and coast. Dunlin flocks whizzed past telescopes have developed a housing that enables us and some Egyptian geese were seen on the you to fix your phone to the eyepiece of a shores of the creeks and flying past us, their white telescope. This is a small, neat piece of plastic and upper wing markings helping identification. There simple to fix and use. So alongside your lightweight were many little egrets too and avocets flying in telescope, and tripod, you need only a smartphone synchronised flocks. and its adapter to take good photos of distant birds. Unfortunately, gusty winds meant that only a few sails could be unfurled and mostly we had to use The Blackwater Estuary, Maldon, on motor power. As we neared the moored barges at the Thames Sailing Barge, Hydrogen Maldon, we saw that their rigging provided useful Sunday, 16 October 2016 landing sites for the numerous starlings that were flocking over the riverbank prior to finding an This experience was fascinating for all, whether for overnight roost. the sailing or the birdlife. We realise now why the Essex river estuaries are well known as valuable We returned to Maldon after lunch on board. The winter refuges for so many bird species. Both from skill of the captain and two crewmen impressed us 8

as they squeezed in their huge boat on to the quay was observed fliting around the vegetation in the - parallel parking of the extreme kind! Then we shallow waters of a flood relief channel. Our route walked along the quayside until the falling tide then took us onto the Walthamstow Marshes, which exposed the mud of the shore. A flock of golden along with the adjacent Hackney Marshes are the plovers landed near to us to feed. Also we saw last few remaining pieces of the once widespread many little ringed plovers here, teals, lapwings and Lea River valley grassland. These fragments still dunlins dashing over. The Essex Wildlife Trust had support about 60 species of birds many of which provided a telescope to enable us to see these can be seen in passage, but 25 species breed in shore birds well. One good thing about this location the region. and the estuary in general is that there are footpaths all along the shore, providing good Here the crows, that had been vigorously chasing a viewing of the wading birds. sparrowhawk over the Waterworks in the morning, turned their attention to a kestrel that sought refuge Walthamstow Marshes and Middlesex on the balcony of a canal side apartment. The open grassland held a few small birds, including a Water Works Nature Park stonechat high on a bush and a flock of goldfinches Saturday, 19 November flying by.

Nine of us made the trip down the M11 to part of Here is a list of the 29 bird species seen as compiled by Peter Harman:- the River Lea Valley Regional Park, just north of Robin, dunnock, blackbird, stonechat, ring-necked Stratford, East London. We parked in the Middlesex parakeet, tufted duck, pochard, jay, mute swan, mallard, Water Works Centre car park, where there is a café coot, moorhen, wigeon, little grebe, teal, blue tit, and Nature Park. Although not large, the Centre chaffinch, goldfinch, grey wagtail, Cetti’s warbler, great plays a large role in bringing wildlife to the local spotted woodpecker, black-headed gull, cormorant, community with several teaching areas, easily wood pigeon, magpie, crow, house sparrow, kestrel. accessible paths and several sculptures in the park. , in Fog Saturday, 17 December

The fainthearted would have retreated to the Bluebell Café, but led by Tony Wright we plunged on to the mist-shrouded paths surrounding the three reservoirs. These are Marsworth, Tringford and Wilstone Reservoirs, hand dug to store water for the Grand Union Canal. To our surprise, the lakes were very crowded with ducks, which prefer our milder foggy weather to that of the cold arctic tundra of Iceland, Siberia and northern Scandinavia.

Teals and a moorhen Photo: Andrew Case So, though the colour of the plumage was dulled by It boasts one of the largest hides in London. This is the fog, we could identify many migratory species, a round structure built on the central section of the such as wigeons, teals and pochards. Cormorants, old filter beds with sheltered windows overlooking mallards, coots, moorhens and great crested the beds. See photo page 7. Each bed is cleverly grebes too were out in force. Far away, in the managed to show how the they have returned to middle of Wilstone Reservoir, we could vaguely nature over the last 50 years - open water giving make out stationary lapwings on the spit. way to reed beds to scrub and finally a willow woodland. The wildlife responds and diversifies into Perhaps grounded by fog the ducks kept to the these varied environments, although in winter the water, the wigeon making their romantic whistling main area of interest was the open water with a call. On surrounding fields and hedgerows we saw good variety of ducks, including pochard, little little, except the occasional blackbird, mixed tit grebe, moorhen and many beautiful teals flocks, jackdaws and greylag geese. Later many resplendent in the sunshine. redwings were found between hedges and fields.

After lunch in the Centre’s excellent little café we The Grand Union Canal towpath gave us an crossed the Lea Bridge Road where a grey wagtail alternative route back and here we had delightful 9

views, four times, of two kingfishers, either flying Goldeneyes of both sexes, a few pochards and over the water or resting in low branches. Also lapwings standing on some of the newly cleared here, at the water’s edge, in dense hedgerows, islands were clearly seen in middling brightness. were two beautiful goldcrests, clearly visible and also a lone heron. In the riverside hedgerows and trees were song thrushes, robins, blackbirds, ring-necked parakeets, List of 36 species seen compiled by Peter Harman. great, long-tailed and blue tits and goldcrest. Robin, redwing, blackbird, starling, fieldfare, grey wagtail, pied wagtail, blue tit, chaffinch, great tit, goldfinch, long- We enjoyed our stroll, but many exciting birds were tailed tit, dunnock, tufted duck, pochard, great crested absent in this, as yet, mild winter. No siskins, grebe, mute swan, mallard, grey heron, moorhen, goosanders, smews or kingfishers were seen. As wigeon, lapwing, teal, coot, shoveler, black-headed gull, cormorant, wood pigeon, magpie, crow, jackdaw, greylag we know from previous years, the best time to visit goose, lesser black-backed gull, kingfisher, collared is in really cold and icy conditions, when the water dove, goldcrest. birds are often concentrated near the water’s edge due to the ice. Traditional Stocker’s Lake Walk New Year’s Day, 2017

Every year on the lake is different. This time, the huge numbers of male and female gadwalls, coots, wigeons and up to 15 red-crested pochards made the greatest impression on us. The lake was just covered in birds. Shovelers and black-headed gulls were also very numerous. One of the great crested grebes still had his striped neck, so he was a juvenile, but able to catch and eat a fish in front of us.

We were very lucky to see the red-crested pochards, because very few are in the country. Most of the Stocker’s birds were thought to have escaped from captivity, perhaps also boosted by the occasional continental bird. The Stocker’s birds managed to breed in 2013, but not since. According to the RSPB website, only around 20 at most have bred in this country, while around 300 are present in Britain overall in winter.

Much duller than the male, this is the female red-crested pochard Artwork: Mike Langman, rspb-images.com The Royal Society for the Protection of Birds (RSPB) is a registered charity: England and Wales The gadwall is found all year round in Britain, but No. 207076, Scotland No.SC037654 numbers are boosted in winter with northern European and Icelandic birds. Exactly the same Any advertisements enclosed with this newsletter applies to coots, which are easily overlooked. They are not specifically endorsed by the RSPB or the too can be migrants. Chorleywood and District Local Group

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