By 30 May, the team had recorded 3,776 colour-banded or flagged birds, the majority of which are from NW Australia. They have precisely 1,000 Broome/80-mile Beach colour-band observations, of 321 individual combinations dominated by 273 Red Knots. The total of 876 individually identifiable birds includes birds banded in Australia (Victoria, Queensland, South Australia), Russia (Chukotka & Kamchatka), New Zealand, Thailand, Japan, and Hong Kong, among others.
The team also reports on the state of land reclamation projects (with a port development threatening to take 54 km2 of mudflats). Another issue is cordgrass Spartina encroaching the mudflats, They say: “it has expanded rapidly along the Nanpu mudflats and is now present at all our survey sites. The good news, however, is that this year the problem has been acknowledged by the local government, and a team of workers has been busy clearing out the dead grass to allow better access to living stems”.
By the time they published the final report on 6 June, they had accumulated 4,122 flag and colour-band observations, the highest total since 2015. This includes birds from 21 banding regions and they have seen flags or bands on 14 species. Their total of 1,097 NW Australia colour-band observations is the second highest total in 9 years of visits to the site!
Jeroen Reneerkens of the University of Groningen studies breeding Sanderlings, for the first time in 2003 and since 2007 annually. He works from the Danish Zackenberg Research Station (74°28’N 20°34’W) in NE Greenland that was established in 1996, and is the research base for various experts monitoring the biotic and abiotic environment of NE Greenland.
Jeroen reports about his remarkable 2018 field season:
I study how rising temperatures may affect the reproductive success of Sanderlings in Zackenberg, NE Greenland. Due to a disproportionate degree of climate warming in the Arctic, shorebirds that migrate to the Arctic to breed are strongly suspected to be negatively affected by ongoing climate change. Niels Martin Schmidt and his team have indeed established that the summer temperatures in Zackenberg have steadily increased during the last decades.
The expected consequence of the warming Arctic summers are a mismatch in timing between arthropods (think insects and spiders), and their shorebird predators. Indeed, the emergence of crawly creatures in the pitfall traps in Zackenberg has advanced in the last two decades, but I learned that Sanderlings in Zackenberg did not adjust the timing of their incubation. Puzzling.
So to further study the ecological interactions between Sanderlings and their prey (and the predators of Sanderling eggs such as Arctic foxes), this summer of 2018 I visited Zackenberg for the 13th time. It turned out to be an exceptional season…
Snow, very much snow!
Sanderlings and other Arctic shorebirds start laying eggs when the snow melts, which usually happens in the first weeks after their arrival, around late May or early June. Shorebirds are so-called income breeders, which means that females produce their eggs from locally acquired food. Their food appears only as soon as the tundra soil becomes snow-free.
Snow melts quicker with higher summer temperatures but it’s not that straight forward because climate models also predict that the amount of winter precipitation (i.e. snow fall) will increase. If that is true, more snow may counteract the effects of warming summers on the timing of emerging of arthropods.
Before I migrated north to follow the Sanderlings, my Danish colleagues who were in Zackenberg since early June had already reported that there was a lot of snow on the tundra and warned me that I should prepare myself for a late breeding season. On satellite images of mid-June 2018 the tundra surface was close to 100% covered in snow, and not only in Zackenberg but in the entire Northeast Greenland national park. After a delay of two days due to fog in Zackenberg in which the small chartered planes cannot land, I arrived in Zackenberg on 14 June.
In the last two weeks of June usually most Sanderling are on their nest while some late breeders, or birds whose first clutches fell victim to egg predators, can be found singing or foraging in pairs while the females gather insects to produce eggs. But not this year…
The amount of snow was so extensive, that the majority of the shorebirds in the Zackenberg valley had flocked together in the snow-free area around the field station. Very lean birds were walking between the wooden buildings in the research station and could be approached up to a few meters, probably because they were not willing to spend their last energy and the much needed time to forage on escaping from human researchers.
Catching shorebirds within the research station
It was clear that no shorebirds were going to nest within the next few weeks, if at all this summer. This exceptional situation gave me the opportunity to document the effects of the large amounts of snow on the behavior of shorebirds and their condition.
Usually, food left-overs from the station’s kitchen are discarded via a hose into the nearby Zackenberg river, such that its smell will not attract Polar Bears to the station. However, the river also only started running on 20 June, which is 16 days later than the average date in 1998-2017; a new record. The researchers were forced to get rid of the grinded food remains onto the tundra close to the station. Luckily, it did not attract Polar Bears, but it did attract a flock of several tens of shorebirds, mainly Sanderlings, Turnstones and Red Knots.
This gave me and my Danish colleague Jannik Hansen (Aarhus University) the possibility to catch birds and assess their body condition. We managed to catch 31 Sanderlings, 23 Turnstones and 12 Red Knots. Several birds were recaptured 1-3 times within a few days.
All individuals were in poor condition. Sanderlings weighed on average 44 grams (range: 33.6-54.6 grams). In comparison, Sanderlings in winter in the Netherlands weigh between 50-55 grams and incubating Sanderlings weigh on average 57 grams. It is good to realize that the incubating females have already produced a four-egg clutch weighing ca. 48 grams before they start incubation!
The locally colour-ringed birds were resighted daily near the sewage outlet and between the station buildings near snow edges. I daily woke up and went to bed with sightings of colour-ringed birds just a few meters from my bedroom window. The food waste close to the station was probably a unique opportunity for shorebirds, as there is only one village and a handful of stations in entire NE Greenland. The body masses of recaptured Sanderlings showed that they could maintain or even increase their body mass. But not all of them.
I found two dead Sanderlings near the station who seemed to have starved to death. One of them weighed 34 grams at first capture and only 32.6 grams when recaptured a few days later. It was found without head, weighing 26 grams. The other, un-ringed but intact, Sanderling weighed 31.8 grams which indicates that many of the Sanderlings were in very poor condition, indeed.
I was delighted with the recapture of a Sanderling which I ringed in Zackenberg as a 7–day old chick on 14 July 2012 and was now almost 6 years old. Luckily, with a weight of 54 grams, she was among the few birds in a good condition.
The sewage near the station did not only attract hungry shorebirds, but also served as a feeding tray for the local Gyrfalcons. Jannik and I almost daily observed one of these large white falcons hunting shorebirds, often flying only a few meters over our heads! Although we did not witness a successful attack, prey remains and plucked feathers in the vicinity of the station indicated that either the Gyrfalcon or possibly Arctic foxes were preying on the starving shorebirds.
A non-breeding year?
During the two-week period that I was in Zackenberg, I did not hear a single singing Sanderling and only a few times I heard a singing Red Knot or Dunlin. I observed two Sanderling pairs, which however seemed to have broken up, or at least could not be found again, during the following days.
Also surprisingly few Sanderlings that were locally colour-ringed were observed. Because Sanderlings are very site faithful to their breeding territories, and given that the snow conditions were similar in the whole range of northeast Greenland, I think that the majority of Sanderlings never arrived in Zackenberg but stayed in more southerly regions with better feeding possibilities.
In recent years, Sanderling hatch dates in Zackenberg ranged between 27 June and 30 July (average 12 July). With an incubation duration of 22 days and four days to lay the clutch of four eggs, this implies that Sanderlings usually start laying around 16 June and at the very latest at 4 July. Given that on 27 June all of the Sanderling habitat in the Zackenberg valley was still covered under at least a meter of snow, it is very unlikely that Sanderlings and other shorebirds will breed this year in Zackenberg, or even entire Northeast Greenland.
Request to report the proportion of juvenile Sanderlings within flocks
What are the consequences of a non-breeding season for the Sanderling population? This will depend on the scale at which the snow cover has affected Sanderling reproduction. The Sanderling breeding area is larger than northeast Greenland only, and it is possible that outside the area affected by snow, Sanderling reproduction will be good this year.
I ask for your help to document the effect of snow conditions on Sanderling reproduction and to score the number of juvenile Sanderlings within flocks at your local beaches. I prefer you to repeatedly observe and score the percentage of juvenile birds in the same area between August and November, following a standardised protocol. You can find more information in the manual which can be downloaded below. Download the Sanderling Ageing Manual here.
Klaassen, M., Lindström, Å., Meltofte, H. & Piersma, T. (2001) Arctic waders are not capital breeders. Nature, 413, 794.
Reneerkens, J., Schmidt, N.M., Gilg, O., Hansen, J., Hansen, L.H., Moreau, J. & Piersma, T. (2016) Effects of food abundance and early clutch predation on reproductive timing in a high Arctic shorebird exposed to advancements in arthropod abundance. Ecology and Evolution, 6, 7375–7386.
Reneerkens, J., van Veelen, P., van der Velde, M., Luttikhuizen, P. & Piersma, T. (2014) Within-population variation in mating system and parental care patterns in the sanderling (Calidris alba) in northeast Greenland. The Auk: Ornithological Advances, 131, 235–247.
Schmidt, N.M., Mosbacher, J.B., Nielsen, P.S., Rasmussen, C., Høye, T.T. & Roslin, T. (2016) An ecological function in crisis? The temporal overlap between plant flowering and pollinator function shrinks as the Arctic warms. Ecography, 39, 1250–1252.
Eva Kok (Royal NIOZ and PhD student at the University of Groningen) reports about satellite-tagging Red Knots in two major wintering areas of the East Asian–Australasian Flyway in NW Australia: Roebuck Bay and Eighty Mile Beach. In February 2018, she worked there together with team leader Chris Hassell (GNF Australia) and PhD student Drew Bingrun Zhu, and was supported by the AWSG, Ying Chi Chan and Lee Tibbitts.
“It has been more than two months since the NWA expedition 2018. More than ever it was an expedition full of challenges, mainly due the arrival of cyclone Kelvin. After a lot of rain, and waiting, we were eventually successful in catching and equipping 2 gram satellite PTTs on Red Knots using the full body harness. In the past two months we have been excitedly following the movements of these birds.
We caught the Red Knots well in advance of the expected migration to the breeding grounds to give them time to adjust to wearing the tiny tracker and gain sufficient amounts of energy stores to take on the long-distance flight north. According to expectation, the first few weeks were characterized by short-distance movements on the mudflats between foraging grounds and high tide roosts.
The first movements happened in the first week of April when two birds, who were caught on Eighty Mile Beach (80MB) before the cyclone hit us, moved up to Broome and mingled with the tagged birds that we caught later in Broome. This is a regular movement, and the birds settled on the mudflats of Broome where Chris and Kerry saw the knots growing fat (see picture below).
On 25 April our wait was finally rewarded when the first bird, caught at Roebuck Bay on 18 March, finally decided to cross the Timor Sea to fly to Borneo. For a moment we thought this was the signal for migration to start, but in the meantime the other birds did not show any sign of migratory movement, and the days passed by.
Eventually the real wave of departure started almost three weeks later! Then six other Red Knots exchanged the mudflats of Broome for the mudflats in Indonesia and the Philippines. On 22 May 2018 already two Red Knots had reached China and we can’t wait for them to show us where they will go next to breed.”
Video by Drew Bingrun: Eva Kok and Chris Hassell releasing satellite-tagged Red Knots.
The field work in NW Australia in February 2018 that made it possible for us to successfully deploy Red Knots with solar-panelled satellite-transmitters was funded by the MAVA foundation. We want to thank the members of the expedition of the Australasian Wader Studies Group (AWSG) for their help and support in the field.
This week the team reports a lot of exciting information about bird numbers. We will not give it all away here. Besides the shorebird work, the birding this week has been fantastic. On top of the good numbers of regular migrants, they found a few unusual and/or out of range species. Read for yourself in the PDF at GFN website.
The GFN team is in Bohai Bay, China, to study Red Knots and Great Knots on northward migration. Chris Hassell, Adrian Boyle and Matt Slaymaker post regular updates on the Australian Global Flyway Network website. Here is the third of this season.
In short, the team reports that it has been a busy week in Bohai with early mornings, lots of people and loads of birds. They did a shorebird count of the whole study site coastline and nearby salt ponds, and of course spent long hours re-sighting. This time they also report on an invasion of human visitors to the coast:
Drew, Leiming, Tong and Hebo, together with a large team of volunteers, joined to work on their various projects, and of course Theunis was there!
Also Katherine Leung from Hong Kong joined for a week’s scanning. Scott Weidensaul from the USA spent a few days with the team and Terry Townshend dropped by for a weekend.
Hank and Wendy Paulson spent a morning birding on the sea wall and surrounding area. The Paulson Institute has been influential in helping to attain Nature Reserve status for Nanpu mudflats and the birds behaved impeccably for their visit!
And there is a competition! With a prize for the 1st mail to Chris Hassell with the correct subspecies of a Mai Po – Hong Kong re-sighting (photo in report).
A report from David Chan (volunteer for Coastal China Survey) on 12/5/2018:
It was a sunny day after a few days of rain and disappointment. Not many Great Knots were seen on the mudflats at Lianyungang for the past few days. Hebo brought us to this last site hoping to find more knots there, especially a Great Knot carrying a solar-paneled satellite transmitter (also called a PTT – Platform Terminal Transmitter -, or simply “sat-tag”). From its location data we knew it was there. Fortunately, we counted a few thousand Great Knots foraging near shellfish farms. So besides continuing the foraging study of Great Knots by filming them, the next task, obviously, was to find our sat-tagged friend, the bird carrying the satellite transmitter, who led us all the way to this site.
Throughout the whole day, we scanned different flocks of Great Knots hoping to find it. The light turned softer at the golden hour and sunset was near but we did not want to give up on scanning. In a flock of resting knots, two Great Knots with colour-rings caught our attention. Looking closely, we saw an antenna attached on one of them. Immediately we knew that this was the bird!
This sat-tagged Great Knot at Lianyungang was coded 7YRYB. 7YRYB was banded with a yellow flag (Roebuck Bay, Australia) and four colour-rings (Yellow-Red-Yellow-Blue, so YRYB). 7YRYB was a she (identified by DNA techniques) banded 29/09/2016 at Richards Point in Roebuck Bay and fitted with a satellite tag. Yet, her migration journey was not ordinary. After banding, she flew two thousand km to Papua New Guinea and stayed there for the whole breeding season of 2017 (see Chris Hassell’s blog on 19/04/2018).
Her northward migration this year started on April 10 with a four thousand km direct flight to Taiwan. Surprisingly, one local birder Mr Lin Jer An was able to photograph her on April 16th and took a video the next day (see Chris Hassell’s blog). It is always delightful to see photos of birds carrying a PTT tag doing fine. She left Taiwan around April 20th and arrived at Jiangsu Province on the next day. After a few days, she flew north to Lianyungang and we saw it on May 8th.
It was a joyful moment watching the seemingly fattening 7YRYB feeding at Lianyungang. Direct observation and foraging videos help us understand the birds’ condition and behaviour (you can watch the video above). Unfortunately, the building of a big port nearby might affect this section of mudflat and the thousands of shorebirds that stop here during their migration. An all too familiar issue in coastal China but some good news is also out now (more information in Wader Study, also in Mandarin, and on mongabay.com).
Her migration journey was amazing, from Australia to Papua New Guinea, and from Papua New Guinea to China. She revealed some interesting movements and brought people caring and studying shorebirds along the flyways together, from Australia, Alaska, Taiwan and China. Migratory birds like 7YRYB connect scientists, conservationists and bird-lovers. We hope the stories of 7YRYB may raise awareness about their survival and the threats they are facing.
We wish her all the best on the coming journey and breeding season. Godspeed.
12/05/2018 (World Migratory Bird Day 2018)
[David works with Ginny (Ying Chi Chan) from Royal NIOZ Netherlands Institute for Sea Research and University of Groningen, The Netherlands].
Please note this article is derived from raw data and has had no checking or statistical analysis applied to the PTT data.
News from Bingrun Zhu (Drew) – College of Life Sciences, Beijing Normal University (BNU) and University of Groningen (RuG).
Drew studies the melanuroides population of Black-tailed Godwits. He does field work in Bohai Bay and Inner Mongolia in China, but also in Thailand and Australia (read more here). Currently he is in Bohai Bay. He reports:
“I’m very happy to share this exciting news: one of the female Black-tailed Godwits (H35) that I caught in the spring of 2017 in Hangu, Tianjin (Bohai Bay, China) is now heading north again!
After a cozy winter time in Samut Sakhon of Thailand, she left her wintering grounds on 11 April 2018. Then she flew directly north-east to near Poyang Lake, Nanchang Province of China, and disappeared for quite some days. She showed up again on 26 April at Dongying, Shandong Province (instead of meeting me at the North shore of Bohai Bay). She started the trip northward again on 7 May, and now 5 days later she has already reached Russian soil. She is outside a city named Borzya, Zabaykalsky Krai Province, only 700km east of Lake Baikal.
I hope she’ll have a successful breeding season out there, and will stay away from hunters…
The GFN team is in Bohai Bay, China, to study Red Knots and Great Knots on northward migration. Chris Hassell, Adrian Boyle and Matt Slaymaker post regular updates on the Australian Global Flyway Network website. Here is the second of this season. The team reports:
Scanning come rain or shine…
We have had a bit of everything this week, Thunder and lightning, rain, wind and sun. Good days, bad days and completely useless days when the tide simply failed to come in, remaining 100’s of meters offshore. This happens occasionally, out of sync with the days either side, and ruins our scanning plans! Perhaps it is due to weather, atmospheric or environmental conditions elsewhere in Bohai Bay or the Yellow Sea?
Generally, numbers of birds on the mudflats are increasing daily. Great Knots, an early migrant, are already here in good numbers; however, Red Knot were a little later than usual. The last few days have seen a significant increase in numbers but there are still plenty of ‘Broome birds’ yet to get here.
Our second count of the season, scheduled for the next couple of days, will hopefully provide a more accurate measure of what is here. While many shorebirds are still some way to the south, others have started to leave with a small flock Eastern Curlew seen migrating north over town on the 25th April…..The full report can be found at the website Global Flyway Network Australia.
The GFN team is in Bohai Bay, China, to study Red Knots and Great Knots on northward migration. Chris Hassell, Adrian Boyle and Matt Slaymaker post regular updates on the Australian Global Flyway Network website. Here is the first of this season. The team reports:
Here we go again… another year and another season in the Yellow Sea!
This year your early-season correspondents are the Bohai stalwart Adrian Boyle, here for his 10th year in a row, and Matt Slaymaker, a former regular returning after a three-year break spent experimenting with a full-time ‘normal’ job.
We both arrived on the 10th and were out in the field the following day to find a good spread of Great Knots across the usual study area with smaller numbers of Red Knot, Bar-tailed Godwit, Grey Plover and other species scattered through the intertidal areas and nearby saltpans……. The full report can be found at the website Global Flyway Network Australia.
And an extra story! 7YRYB Great (K)not following the rules.
A short story about a Great Knot by Chris Hassell: PDF and embedded video are here.
Exciting times! Great Knots and Bar-tailed Godwits have started to leave their non-breeding grounds in Northwest Australia to migrate north to their Asian staging areas. Six of the Bar-tailed Godwits (two from Broome, four from 80 Mile Beach) are in the air, with one already at Tiaozini, Jiangsu, China!
Lee Tibbitts was the first to remotely see the migration starting. On 6 April she messaged after looking in the satellite data: “Great Knot 833 was flying along Taiwan about 10 hours ago. Maybe you will see an influx of birds soon”.
Indeed on April 9 Ginny Chan reported that Great Knot 833 has just arrived at Jinjiang, Fujian, China. Ginny Chan and team are currently at the China coast for field work, and they have actually seen this satellite-tagged bird at Jinjiang! It’s in a group of 79 Great Knots and looking good. According to Chris Hassell at its last three resights in Roebuck Bay, Broome, it had been scored as 75% breeding plumage already! Chris saw it last at Richard’s Point in Roebuck Bay on 29 March 2018, and now a mere ten day later it is at Jinjiang.
Ginny further reports there are other Northwest Australia Great Knots in the flock. She photographed the yellow flagged 1XA (the AWSG scheme) and satellite tagged Great Knot 833 who is colour-ringed with 6LYBY (the GFN scheme).
Great Knot 833 in Jinjiang. Photo: Ginny Chan
Flagged bird in Jinjiang. Photo: Ginny Chan
A bitter taste
Of course, we are excited that migration has started, but this year it has a bitter taste. To prepare for their long flight to Arctic breeding areas up to 70,000–80,000 Great Knots (of the total population of 290,000) refuel at the most northern staging site in the Yellow Sea, Yalu Jiang National Nature reserve in Liaoning, China. But something is wrong there. David Melville (research scientist involved with China shorebirds for a few decades) says: “Word is spreading that there is no food at Yalu Jiang and that they would be better off staying at Broome!?”. What if Great Knot 833 goes there?
The most important food source for the thousands of shorebirds staging in this reserve, small clams, has crashed. This means that Great Knots, after a long-distance flight in which they will lose nearly half their body weight, will find insufficient food at this major northern Yellow Sea stopover. This strongly reduced food supply means there is going to be a lot of competition and likely a die-off.
You may know that IUCN lists Great Knot as ‘Endangered’, while the Australian Government consider it to be ‘Critically Endangered’. In other words, Great Knots have a hard time already, and losing more birds is a risk we cannot take.