Bohai Bay Fieldwork Journal 2015 from Global Flyway Network

Updates:

Update 1 | Update 2 | Update 3 | Update 4 – Red Knot Edition | Update 5

Updates will be added below as we receive them, please visit GFN website to find the original updates:

Bohai Bay

Update 1

 

GFN Northward Migration Season in Bohai Bay 2015

Well it’s that time of the year again. Shorebirds are migrating from their wintering areas and up to the breeding grounds in northern China and Russia. Of course it’s beneficial for the birds to stop off and refuel on their arduous journey and that’s what the Luannan Coast on Bohai Bay is famous for, the important feeding grounds for migratory shorebirds here. Once again the Global Flyway Network will be studying the shorebirds as they pass through this critically important site. GFN are here for their 7th consecutive year. As always the team arrived early into the second week of April whilst the shorebird numbers are still low. Although the team members will increase in number later into the season it currently consists of Adrian Boyle a Bohai veteran from Broome Western Australia and Bob Loos a GFN team member from the Netherlands. This season started a bit slow with Shorebird numbers. Normally when we first arrive the mud flats have hundreds of Dunlin, Eurasian Curlews and Grey Plovers but very few were to be found. The first 3 days were spent checking all the usual haunts without any luck. Then on the 15th they arrived ‘en masse’ and soon we had hundreds of Great Knots to scan. It still took several more days for the Red Knots to arrive and by the 18th of April the count of 200 from the 12th had risen to 6,000. We have conducted a full count off all our sites for 6 species and the totals comprise of Great Knot 6,636 Red Knot 7,031 Bar-tailed Godwit 1,105 Black-tailed Godwit 14,040 Grey Plover 2,867 and Eurasian Curlew 1,686. Several of these species are still increasing daily and we expect larger counts over the next few weeks. The Black-tailed Godwit and Eurasian Curlew counts are the largest we have ever had during our visits. However it is difficult to look too positively on this, it is unlikely to be an increase in the populations of these birds given all the information we have on them. It is more likely they are from other sites that have been lost to development.

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Some of the thousands of Black-tailed Godwits counted over the past week. © Bob Loos
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The first colour banded bird for the season. However it flew away without revealing its full combination! © A Boyle

One of the obvious changes we have seen since last season is there are now lots of markers with flags on them. These are everywhere in the saltpans and cover the mudflats every hundred meters or so. We have since learnt that this is the first stage of more oil exploration and there are ‘sensors’ across the mudflat. On top of that a large ship and several ‘zodiacs’ are setting off explosions in the water! The sensors record the data and indicate where the oil might be. However to get the data from the sensor you need a super loud boat to run across the mudflats to collect it! This, of course, disturbs the birds when we are trying to count and scan. The good news is that we have heard the exploration work will be over in a few days. If they find oil the news will not be so good for the birds.

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One of the 5 super noisy boats. © A Boyle

The road that we take from our apartment in Nanpu to the mudflats every day is a little worse for wear, to say the least. It takes us approximately one hour depending on traffic and how deep the puddles are. So it was with great excitement that we looked out the window on our first day to see a new road being built. It is quite large and will probably be a 4 lane highway by the time we visit next season and cut down our travelling time. Yipppeeee!!!!!! Oh hang on where is the road going? Yep true to form, as we have learnt over the years if you find a good spot for wildlife don’t expect it to be there for very long. The highway is going to pass straight through 2 of the best salt ponds for birds that we have ever seen in our study site (or anywhere we have worked around the world actually!) When the conditions are right as on May 16 2013 when we recorded 95,833 birds in one pond and on May 29 of the same year we had 34,200 Red Knot feeding in the neighbouring pond. They have started to build a wall through the middle of the pond to put the road on it but we are not sure yet if they will totally drain it, build on the pond adjacent to the road or how the new road will affect water circulation and depth. I guess time will tell. Will there be other suitable ponds for the birds to use?

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The road being built in the salt ponds © Bob Loos

Despite all this the area remains brilliant for birds (but for how long can they persist?) So far we have seen 118 species in 10 days. Some highlights were 4 endangered Oriental White Stork including 1 on a nest, Brown-eared Bulbul and Woodcock at the park being a first for us and 9 Black-necked Grebes at Zuidong. We will send more news in the coming days. 

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Grey-faced Buzzard at Tree Lane © A Boyle
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Pied Wheatear at Zuidong © Bob loos
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Common Redshank on the mudflats © A Boyle

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Update 2

 

GFN Northward Migration Season on the Luannan Coast, Bohai Bay 2015 Update number 2

 

A day in the life of a GFN Red Knot researcher.

So what’s it actually like to be doing what we do in China? Apart from seeing some of the doom and gloom that we post in the journals it may look like we just drink beer and eat dumplings. Of course this is not the case so here is a break down. What we do each day is governed by three things 1; the tide (the tide chart isn’t always too reliable), 2; what the birds are doing (the birds are not always too reliable) 3; the weather (yes, correct, the weather isn’t ——–). This past week has been great for tides. The light is best in the morning and from around 10.30 it starts to get very hazy as the brighter sunlight seems to worsen the effect of the air pollution. In the afternoon unless’ we are out on the mudflats, scanning can be pretty difficult as we are generally looking into the sun. So with tides like the recent series with medium high tides peaking early in the morning. We start off from our apartment at around 4AM. Leaving at this time of the morning means that we can’t get our breakfast dumplings on the way (we don’t like that!). It’s still dark outside and the journey to our main site takes around 45min so you can sometimes get a little bit of extra sleep if you’re lucky as the road is very bumpy. Sometimes the journey takes longer due to all the trucks that are building the new road.

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One of the reasons we can be slowed down on the way to work. The amount of rock carried in each of these trucks in incredible. We see large rocks that have fallen off the trucks all the time on the road and this is the 2nd truck we have seen tipped over this week. © A Boyle

We get to our site around 5AM and get into position behind a small wall of concrete and peer over to scan the shorebirds as the tide pushes them closer and closer. It’s not until 5.20 that there is just enough light to start reading bands. Depending on the time and height of the tide we can be here for several hours until the tide gets high enough to push the birds off to their salt pond roost sites (or a truck beeps it horn at us for no obvious reason and scares the birds away!) As the birds head to the roosts they fly over the top of us and into many large salt ponds and sleep a lot during the high tide period. This is a very different experience for us and the Broome birds. Roebuck Bay’s birds get a lot of disturbance at their roosts from raptors and people. Here the feeding areas are under threat from reclamation but the roosts are relatively undisturbed by either raptors or people.

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Bob Loos scanning from the sea wall. However thick fog cancelled play early this day and you can see it rolling in on the mudflats behind. © A Boyle

Once the birds have gone to roost it’s time for a quick cup of tea and then into the salt ponds to continue scanning. At this time of the year and day it can be a little cold and many of the birds are all fluffed up keeping warm whilst they sleep and therefore they are hiding the treasures we are seeking, flags and colourbands, under their feathers. Sometimes they reveal them as they walk around the roost site but it’s still a great chance to collect data. Here we do many scans of the flocks to work out the percentages of the 2 different subspecies of the Red Knots we are researching. Combining this with our counts we can get an estimate of just how many of each subspecies are using this site at a particular time.

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This is a typical view of roosting knots and Dunlin. Can you spot the 2 subspecies of Red knots present in this flock? © A Boyle

On average we spend 3 hours in these ponds and then it’s time to walk out back up onto the road and get into position for when the birds fly out of the ponds and back onto the mud exposed by the falling tide. This doesn’t always work as we would like! Often the knots choose to sleep well after the tide has dropped enough for the mud to be exposed and when they finally arrive back on the mud they are too far away to scan successfully for bands and flags. As the tide goes out it moves on an angle to the road so we are able (up to a point) follow the birds along as the mud that is exposed giving us close enough views to read more of the many different flags and bands that have been placed on the shorebirds in banding studies throughout the EAAF. So far we have recorded 1033 birds marked with flags and or colourbands on 11 species from 23 sites in our flyway. As we mentioned above the light does start to work against us and eventually it is unproductive to continue so it’s then time to head off for the rest of the day’s activities but you’ll have to wait for another update to read about those.

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Spotted Redshank. One of the sexier shorebirds. © A Boyle
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Saunders Gull with green flag U7 banded near Panjin China. © A Boyle
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Male Yellow-bellied Tit. One of the more common non-shorebirds that we occasionally find a moment to enjoy. © A Boyle

Original post:    

Update 3

 

GFN Northward Migration Season on the Luannan Coast, Bohai Bay 2015 Update number 3

 

People are Great

Time fly’s when you are having fun and it’s hard to believe that some of the team has been here scanning for over a month. The Red Knots have increased in number greatly since the last update and we have recently counted just over 47,500 of them as well as 16,700 Great Knots. The numbers of Great Knots using the Luannan Coast are a lot higher than in previous seasons. This could be an effect of the lack of food currently at Yalu Jiang National Nature Reserve 500kms to the ENE of here, on the China/North Korea border. Yalu Jiang has historically been a stronghold for Great Knots on northward migration. The news we are getting from shorebird colleagues is that numbers are much lower there this year, presumably due to the lack of suitable prey species for Great Knots. We have had some rain on a few nights recently and this makes for good birding as the bad weather brings birds down to land until the weather clears for them to continue their migrations. As a result our species list for this season has jumped up to 181. The Nanpu sea wall has had hundreds of birds of numerous species in the reeds and low bushes. We walk many kilometres along the sea wall on most days to scan the knots and we occasionally sneak a look at the odd non-shorebird! With the large numbers of knots arriving it means more flagged birds. To date we have seen at total of 1,989 sightings on 12 different species from 26 different banding sites. In regards to the birds marked in Broome and 80 Mile Beach NWA we have recorded 313 colourbands records and 461 flag records. This is total sightings not individual birds. Usually by now in previous year’s updates we would have been writing about the large numbers of birds feeding in the salt ponds. Unfortunately this year the water levels are too high to give optimum feeding conditions for the shorebirds. We have been told that the water levels are high this year ‘to compensate for the loss of salt pond area due to other salt ponds being sold for development or, as mentioned in an earlier update, roads being built through them. So instead of the tens of thousands of birds in the ponds we are currently limited to hundreds. As you may have read in last years Update number 6 another one of the many problems this area and the Yellow Sea mudflats in general face is the inexorable spread of introduced Smooth Cordgrass (Spartina alterniflora) taking over the mudflats. It grows thickly and renders mudflats completely unsuitable (in fact not even accessible) to shorebirds. The control trial we conducted last year has gone very well. All the small patches that were sprayed have died. Some of the larger ones have had some regrowth where presumably the spray didn’t penetrate through the previous year’s dead leaves. There are still a few large patches that we didn’t spray last season that need tackling. We had planned to spray early into the season but as the plant had not started to grow when we arrived we will try again in the coming weeks. During a recent exploration of other small areas of mudflat further west of our main study site we saw a small bay that had a large area of Spartina on it. The thought that it was too cold here in the winter for Spartina to grow well and be a threat to the mudflat habitat was, unfortunately, dispelled by what we saw there. This is too big an area for us to attempt to control and we just plan to try and keep our survey area as free from Spartina as is possible. There is also an area of Spartina in Zuidong and a week ago we drove past and found some locals digging it up. Some of us got excited thinking that maybe the locals are trying to help eradicate this invasive species. However other more cynical ones (Chris) was horrified that it might be being moved to colonise other mudflat areas to stabilise areas for reclamation. It was neither. It seems it was being dug up to be planted in a wetland reserve nearby! Sometimes you just need a brick wall to bang your head against.

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The small bay near Tianjin rapidly being covered with Spartina. © A Boyle
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The Spartina ready to be taken to a nearby wetland to start its path of destruction © Bob Loos
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Lee and Bob G scanning on the mud at Nanpu © A Boyle

In the past we have written about the shell fish harvesters working in our study area. They are a small group of people approximately 8 that work during the middle of the tide out on the mudflats collecting shellfish. They do this by using a generator-driven harvesting machine that collects mud and then a high-powered jet of water washes the mud away leaving the edible shellfish behind. It’s a very profitable industry for the local operators and would be in to the future if it is being managed sustainably (this we do now know). The harvest is loaded on to boats that are anchored close to the working parties and brought in to the seawall. Here the shellfish are unloaded onto a large truck and taken to Beijing to be sold in restaurants. Recently we watched some boats being unloaded. The first three bags from each boat are weighed and then all the bags are put on to the truck. One bag weighs 30kg and we did some simple arithmetic and came up with a truck load carrying 32.4 tonnes of shellfish! It’s amazing just how productive the mudflat can be for both the local economy and the migrant birds. The shellfish workers appear to be out every day and as shellfish don’t keep well we presume this is what is taken out of the mud every 1-2 days during the shellfish ‘season’ which we think is spring and early summer. We want to try and talk to the local shell fishers as good healthy shorebird habitat, without industrial complexes built on it, is good for shorebirds and the local economy.

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The question is; is it sustainable? © A Boyle
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© Bob Loos

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A beautiful male Yellow-rumped Flycatcher © A Boyle
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Reed Parrotbill. Common on a reclaimed but currently unused and overgrown area just inland from the Nanpu sea wall, where we scan the Red Knots in the mornings © A Boyle

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A rarity for us here; Little Owl on the Nanpu Seawall © Bob Loos
PEOPLE

Most of you reading these updates will be well aware that long periods of field work don’t happen by chance. They happen because of lots of planning, lots of planning and lots of planning (previous experience is a great help too) and skill and effort once the fieldwork begins. This effort is both voluntary and paid. So funding is critical to long-term studies and fieldwork.

It is difficult to know where to start with the long list of regular and visiting shorebird biologists this year.

But let’s start at the top

Theunis Piersma who is the ‘leader’ of GFN was with us again, just for a few days, on the Luannan Coast. He was in China for longer than the few days for meetings and to catch up with his various PhD students. Theunis is the main fund-raiser for all of the GFN studies in Australia (including my position) and the EAAF. This commitment to a flyway that is not his ‘own’ is typical of Theunis, he has a world view of shorebirds and ecology. It also highlights the immense importance and issues in the EAAF that someone with such standing in the shorebird world should put so much effort in to the EAAF. He would like to stay with us for longer scanning through massive flocks of Red Knots but his other beloved shorebird, the Black-tailed Godwit is breeding in the meadows around his home in the Netherlands and he has a large long-term study on that species underway (of course he does!)

Now we go to ‘no particular order’.

Lee Tibbitts is a shorebird biologist with the United States Geological Survey’s Alaska Shorebird centre and works in close conjunction with GFN, in particularly on satellite telemetry studies with Black and Bar-tailed Godwits, Red and Great knot. We have had the pleasure of working with her 4 times in Roebuck Bay since our first meeting in 2008. This was Lee’s first trip to China to see the spectacle of the birds but the rampant industrialisation of their mudflat habitat was an eye-opener for her (as it is for us all on encountering it firsthand for the first time).

Bob Gill is recently retired from the same office as Lee and is ‘busier than ever’! Bob has done pretty much everything in shorebird work particularly on the Alaskan breeding grounds.

It was Bob’s second visit to join GFN on the Luannan Coast and he was keen to see the changes since 2011. The destruction of the mudflats wasn’t that much greater but over previously reclaimed flats and salt ponds now stood factories, high-rise apartment blocks (mostly empty) and massive highways. It was interesting to look at it through Bob’s eyes from a 4-year time period, as we see it every year and it seems less dramatic that way! Bob has also been with GFN in Roebuck Bay for the Bar-tailed Godwit satellite telemetry studies in 2008. Bob is a thoroughly sensible bloke and can chat to Chris about sport and not just shorebirds!

Tony Habraken is something of a legend in New Zealand for his scanning prowess and dedication. The conditions here didn’t prove as enjoyable as the crisp clean NZ air he usually works in. However from out of the smog he sighted many and varied colourbands and flags to add to our ever-growing data set. Tony has plenty of experience of working in these conditions having been in the Yellow Sea at Yalu Jiang, South Korea and was also a team member of the NZ shorebird ecologists that were invited to North Korea in 2009.

Professor Zhang Zhengwang, who is the supervisor of Leiming (current PhD) and was for Yang Hong Yan (Nicky). He joined us just for a day but he and Theunis had many productive talks about present and future studies as well as about the students that Beijing Normal and Groningen Universities are sharing. Prof Zhang always helps hugely with transport to get many and various people between Beijing and Nanpu Industrial City our ‘home base’. Our programme here would not be possible without our association with BNU.

Leiming is our new ‘go to guy’. This used to be Nicky’s role. They both do and did it with a smile on their faces but we do sometimes wonder if they perhaps tear some of their hair out in private! As we do not speak any Chinese other ‘thank you’ and ‘I don’t understand’ we rely totally on Leiming to help us with many things on a daily basis. We really cannot emphasise enough how helpful he is. And while he is fielding our phone calls and sorting out this and that for us he is doing his PhD field work, catching birds, counting birds, collecting mud samples, collecting water samples and then sorting those samples etc.! He is one busy young man. His main study is on shorebird use of the salt pond habitat with the Curlew Sandpiper his main study species. This bird had decreased in numbers alarmingly in the EAAF and is currently being assessed by the Australian Government for ‘upgrading’ of its threatened status.

Kate is a Polish Graduate and is Leiming’s ‘right-hand woman’ and helps him with everything except sorting out our phone calls! Kate studied introduced mammals (Racoon Dog and American Mink in Poland for her under graduate degree and Red-backed Shrike for her Master’s Degree. She is now learning the joys (?) of shorebird research in the Yellow Sea.

And last but certainly not least we have a new ‘full-time scanner’ for this season as Matt Slaymaker could not be with us this year because he got a proper job. For those of you who know Matt- the wandering bird ringer-Slaymaker you may be as surprised as Ady and I were! Bob Loos is the GFN accountant and rather conveniently is an experienced scanner who has worked on shorebird studies extensively in The Netherlands, Mauritania, Norway and Iceland. It didn’t take long for Bob to get in to the swing of things here. Shorebird studies the world over are determined by the tide and if that means getting up at 3:30 or 4AM because the tide is suitable, well that’s what you do. The smoggy conditions are a bit different to what Bob is used to but like all of us this somewhat unpleasant part of being here is countered by some incredible views of shorebirds in full breeding plumage, sometimes very close. And standing on the seawall as the tide recedes and 50,000+ shorebirds fly from their roost sites and swoop down on to the mud is a site to behold. Bob is also a keen birder in general and lots of new birds keep popping up in front of his binoculars so that also helps with the early starts the pollution an having to cope with my and Ady’s ‘humour’!

So that is the people who have so far made up our Bohai Team 2015 and our shorebird studying friends. In a few days we get more volunteers and students, we might give them a mention in another update.

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Left to right; Tony, Bob G, Ady, Lee, Chris, Theunis, Bob L
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Leiming and Kate wait for Curlew Sandpipers to show up © Bob Loos

Original post:  

Update 4 – Red Knot Edition

Catch up and History of Red Knots on the Luannan Coast, Bohai Bay

Back in late 2005, Professor Theunis Piersma, leader of the Global Flyway Network (GFN), proposed setting up a long-term monitoring project in North West Australia to complement the already established studies being conducted by the Australian Wader Studies Group (AWSG). Initially the chosen study species was Red Knots, Great Knots and Bar-tailed Godwits. Black-tailed Godwits were added in 2008. The main study site was Roebuck Bay, Broome, Western Australia. The main funding source was Birdlife-Netherlands.

The project involved catching these species and attaching colourband combinations to enable individual recognition. The second and critical part (sometimes underestimated in other studies!) was to conduct intensive re-sighting effort over many years, to build up a picture of how these three species were faring through annual survival analysis. Chris Hassell was employed full-time to conduct the research, with Birdlife–Netherlands funding. The same colour marking method used by Professor Piersma on the East Atlantic Flyway, to allow survival on a different flyway to be compared with here and the East Asian-Australasian Flyway.

Things started off well, with the first birds banded in December 2005 and regular re-sighting scans underway in Roebuck Bay. Fairly soon it became clear we weren’t getting as many records of Red Knots as we were of Great Knots and Bar-tailed Godwits. The latter two species are highly site faithful, but not so Red Knots, who only use Roebuck Bay temporarily. Lots of Red Knot that are caught in Roebuck Bay as first year birds, move on during their first year to other sites ranging from ‘just down the coast’ 165km south-west to Eighty Mile Beach of Broome or all the way to New Zealand 5,400km away. This was not entirely new information, we knew about this from recoveries of metal bands and flag sightings, but with individually marked birds we were ‘fine-tuning’ our knowledge. This posed an issue for analysis of the data. If a considerable proportion of the marked population were not site faithful, even mathematics couldn’t come up with accurate annual survival estimates.

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© Ian Southy

There is a good chance of marked birds being seen at Eighty Mile Beach as both GFN and AWSG work there and scan the flocks, and in New Zealand there are some skilled and dedicated scanners. But that still leaves the rest of the EAAF and particularly during the migration season even with some dedicated scanners in China, the enormous Yellow Sea coastline gets little attention. After phone calls with Mark Barter and others and reading a few papers, we knew we needed to be in northern Bohai Bay in May to see if ‘our’ birds were there on northward migration. PhD student Yang Hong Yan was studying on the Luannan Coast and Chris visited her study area for seven days in 2007. Despite the brevity of the visit, seeing a flock of 9,900 Red Knots loafing on the mudflats just off the seawall with the two subspecies side by side was enough to convince Chris that GFN needed to spend more time here. Soon a plan was hatched to visit this site yearly when the knots were present in large numbers to look for colour banded birds. That way it wasn’t so critical if we missed birds during the non-breeding season in areas with little or no resighting work, as we could see them when they pass through Bohai Bay in China.

So how many colourbands do we record whilst working in Bohai? Each year we seem to be getting more and more sightings. This is not surprising as we have been putting more and more combinations on. For example during the 2014 season we made 920 Broome colourband sightings which comprised 345 individuals. In addition to this are all the other flags we record and in 2014 we saw in total 5018 banded/flagged birds. With still over two weeks to go it looks like we are on track to record more than that this season.

In the East Asian-Australasian Flyway there are two subspecies of Red Knot spending the non-breeding season and migrate within it (a third breed in the EAAF but to our knowledge migrate exclusively to the America’s). In non-breeding plumage the Red Knot subspecies are inseparable, however in breeding plumage they can be separated reliably in most cases. We assess the subspecies on all the banded and flagged Red Knot we see, not just the GFN colour banded birds, and this increases our knowledge of where these two subspecies spend the non-breeding season and the areas they pass through to get to the breeding grounds based on their banding locations.

We also do daily scans of around 1,000 individuals randomly amongst the flocks, to assess subspecies percentages. This informs us of the timing of the migration of each subspecies through Bohai Bay, and when multiplied into our counts, this gives us an idea of the two populations of both subspecies using this area.

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A large flock of knots flying over the Nanpu mudflat. © Adrian Boyle

The rogersi subspecies arrives in large numbers first and are the most numerous of the two subspecies during April and into mid-May. Then the piersmai start to arrive and around the same time the rogersi subspecies start to head further north to their breeding grounds and so the piersmai become the dominant proportions of the flocks. This pattern is shown well in the graph below from 2014.

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A nice dark piersmai. / A much paler rogersi.

What numbers of knots are we talking about that are using Bohai Bay?

Well if you ask us its pretty much all of our flyways population. The highest count for our survey site was in May 2011 with a total of 66,500 knots. Like any large site with big tidal movements and here in Bohai Bay the huge area of salt ponds, getting accurate counts is challenging. The 66,500 is 50% of the EAAF flyway population during one count! More birds were probably present in the salt ponds. The total number of Red Knot using the area is obviously much higher when the turnover of birds migrating through is taken in to account. Our biggest count this season is 47,500, but that was earlier in the season and before the piersmai subspecies had arrived in peak numbers.

Why are the knots gathered in such large numbers on the Luannan Coast?

There are two main reasons;

Large scale habitat destruction elsewhere in the EAAF, particularly on the Yellow Sea coast line. Historically the Luannan Coast may not have been the only major feeding site for Red Knots, but due to mudflat destruction on a massive scale in the past decade, the area available for shorebirds to feed has been greatly reduced. Luckily this super-productive piece of mudflat has remained intact and still supports impressive numbers of Red Knots (and many other species).

Red Knots are very specialised feeders when they are on mudflats. Red Knots feed on very small bivalves and the Luannan Coast has a huge volume of suitable sized prey for them. This particular bivalve is Potamocorbula laevis (Pots). Mud samples taken at other mudflats where Red Knots don’t occur reveal that this small bivalve is absent, or in low numbers. One of the reasons why this particular bivalve is so common on the Luannan Coast may be due to one of the bivalves main predators, a large shrimp species that has been over-fished and now ‘Pots’ have been able to increase their population.

Why do we only visit on northward migration?

Unfortunately very little is known of Red Knot southward migration in our flyway. At the time of writing we still do not know of a site that holds large numbers of Red Knots on southward migration.

Do they stop over on their way back to their wintering grounds or fly directly back?

Geolocator studies in Russia, New Zealand and Broome indicate they do stop over, in or close to Bohai Bay. However several visits here by local birdwatchers, have yet to turn up any large numbers during that time period.

Could this mystery southward staging area be under threat also? We assume so. Finding this site and assessing its threats is one of GFN’s main priorities.

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Some of the small bivalves that the Red Knots eat when in Bohai. © Jan van de Kam
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A rogersi feeding in the salt ponds of the Luannan Coast, Bohai Bay. © Adrian Boyle

Abdominal Profiles

In the absence of body mass data from captured birds, it is possible to score the abdominal profile (AP) of birds in the field from telescope observations. We record abdominal profile on all birds when we get a suitable view. A side-on view of the bird is needed for an accurate assessment. A factor the observer has to take into account is if the bird is ‘fluffed-up’ due to cold weather. This can mislead the observer into thinking the bird is ‘fatter’ than it really is. This can certainly be a problem, but the experienced observers of GFN are aware of this and so all observers are scoring under the same criteria. The scores range from 1-skinny to 5-obese. A bird scored as 1 looks unhealthy and a bird scored as 5 can hardly walk, it waddles!

It would seem that both subspecies and most individuals are arriving at our Luannan Coast study site in good condition whilst almost no birds are arriving in very poor condition (AP 1). This probably means that they are stopping or staging between their Australian and New Zealand non-breeding sites. We do know that some birds stop in Hong Kong and southern China from resighting records. This is however one piece of the Red Knot migration question that we are still attempting to answer with various methods; GFN and the Australian Wader Studies Group (AWSG) currently have 42 geolocators deployed with the hope that we will recover some of these birds in future capture events to gain further insight into the migration strategy of Red Knot from NWA.

The graph below shows the increase in AP, over time, for the two subspecies of Red Knot in 2014. The dip in the last week of sightings is probably because most of the ‘fat’ birds have left leaving a lighter cohort behind.

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A rogersi subspecies of Red Knot with an abdominal profile score of 5. This individual is surely ready to head further north any day now. © Adrian Boyle

Not only is Bohai Bay important for Broome’s Red Knots but practically all the Red Knots in our flyway. We have recorded banded Red Knots from 19 banding localities at Bohai Bay. So if this small remaining piece of mudflat is destroyed it will affect Red Knots throughout the flyway.

Below is a representative map showing most of the Red Knot banding locations seen in Bohai. Some have been left out due to them not being able to be seen under all the others!

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It’s been a busy 10 days since the last update.

We have now recorded 3152 flags and band sightings from 28 banding regions on 12 different species. This includes a total of 699 Broome colourband sightings.

Total bird species recorded 203

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Update 5

GREAT SCANNING AT BEIPU

Our study site on the Luannan Coast is split in to a number of different areas for our recording purposes.

Mostly we write about ‘Nanpu’ (north Village). This stretch of mud and seawall gets most of our attention. Why? Simple, it gets most of the birds, probably as it has had the least reclamation work done on it and has been able to keep its ecological character more intact than Zuidong and Beipu (south Village). However, between May 21 and May 24 this season it was ‘going off’ (Australian saying meaning it was very good)! Over those five mornings of scanning, we read 328 individually marked Red Knot from NWA and of those 89 of those were ‘new’ – we had not recorded them before during this season. Great data and well worth those 3am alarms (have we mentioned those before)?!

The mudflats at Beipu are 4.5km long and approximately 4km wide at the lowest tide. The flats have undergone many changes since our first visit in 2009. When we first surveyed Beipu, we could only drive to the end of the seawall from the Nanpu / Beipu creek and the road was a ‘dead-end’. Now with the reclamation of more mudflat area, there is a road that allows us to continue on and round to the area we call ‘North Beipu’. The scanning we do at this site is on shrimp ponds where birds roost and feed. This site only seems to have birds there from about mid-May onwards. There is possibly no suitable food before then.

During our field work in 2009 and 2010 we were regularly scanning at Beipu with thousands, or tens of thousands of Red Knots frequenting the site. However, soon after our field work season finished in 2010, work started. This was the ‘usual’ method of many large industrial mud-pumping ships, pumping mud out of the mudflats and over the seawall in to the adjacent salt ponds. So it damages two shorebird habitats in the one process. The mud is extracted to a depth of 15m. This brings up anaerobic sediments. The heavy sediments settle and remain in the ponds while the finer sediment and water run back out of sluice gates placed in the seawall for this purpose. As the fine black water and sediments run back over the mudflats we think they smother it and cause and the benthos to ‘suffocate’. This is what we saw happen at our southern-most study site of Zuidong. Luckily for the birds (and our studies!) there was a commercial dispute and the destruction stopped after a year and only about 25% of the Beipu stretch of mudflats had some pumping done on it. However, the run-off of the fine anaerobic sediments covered a far greater area and in 2011, 2012 and 2013 shorebirds were only found in very small numbers there. In 2014 occasionally we saw medium sized flocks there, but we did very little scanning at the site.

This year on May 20 this all changed rather dramatically. On May 20 we looked across onto the mudflats of Beipu from the Nanpu / Beipu Creek (as we always do but never really expect to see much) but there in the distance we saw thousands of Red Knots feeding on the mud.

Will they be there the next day? Would they turn up as soon as the tide recedes? Do we put all three scanners in this area and risk missing out on Nanpu (which we know will have birds)? We have learnt over the years at this study site that when something is just right for birds, in terms of tide, wind and light conditions on the coast, or water depth and wind in the ponds, it rarely lasts so it was decided to risk all three scanners. A 3am alarm start so we would arrive just as the mud was exposed on an out- going tide. At the seawall we split up and positioned ourselves where we thought the birds would land. The wind was light and the sun was just lifting through the smog as the mud became exposed. Then came the birds and the gamble had paid off. The birds landed right in front of all three of the chosen positions and we ‘cleaned up’. It was our biggest day for the season with no less than 84 different Broome colour-banded Red Knots being recorded that morning.

It has taken a few years for the Beipu mudflat to be suitable for birds again, but this season shows it can really be great. It would seem mudflat habitat can cope with small amounts of change and rehabilitate itself to a degree. However, it was only luck that saw the development at Beipu stop and if it had gone under concrete we wouldn’t have this story to tell. However, as with all our sites there is still no protection for this area and each year we visit, we are unsure if this habitat will exist. Further north, adjacent to Beipu a 2sq km area of mudflat is currently being destroyed for aquaculture ponds.

As regular readers know our main target when we are here is to collect sightings of colour-banded birds from NWA, but we don’t allow any flag or band to go past our telescopes un-recorded. It is too good an opportunity to collect data for other banding studies throughout the EAAF.

This was our best ever season for records from the GFN colour marking project in NWA, total sightings (1,221) and individuals (437), remarkable when these birds are caught and marked 6,400km away. One of the Red Knots we sighted is a minimum of 26 years old (26+). It was first caught and given a metal band in Roebuck Bay, Broome on October 10,1992 when it was already a minimum age of 3 (3+). It was then re-trapped on September 16, 2007, then a minimum age of 18 (18+) and given the colour-bands combination 1RLLB. It has been seen twice this season here on the Nanpu mudflats. This is the oldest Red Knot known to us in Australia.

And in addition to the colour-bands we have recorded 3,264 flags and bands for other projects!

It is now time for us to leave the Luannan Coast for another year. We hope to be back again next year (if funding can be found) to follow the fate of the enormous numbers of migratory shorebirds that flow through here each spring season.

NOT SHOREBIRDS

Every day during our field work season we keep a daily log of all birds seen and it is great to see the data on this building up. Most birds we record are migrants like the Red Knots and they are heading north to breed. This season we have recorded 208 species during our two month visit. Despite this being our seventh year we still are seeing species we have not recorded before. Take the White-shouldered Starling for example. This is a species that breeds in Vietnam south and south-east China and spends the winter in Taiwan and south-east Asia, but this individual had strayed well over 1,000km north to our survey site in Nanpu and is a first record for the Hebei province.

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White-shouldered Starling © Adrian Boyle

Some of the other interesting sightings over the past few weeks have been Indian Cuckoo, Middendorff’s Grasshopper-Warbler, Azure-winged Magpie and several sightings of the endangered Yellow-breasted Buntings. Moreover, on the mudflats we have seen Chinese Egret feeding amongst the thousands of shorebirds.

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Thanks to everyone who has assisted us this season. And particular thanks to Leiming who is a constant help to us day in and day out, thanks Leiming.

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Global Flyway Network website

Global Flyway Network Bohai Report 2014