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September 2012 Newsletter

Tangled up in Knots.
August Bird News.
Forthcoming Events.
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Following colour ringed migratory shorebirds around Europe.

Part 2: Tangled up in Knots.


                     Winter plumaged Knots at Thurstaston above top,  Matt Thomas
                     Summer plumaged Knots at Porsanger, Norway, above bottom,  Matt Thomas


By Matt Thomas

A grey murk hangs low over the Clwydian ridge on the far side of the mudflats, it seems to be sucking the colour from the hills, everything is tending towards monochrome. The mud itself is a hundred shades of grey that seems as short on life as it is on colour. And the cold; fierce and at times aggressive is all encompassing. Any chink in fleecy armour is ruthlessly punished. The wind comes sweeping around the Point of Ayr to amplify the chill, stealing heat and delivering rain. Few would regard this scene as inviting, more one to avoid, but I can’t dodge it. I have to be there.

Last month, after reading part one of this pan-European migration research epic you will know how much I enjoy the study of migratory shorebirds using colour ringing. In fact my enjoyment seems to be blurring into more of an obsession that will see me out on the estuary in the foulest of conditions.

So, encased in several layers of thermal clothing, hat pulled down over protesting ears and double-gloved, I hoist the telescope over my shoulder and trudge down to the shore. The flats that seemed devoid of life at first glance are anything but, and while there are no colour ringed Black-tailed Godwits striding around the inter-tidal mud today, there are still thousands of waders present. Some of these will be colour marked too; Blackwits are not the only species under investigation. Today’s target is Knot.

Matching the greys of the estuary mud with their unassuming winter plumage the Knot, Claidris canutus, can sometimes be overlooked when more colourful or boisterous species are around.

People often ignore the individual Knot only really taking notice when they assemble into a huge flock and take to the air. Traumatized by a Peregrine attack the birds explode from diligent feeding, their take off sounding like a round of applause breaking out. Then, once airborne, their manoeuvres are spectacular, spiralling and jinking in animated waves of charcoal grey they look like a puff of smoke pulled along by the whims of the wind. The sound of so many pairs of wings ripping at the air in unison is like a sheet of canvas being torn to shreds. This is when we seem to appreciate these birds most, in their moments of sheer terror, these episodes often culminating in death for one of the flock.

However, I am more interested in looking at each of this Calidrid congregation one by one. As awesome and inspiring as these aerial shows are I am hoping that the Knot will remain undisturbed for the next few hours so I can search for colour ringed individuals amongst the 4,000 or so birds on the mud in front of me.

Through my binoculars the birds look somewhere between ant-like bugs and beaked mice, zipping at speed across the slick surface of the mud in a variety of seemingly random directions. This makes the idea of finding and reading a colour ring combination on their tiny legs seem fanciful. But, once the tripod legs are splayed and my feet are planted as firmly as the soggy sand allows, I bow my head to the scope, feel the snug rubbery fit of the eyecup and the birds come to sharp focus through layers of polished glass. Now I can see each tarsus and tibia in vivid detail. The hunt begins.

There are six subspecies of Red Knot that breed on windswept tundra across much of the Arctic. The birds before me, like almost all of the birds that visit the Dee in winter, belong to the islandica race. These birds nest in the far north of Arctic Canada and along the coast of eastern Greenland.

Most of these islandica birds will use Iceland as a staging post on their northward migration, but some choose a different route, heading to eastern Greenland and the highest parts of Arctic Canada via a place called Porsanger in Northern Norway. It is the most northerly regular spring staging area for knots in the world. Here birds are colour ringed in an effort to learn more about the origin, distribution and survival of this group of Knots. Some of these birds have been seen on the Dee and it is them that I am looking for.

Each marked bird has a red ring on its right tibia and on the left tibia is a yellow ring with a tab containing a unique 3 letter code. For a complete record all 3 digits must be read in order from left to right. No two codes are the same allowing individual birds to be tracked on their migration. These codes are tricky to read, the birds are swift in their movements over the mud and the engraved letters small, but this just adds to the challenge and makes obtaining a successful record all the sweeter.

I remove my hand from its woolly cocoon long enough to start a new page in my notebook. I enter the date, Feb 2nd, time (13.30) and the approximate number of birds present. I’m joined on the beach by my colleague Chris and together we scan the flock. Concentration and cold render us mute. A glance to our left and right confirms we are the only people on the shore. The only sounds come from the birds. Their feet and bills patter through the mud with a wet slapping sound as they make frequent dashes and probes for food. They communicate to each other with calls that resemble a Jackdaw and a clucking hen. The birds are close; I feel that we are going to get a sighting. Sure enough a flash of yellow ring is spotted and, after a few minutes following the bird through the telescope, we both agree on the full code: Yellow (ELY) – Red.

Back from the beach and firmly ensconced in a warm office I waited with a steaming cup of coffee for the feeling to come back to my fingers, toes, nose etc. Once re-heated I composed the email to the Norwegian Knot Project leader with details of our sighting. Jim Wilson is a member of the International Wader Study Group executive committee and a committed wader-ologist and has been running this project for the past 7 years.

Observers on the Dee have contributed records of his birds for several winters and so he had decided to pay us a visit in November 2011 to see where some of his birds were ending up. Richard Smith and I showed him around the best Knot sites during his week long stay and over dinner on his final night came an invite to join him in Norway to take part in fieldwork during an expedition to Porsanger in May 2012. There was no way I was going to turn down such an opportunity and I accepted there and then, any other arrangements would have to be juggled! The rest of last winter was spent looking for his birds culminating in the sighting I described above.

Eventually, May rolled around and Chris and I packed our bags and, leaving the Dee basking in a mini heatwave, we prepared for two weeks several hundred miles inside the Arctic Circle, around 70 north.

                              Porsanger Fjord, northern Norway Matt Thomas

We were staying in a small village called Veidnes at the mouth of Lille Porsanger. The accommodation could only be described as authentic. A traditional Lap tent with a carpet of reindeer skin and fitted with a wood burning stove for warmth was our home for a stunning fortnight. During our stay we saw no darkness, the sun nearly setting, but not quite. Around us Sea Eagles patrolled sheer cliffs, lemmings scuttled across the tundra, reindeer herds grazed scanty vegetation and Snow Buntings – rare winter visitors on our patch- were garden birds!

On the fjord the Knot had arrived a couple of days before us, zooming up from their staging post in the Wadden Sea on the tail of a southerly gale.  I am well used to seeing big numbers of Knot, often up to 25,000. But I was not prepared for the sight and sound of 50,000 summer plumaged birds. They looked like a totally different species. Gone were the soft grey tones of winter, replaced by smouldering ember-red breeding colours, just stunning. Once we had got over the spectacle of numbers, striking appearances and set up our camp we got down to work. We headed straight out on the mudflats looking for marked birds and investigating places to try and catch and ring some more.

The scenery was breathtaking. Huge expanses of inter-tidal mud were flanked by snow clad craggy mountains. During our stay Spring arrived. Rising temperatures melted snow that swelled rivers and triggered rumbling avalanches. This left vast patches of black scree slopes exposed making the hills look like huge Fresian cows sleeping next to the clear blue waters of the fjord.

               Knot in Porsanger Fjord, looking north towards its breeding grounds Matt Thomas

Over our two week expedition we were able to contribute much more data to the Norwegian Knot Project. Our top priority was to find and record ringed birds and while collecting this data I had an amazing encounter with an old acquaintance.

The heading in the notebook was May 25th. Time was recorded as 13.30, and about 500 birds on the rocky shore. I was looking through the telescope at the flock when I spotted a ringed Knot. It was hard to follow; it kept disappearing behind a large boulder that was particularly heavily bearded with yellow-brown slimy seaweed. Like the other birds on the beach it was hoovering up shellfish and worms at a rapid rate. Eventually it briefly moved into clear view, I got a reasonable look at it and was able to read the first letter of the code on the yellow ring. E. More following with the scope and I read the second letter. L. Finally it wandered into the open and I could complete the code. Y. I looked again, double and triple checking. The code was definitely ELY. This rang a big bell in my head and I started to flick back through my notebook until I reached the page headed Feb 2nd. There it was, scrawled in scratchy black biro ink, Yellow (ELY) – Red. Confirmation that I was looking at the same bird Chris and I had seen on the Dee!

112 days after I first saw it, there I was sharing a beach with this bird again, crunching over the same shingle, squelching through the same mud. I was aware there was a chance that I would see a bird in Norway that I had seen on my local patch but I hadn’t seriously entertained the idea. It was an odd set of feelings, seeing this bird again, a cocktail of surprise, wonder, excitement, respect and sense of mild concern. I found myself feeling strangely connected to this bird, I wanted it to survive the rest of its perilous journey to the high Arctic and to successfully rear chicks.

Our meeting obviously made more of an impression on me than on ELY. As I got all misty eyed it continued to fuel up for the remainder of its migration, coming across an unusually meaty worm in the grainy grey gloop and gobbling it up before flying off with the rest of its flock to a bay further down the coast. Leaving emotion aside I moved on to the next site to look for more ringed birds, however, I did spend the rest of the day grinning from ear to ear and was quick to tell the story of our reunion to anyone who’d listen.

This sentimental anecdote aside, what are we learning about the Knots of Porsanger fjord from this colour ringing project? Below I summarise some of the preliminary sightings kindly sent to me by Jim who has crunched the numbers and analysed the data since our return south.

A link with Iceland is emerging. Some of the birds ringed in Norway appear in following years in Iceland but not, so far, in Norway again. This “switching” is puzzling, has only recently been discovered and will require further investigation. During our trip 9 sightings came in of Norwegian ringed birds in Iceland. Four of these had not been sighted in Iceland in previous years. No birds ringed in Iceland, no Porsanger marked birds which have been sighted in Iceland and no Dutch ringed birds which have a history from Iceland were seen by us in Norway. So at the moment the data suggests that the switch to Iceland is a one way movement – they do not come back. However the Porsanger population seems stable. Odd!

During our expedition we made 431 flag readings of Porsanger marked birds involving 255 individuals. We also made a lot of density counts of flagged birds (how many flagged birds in the flock on view). From previous ringing between 2006-2009 we sighted 28% of birds assumed to be still alive (working on a 15% rate of mortality). As it was known that Porsanger birds are spread throughout the Norwegian population and that an unknown number switch to staging posts in Iceland it was a good effort to see so many. Hopefully it should now be possible to determine some mortality estimates as over 50% of birds marked in Porsanger fjord have been seen there in later years.

                                  Colour Ringed Knot at Porsanger Matt Thomas

Up until and including 20th May there were estimated 40,000 Knots in the Lille Porsanger/Veidnes complex. However, on each evening tide birds were seen leaving in small flocks towards the east in typical migration mode on a bearing of about 80. Later in the trip 5,000 were found in Varangerfjord 150 km to the east.

Varanger was almost certainly the destination of these birds. 25 individual Porsanger ringed birds were seen in Varanger between 23rd and 26th May. 11 of the 25 (44%) had been sighted in Lille Porsanger between 10th and 19th May and 2 Dutch ringed birds were also spotted there which had originally been sighted on 19th May 2012 in Lille Porsanger. This nicely demonstrates the within year link between these 2 sites.

                                            Knots in Porsanger Fjord Matt Thomas

When birds fly to Varanger they move 150 km to the east – as they then fly west again at the end of May towards Greenland they are adding 300 km to their migration distance.

To compliment the observations of the Knots several transects to sample food availability were made at various muddy locations up and down the fjord. Paired samples were taken with a 5 cm diameter core to a depth of 4-5 cm at 100m intervals. They were sifted through a 2mm sieve to find the creatures the Knot were feeding on.

1-3mm shells are probably lost in sieving, and with the proviso that the growth rate of Baltic Tellin was unknown to us, a preliminary look at the data suggests that either there has been no Tellin population growth in Lille Porsanger in recent years, or more likely, the area has been grazed out over the last 3-4 years by the thousands of Knots which have been seen there. Surprisingly, there were many large Tellins at Lille Porsanger, which suggests that there was a period in the past without grazing. Indeed during 2005-2007 fewer Knots were found there and the large shell size does suggest that there must have been a period with few Knots and this nicely ties in with observations made during that time. Conversely the absence of large shells at other locations suggests a period of heavy grazing. This information suggests that the birds make some movements in relation to food availability, but there may be other factors at play here too including…

…Peregrines! In Porsanger Peregrines are migrants that arrive at about the same time or just after the Knots. Knots are probably their main, perhaps only, food source in the last two weeks of May. A migration ready Knot would be an ideal energy filled meal for a raptor about to start its breeding cycle. During our trip we saw frequent Peregrine attacks and sometimes birds were suddenly alarmed, probably by a Peregrine which we did not see. Birds reacted strongly to Peregrines and were seen to move several kilometres after an attack. It is possible that Peregrines are driving the distribution of Knots around the fjord in conjunction with the food supply.

More analysis of the distribution of Peregrines and Knots over previous years is required. As there are now fewer Peregrines nesting on the west side of Porsanger fjord and they are more common on the east, the impression is that the Peregrines are following the Knots and establish their nesting sites where they find the big flocks in the spring. However, all this is complicated by changing quantity in food resources. From 2004-2008 many Knots were on the West side of Porsanger fjord which has since been deserted. It will be interesting to see what areas the Knots use in 2013.

So there we are, for now my story is complete, but as the last line of the previous paragraph suggests there is more work to do and more places to see.
We have answered some questions but we have discovered more that need our thought, research and discussion. Further expeditions may be required. Is there anything more exciting than that?

In the meantime we can all help. Please look for colour ringed birds when watching the waders on the estuary. Each sighting is vital, the information gained can help to conserve these wonderful birds and protect the special wetland habitats that they need and we enjoy. Email records to: richard@deeestuary.co.uk

Matt Thomas
http://deebirder.blogspot.com

                                            
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August Bird News


                     Marsh Harrier over Burton Marsh, August 11th David Wilson.
An excellent month's birdwatching! There were two cracking rarities - an Aquatic Warbler in the reed bed at Red Rocks on the 19th and 20th was only the second record for the Dee Estuary area, the first being at the same site in 1976. The other was a Balearic Shearwater seen off Hilbre on the 15th, although they are reported fairly regularly in the southern Irish Sea it is an excellent record for Liverpool Bay. A Pectoral Sandpiper at Burton Mere Wetlands was another good rarity at the end of the month, they are more or less annual in Cheshire and Wirral.

Without actually checking I would guess we've had more Marsh Harrier sightings this month than we've ever had before! It's reckoned we've had six here - two wing tagged juveniles, 1 male, 1 moulting female, 1 juvenile not wing tagged, 1 female. The wing tag of one of the juveniles has been read and it was one of a brood of three tagged this year in East Anglia, a remarkable and unexpected north-west movement.

After the massive fall of Willow Warblers on Hilbre in early May we didn't expect to see another one this year, but that's exactly what we got with an estimated 700 coming through on the 14th, they managed to ring a remarkable 165 of them at the Bird Observatory.

                                One of 700 Willow Warblers on Hilbre, Aug 14th
                      Matt Thomas, see 'From the Muddy Banks of the Dee' Blog.  
As expected wader numbers built up rapidly during the month after the breeding season finished, max counts as follows: 4,900 Dunlin at West Kirby on the 17th with 4,500 at Hoylake on the 19th; 1,000 Ringed Plover at both Hoylake on the 19th and Hilbre on the 22nd; 6,800 Redshank at Heswall on the 20th; 1,210 Black-tailed Godwits at  Burton Mere Wetlands on the 26th, 1,500 Sanderling at Hoylake on the 31st - all these are excellent counts for August. 10 Spotted Redshanks at  Burton Mere Wetlands on the 25th was the highest count for this relatively scarce wader. 4,500 Shelduck at Heswall on the 20th was a very high count for August, presumably they have just finished their annual moult.  Four Garganeys were at  Burton Mere Wetlands, see photo below.


                     Garganey at Burton Mere Wetlands, Aug 21st David King.
Terns dominated the beaches and sea. After the demise of the Shotton Common Tern Colony three years ago numbers of this species really dropped, but last year we saw a return to larger numbers post-breeding and this year we've had very big counts with 820 on the 6th and up to 1,000 on the 19th, both at Hoylake. Many, if not all, will be from the colony at Seaforth and, judging from the number of juveniles, they seem to have had a reasonably successful breeding season. It was noticeable all summer that the birds were flying west along north Wirral to feed off Red Rocks and Hilbre, far more so than the previous three years. Sandwich Tern numbers were also high with around 1,000 at Hoylake on the 19th and similar numbers at Hilbre and West Kirby. Up to 200 Arctic Terns were recorded with good numbers around all month, this is a very high number for this species and greeted with scepticism by some - all I can say is that they were identified and counted by several different people, at least four of which are well known and respected local birders. Little Terns were also seen with over 70 at Both West Kirby and Hoylake, I've not heard the final count of fledglings at Gronant but know they've had problems with Kestrels, nevertheless quite a few were reared successfully.  Unexpectedly 11 Black Terns turned up at HilbreRed Rocks and Hoylake with several of them still in full breeding plumage, they were present from the 13th to 19th - a lovely sight.

Apart from the terns there were no large movements of sea birds, but up to five Arctic Skuas were around for most of the month with one or two Great Skuas passing through.


                            Great Skua off north Wirral, Aug 23rd   Richard Steel..
Richard Smith.
 
Many thanks go to Jeremy Bradshaw, Malcolm Sergeant, Paul Brady, Steve Hinde, Kenny Dummigan, Greg Harker, Steve Williams, Charles Farnell, Mike Hart, Andy Thomas, Ashley Cohen, Ray Eades, Bruce Atherton, Chris Butterworth, Jane Turner, Peter Haslem, Dave Wild, Matt Thomas, Paul Mason, Steve Seal, Tim Baldock, Paul Earley, Stave Hand, Mark Evans, John Blore, David Wilson, Jeff Cohen, Brian Lingard, Roy Lowry, David King, Eichard Steel, David Small, Dave Harrington, David Haigh, Richard May, David Galatas, Dave Edwards, Charles Canning, Austin Morley, Andy Evans, Ian Fleming, Glyn Roberts, David Leeming, Karen Leeming, Mark Gibson, Nigel Jaratt, James Smith, Tony Cumberlidge, Roger Jacobs, Eddie Williams, Ian Emmitt, Graham Thompson, Ian Cotterell, Mathew Fry, Brian Roberts, the Dee Estuary Wardens and the Hilbre Bird Observatory for their sightings during August. All sightings are gratefully received.
 

What to expect in September

North Wirral, Hilbre and Point of Ayr are nationally renowned for Leach's Petrels, especially in September. Whether we see any, and how many, is very dependent on the wind. Ideally we need several days of North-westerly gales during the middle two weeks of the month, and that should result in well over 100 of them each day the gale lasts. 2011 wasn't bad as far as Leach's Petrels are concerned but 2010 was a classic year and to read about this and the weather conditions at the time see the October 2010 Newsletter.

Strong winds can also bring in plenty of other good birds and expect to see Arctic Skuas in double figures, Great, Pomarine and Long-tailed Skuas, maybe a Sooty Shearwater or two, Sabine's Gulls and Grey Phalaropes.

Last year was a classic for Curlew Sandpipers with large numbers particularly at Hoylake and IMF/Burton Mere Wetlands - see November 2011 Newsletter - it would be fantastic to get the same again this year!

September is often an excellent month for rarities, and there can be such goodies as marsh terns, Wryneck, rare Warblers and rare Waders. Other than that expect to see good numbers of Greenshank and Spotted Redshanks, plus Hen Harriers and Short-eared Owls returning to the marshes.
 
                                        Leach's Petrel off North Wirral Steve  Round.

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Forthcoming Events

September Highest Spring Tides (Liverpool)

Also see Tides page.
17th September, 12.34hrs (BST), 9.7m.
18th September, 13.13hrs (BST), 9.8m.
19th September, 13.54hrs (BST), 9.7m.

Forthcoming Events

Organised by the Wirral Ranger Service , Flintshire Countryside Service and/or the RSPB:
All these events and walks have bird interest, even those not advertised specifically for birdwatching. No need to book for these events unless specified - please check below.
Also see 2012 Events Diary.

LiverBird Watching and Nature Discovery Crusies 2012 - Click here for details.

Saturday 1st September, 6pm - 8pm, An Evening with Egrets at Burton Mere Wetlands RSPB.
Price: 2 RSPB members, 5 non-members.
Booking essential.
The Dee Estuary is home to the largest number of little egrets in the entire North of England and believe it or not they all roost in one small group of trees near to Burton Mere Wetlands.
So come along for a short talk on the trials and tribulations of little egrets in the UK before a gentle stroll down to the Marsh Covert Hide to watch as hundreds of egrets come "home" to roost.
This truly is one of the best wildlife spectacles at this time of year in the north.
Places are limited so book in advance to avoid disappointment.
Cost includes a cuppa and biscuits.

Saturday 8th September,  Hilbre Low Tide Birdwatch, 8:00am start to 1:30pm latest.
Join the Rangers, the RSPB and staff from the Hilbre Bird Observatory on this low tide birdwatching event on Hilbre Island.
Booking essential
.  Phone (0151) 648 4371.

Saturday 22nd September and Sunday 23rd September. Happy Birthday at Burton Mere Wetlands.
10am - 4pm
Price: Free
Help us celebrate Burton Mere Wetlands' 1st Birthday weekend as there will be lots going on including family activities, guided walks, prize raffle and of course there will be delicious homemade cake! The wardens are hosting free guided walks about how and why the reserve was developed, the walks will start at the reception building and last approx 1 hour.
And best of all in the spirit of celebration its free entry for everyone.

Saturday 29th September, The Big Seawatch, Hilbre.
Join the Rangers, staff from the RSPB, Hilbre Bird Observatory and the Sea Watch Foundation for a day on Hilbre looking for seabirds, waders and cetaceans that inhabit our wonderful coast.  We will be staying on Hilbre during high tide, giving us the best chance to see them with experts on hand!  There is a small charge of 1.50 for this event which includes tea/coffee.
Booking Essential.  Please ring (0151) 648 4371.

Tuesday 2nd October.  “The Thurstaston Circle”.
10am start at the Visitor Centre, Thurstaston.
A guided birdwatch along Thurstaston Shore, across Heswall Fields and back to the Visitor Centre via the Wirral Way.
We will be following the rising tide along Thurstatson Shore looking at the birds being pushed towards the marshes at Heswall.
Warm waterproofs and good walking boots/Wellingtons recommended. Bring some binoculars if possible.
(0151) 648 4371 for more info.

Saturday 6th October and
Sunday 7th October. Skydancers at Parkgate - 12 noon until dusk.
Skydancer is an exciting new four-year project aimed at raising awareness and promoting the conservation of hen harriers in the north of England.
The Dee Estuary is a vital wintering ground for these amazing birds and is the best place to see them from October through to March.
Most people have never seen a hen harrier, but once seen it is rarely forgotten. This bird is a beautiful, agile hunter, and its aerobatic sky dances are among the most awesome spectacles in nature.
Unfortunately, with only a handful of pairs still breeding successfully in England, the hen harrier is currently a species on the brink.
Come along to Parkgate to find out more about the hen harrier story and what you can do to help save hen harriers before it's too late!
Look for the RSPB Love Nature marquee along the main promenade at Parkgate where friendly staff and volunteers will be with telescopes and binoculars plus family activities, free information and more: http://www.rspb.org.uk/skydancer/
Directions: The "Donkey Stand" opposite Nicholls Ice-cream shop on The Parade (B5135), Parkgate, Cheshire.