Ginny Chan of the Royal Netherlands Institute of Sea Research reports:
On 18 October 2017, David Chan, an intern at Royal NIOZ, presented a poster in the HKU Science Undergraduate Research Poster Presentation, at The University of Hong Kong. The poster is titled Site fidelity of shorebirds fuelling in China, and focuses on two species of shorebirds, Bar-tailed Godwits and Great Knots, along the China coast.
Using banded individuals with colour rings and engraved flags, we showed that Bar-tailed Godwit individuals are more loyal to the same stopover site than individual Great Knots. For more details, please check the poster on ResearchGate.
This analysis is an important first step to understand how shorebirds are affected by habitat loss in their staging sites. In a previous paper in Wader Study, we demonstrated that the main habitats of Bar-tailed Godwits in the south Yellow Sea coast in Jiangsu Province, China, are planned to be reclaimed. As Bar-tailed Godwits are shown to be loyal to their staging site, it is unlikely that individuals can redistribute to other staging sites. This further strengthen our argument that ‘loss of habitats equals loss of birds’.
Theunis Piersma, Ying-Chi Chan, Tong Mu, Chris J. Hassell, David S. Melville, He-Bo Peng, Zhijun Ma, Zhengwang Zhang, David S. Wilcove (2017). Loss of habitat leads to loss of birds: reflections on the Jiangsu, China, coastal development plans. Wader Study 124: 93-98. doi: 10.18194/ws.00077
The Global Flyway Network team, consisting of Chris Hassell, Adrian Boyle, Bob Loos, and Theunis Piersma report the findings from the 2017 field work. Chris: “Unfortunately but not unexpectedly, results were similar to those of 2016: the Red Knot that spend the non-breeding season in north west Australia (NWA) arrived at the Luannan Coast in much lower numbers than in previous years and earlier in the season.”
The Luannan coast of Bohai Bay is vital for Red Knots
In summary the GNF team consisting of Chris Hassell, Adrian Boyle, Bob Loos, and Theunis Piersma recorded 2,765 marked shorebirds from throughout the East Asian-Australasian Flyway (EAAF) compared to 3,554 during the 2016 field work season. This year 295 birds were individually recognizable from the Global Flyway Network (GFN) colour-banding project in NWA. This is exactly the same number as in 2016. This was of course dominated by Red Knot Calidris canutus with 269 individuals identified, then Great Knot Calidris tenuirostris with 22 and Bar-tailed Godwit Limosa lapponica with 4. As in previous years, this reflects the vital importance of the area for Red Knots from NWA.
Reduction in use of alternative feeding habitat in commercial ponds
Besides the inter-tidal area, the importance of the vast area of commercial ponds adjacent the mudflats is documented by GFN and by Beijing Normal University (BNU) students in previous years In 2017 the use of ponds by shorebirds was less than in previous years. The number of birds utilising the ponds was reasonably high during April but much lower during May than in previous years. The team expected big numbers of Red Knot to use the ponds during mid to late May, as was seen in previous years, excluding 2016. This, however, did not eventuate. Red-necked Stints and Curlew Sandpipers were not present in big numbers either. This was probably due to the generally high water levels in the ponds giving fewer foraging opportunities.
Some species were (much) more common than usual
On 2 April large numbers of Black-tailed Godwits Limosa limosa (a minimum 17,100!) were using the Hangu site. This single count is higher than any we have recorded in previous years and represents 11% of the current EAAF population estimate. Also the highest count of Asian Dowitcher Limnodromus semipalmatus was recorded – 1,754 on 8 May also at Hangu. On May 7 a count of 40,000 Dunlin Calidris alpina was the biggest count of this species over all our study years.
Conservation recommendations – speed of reclamation of mudflats
The continuing pressures on the intertidal area are obvious with the development of industrial and housing areas adjacent to and on reclaimed mudflats. In our study area the direct destruction of the intertidal habitat has slowed in the last five years. The building projects that are taking place in former pond habitat and mudflat areas reclaimed in recent years appear to have slowed. There were many fewer trucks, cranes, plant machinery and workers in the area. We assume this slowdown is due to the general downturn of the wider Chinese economy. However, a six-lane highway has been constructed part way along our study site, bridges are in place and a new road through the ponds is under construction. It would only take an upturn in the world, Chinese or local economies to see renewed expansion and loss of mudflats in this critically important area. Currently multi-billion yuan projects are in the planning stages for development within the Luannan Coast area.
The ponds in the salt works area host all the migrant birds at high tide when the mudflats are inundated by the sea, making the area a critical component of the Luannan Coast Shorebird Site. These ponds should be included in any conservation initiatives. They are also contributors to the local economy and jobs.
GFN plans for coming years
The Global Flyway Network aims to continue to conduct research activities and follow up analysis to document the fates of four shorebird species (Bar and Black-tailed Godwit, and Red and Great Knot) at their non-breeding sites in NWA and throughout the flyway, with an emphasis on the Luannan Coast, Bohai Bay. This will depend on continued financial support. From this work we will be able to assess the effects of human induced habitat change through statistical analysis.
GFN will continue to support conservation efforts with in-depth analyses of the data collected at Bohai Bay in conjunction with Department of Conservation-New Zealand, World Wide Fund for Nature (WWF)-China, and Wetlands International-China. Dr Tamar Lok, a postdoctoral researcher from the University of Groningen, Post-doc Dr Hong- Yan Yang at Beijing Forestry University and PhD student Ying-Chi Chan, will continue to analyse GFN data under the co-supervision of Professor Theunis Piersma. All work will be in close cooperation with Beijing Normal University and Fudan University.
The full report titled “RED KNOT NORTHWARD MIGRATION THROUGH BOHAI BAY, CHINA, FIELD TRIP REPORT APRIL – JUNE 2017” can be downloaded here.
Professor Theunis Piersma, of the University of Groningen and of the NIOZ Royal Netherlands Institute for Sea Research, has been awarded the prestigious Marsh Award for International Ornithology by the British Trust for Ornithology (BTO). The award, which is presented annually, is given to an individual scientist whose work on the international stage has had a significant influence on British ornithology. This year, the Marsh Award for International Ornithology has been awarded to Professor Theunis Piersma in recognition of his scientific work on migration, ecology and evolution of birds and other taxa.
Using Red Knots and Black-tailed Godwits as the maina study species, Theunis and his group established a framework to predict the physical attributes and behaviour of individuals based on climatic, disease and food related factors. His work as also focused on the evolutionary trade-offs involved in predation and anti-predatory behaviour across different species along the food chain. This work, in particular, holds high policy-relevance, as it informs on the risk of overexploitation of marine areas as well as our countryside.
Professor Piersma was also one of the driving forces in establishing the Global Flyway Network, which focuses on long-term demographic studies of shorebirds to identify natural selection pressures on this beleaguered group of birds.
Dr Daria Dadam, BTO, said, “Theunis is a very worthy recipient of the Marsh Award for International Ornithology. His work on shorebirds has revolutionised the way we think about how these birds interact with the habitats they live and feed in. Without this we would have a much poorer understanding of just how important our marine areas are for them, and how even small changes can have consequences for these global travellers.”
Professor Theunis Piersma, said, “The Marsh Award is a fantastic recognition of what we have been trying to achieve as an international team, carefully deciphering the ecological factors determining their distributions and numbers, what these epic migrants have to say about the state our shared world. As deeply amazing the shorebirds are in their own right, they also have a role for us to play as the canaries in the global coal-mine.”
As well as a leading academic, he is also a dedicated mentor to the younger generation of scientists. He has supervised 50 PhD students and 20 postdocs, and he and his team hosts visiting students and scientists from all over the World.
Marsh Award for International Ornithology is run in partnership with the British Trust for Ornithology (BTO) and recognises an individual scientist whose work on the international stage has had significant influence on British ornithology, especially as reflected in the work of BTO scientists and volunteers.
In the middle of August we finished our field season of 2017 and returned from Khairusova-Belogolovaya estuary in Western Kamchatka. Unfortunately this year we could not involve foreign volunteers. The funds for the expedition were only secured at the end of May and it was impossible to organise all necessary paperwork for visas and the like on time.
Five researchers from different organizations took part in the expedition: Dorofeev Dmitry, Ganiukova Anna, Ivanov Anton, Matsyna Alexander and Shupikova Anna. Our studies were supported by the All-Russian Research Institute for Environmental Protection and the MBZ species conservation fund.
The largest part of our activities were dedicated to Great Knot (Calidris tenuirostris). This year we modified our trap and caught more than 500 waders, 360 were marked with Black\Yellow engraved flags. We already have five re-sightings from Japan, Korea and China. About 130 birds were juveniles, which is key because it is very important to know if there are differences in migration between adult and juvenile birds.
The next important part of our work was searching and reading engraved leg flags. In the end of the season we had a total of 1526 records in our log book! In 2016 we had about 1800 records, but considering that this year we had only one good scope instead of four, the results were very good. More than 75% of the observations were made with the high quality scope that the Royal NIOZ lend us, just for this field season. For the next field season we hope to find additional funds to buy a high quality scope for the project.
Most of our re-sightings were of Great Knots colour-banded or flagged in Australia, China and Kamchatka. We also collected records of marked Black-tailed Godwits, Bar-tailed Godwits, Red Knots, Red-necked Stints and Dunlins. Observed waders were banded at least at 22 sites within the East Asian-Australasian Flyway, from Chukotka (Russia) to Victoria (Australia) and New Zealand. These data allows to calculate new estimates of the duration of the stopover of individual birds.
On the penultimate day of our field season we had a very nice surprise. While we were out doing observations we recorded the more or less famous Great Knot “EI” who was observed in winter 2017 near Dubai. This male Great Knot had started his southward migration very late so we can suppose that he had a successful breeding season!
Wader counts are also the part of our work. But, unfortunately, not the best part. Khairusova-Belogolovaya estuary is rather large, about 50 km2, and it is impossible to make total counts. So we have minimum estimates for the study site. Number of Great Knots varied from 23,0000 in the beginning of July to 4,500 in the middle of August.
Also this year we repeated the benthos survey that we have been conducting since 2015. In total 201 sample were taken on the whole territory within a 500 by 500 m grid. This investigation will help us understand if there are any dynamics in benthos distribution between years.
The last, most important, activity of our team were observations on foraging juvenile Great Knots, that just arrived from the tundra zone to the mudflats, and on foraging adult Great Knots. In previous years we had noticed that juveniles feed much more slowly than adults. We think that juveniles do not have enough experience with feeding on bivalves. At breeding grounds they are used to feed on various insects, changing to bivalves might be a challenge for them.
The last goal of our studies was collecting information about rare species – Spoon-billed Sandpiper and Far-Eastern Curlew. We have rather detailed data about numbers and distribution of the Far-eastern Curlew in the estuary. From the middle of July till the beginning of August about 300-350 birds were feeding on the mudflats the closest to the camp. At least several dozens of Curlews used the most remote part of the estuary. This year we had not enough scopes and people to look for Spoon-billed Sandpipers. Only in the end of the season we were able to check types of mudflats that is preferred by this species. At that time juvenile birds started their southward migration.
We are grateful for all our colleagues from different countries who helped us with information and advice. Especially we appreciate the local people who helped us with storing expedition stuff and accommodation.
Amalia is back in Africa! He is in Senegal, in the wetlands and rice fields of the Casamance (see map). Amalia is a satellite-tagged male Black-tailed Godwit who’s claim-to-fame is that we are now following him for four and half years!
He is carrying a transmitter since 2013, the longest of all godwits we track. He actually is a superstar in Friesland, The Netherlands, where his arrival each year is awaited and celebrated by the local community and school classes – including a contest to predict his arrival date. Through satellite tracking we are learning a lot about ‘our’ Godwits, and especially multi-years tracks such as from champion Amalia, are extremely valuable.
This year Amalia again spent the breeding season in Friesland, The Netherlands. That was no surprise: he has come back to the breeding grounds in Friesland for five years now.
What was a nice development this year is that on 27 May 2017 Jos Hooijmeijer reported that Amalia was seen with very young chicks!. You can read about it here. He apparently found a mate and together they hatched a brood.
What happened to the precious brood Amalia was guiding in May?
Based on Jos’ visit in May we estimated that the laying date has been around 25 April . That is quite early and probably this was his first clutch in 2017. Jos again visited the breeding site of Amalia in Friesland on 9 June 2017, when the chicks would be about 20 days old.
Jos found Amalia only a few hundred meters from where he saw Amalia and his family on 27 May. Amalia’s mate was leading two or three chicks through a pasture grazed by horses and Amalia was sitting on a pole, a good lookout to watch over them.
The chicks were not captured and ringed, so we cannot say with 100% certainty whether they fledged or not. However, if indeed on June 9th there were two or three chicks that survived for 20 days, there is a fair chance that at least one will have survived for 25 days, to the age of fledging.
One of the last observations of Amalia in The Netherlands was on 15 July 2017. That day he was seen by Jelle Loonstra near the town of Jeth, in a group of nine adults and 12 recently fledged juvenile birds. Maybe one of more of these fledglings were his own chicks!
The next day, Amalia was still in Jeth, but he left soon after because on the 18th he had arrived in SE England, in the estuary of the River Alde (NW of Ipswich). The same day he flew back to the mainland, to the Hoge Plaeten in de Westerschelde bij Breskens (The Netherlands).
From Breskens, he started his southward migration. On 20 July, he was in the vast “marais” wetlands south of Rochefort in Charente Maritime (France), a well-known stopover for Black-tailed Godwits, especially in spring. There he stayed until the end of July or early August (he was 10 days of the radar), to fly to the Casamance in southern Senegal where he arrives on August 12, as in previous years. He is not only faithful to his Friesian breeding area but also to his Senegalese wintering area.
The best way to find raptors is to observe their prey. As soon as a shorebird tilts its head to point one eye up, a raptor must be looming overhead. Their skills in detecting predators exceed those of the best birder — after all, their life depends on their attentiveness. That is why scanning behaviour is commonly used as a reliable indicator of the danger level that animals perceive.
But, how reliable is it really? How do we know what a bird is really looking at?
My first doubts come up in Chile, in 2005. At midday we drive through the sweltering desert of Atacama. A carpet of salt crystals stands out against a bluegreen lake where flamingos are slobbering crustaceans. The sky is clear blue. The white clouds in the distance turn out to be the snowy peaks of the Andes.
Sure enough, there is a shorebird on the salt. It is a Baird’s Sandpiper (Calidris bairdii), and it is alone. The bird is not shy; we can even see that it is eating little white critters, probably amphipods. As I come even closer to take pictures the bird starts tilting its head several times as if scanning the sky overhead. I look up to seek for the raptor. There is none.
A little further down we see another loner on the salt plains: a Puna Plover (Charadrius alticola). Likewise, the plover is not shy, and as I approach to make pictures, this bird also tilts its head, just as the Baird’s did. Again, not a bird in the sky. I’m confused.
These observations linger in my head for some time, until Graham Martin, the King of Bird Vision, visits our institute. I bombard him with questions and pictures: Would the birds really look at the sky overhead? Could they be looking at me instead? Does the bright sunlight have something to do with it?
It is likely that the bird sees me as a predator. By scanning the sky, he may be anticipating his chances: if I decide to flee for this ground predator, could I be intercepted by an attacker from the sky?
However, birds can also keep their head tilted for another reason, explains Graham. Just like us, birds have a pecten oculi, the organ that causes the famous blind spot in the field of vision. This organ ensures that the retina receives sufficient nutrition. In birds, the organ may have yet another function: its dark dyes and velvety structure ensure that incoming light is strongly absorbed. By turning their heads, birds could make sure that the bright sunlight falls right on the pecten. As a result, they can reduce glare in the eye and prevent being temporarily blinded by the sun. Calculations by Graham confirmed that the head positions of the photographed birds were appropriate for his effect to occur. We published our ideas, thereby explicitly acknowledging that our sample size is only two (van den Hout & Martin 2011, Wader Study Group Bulletin 118: 18-21).
Since then I have been keen on trying to find out whether more birds exhibit such scanning behaviour in a predator-free context. And indeed, I observed and photographed several more scanning events, both from the northern and southern hemisphere, that could clearly not be connected to a raptor flying overhead. The pictures are shown below.
Like with the Atacama birds, it appeared that all pictures were taken around midday (and this was not planned!), when the sun was high in the sky. These observations seem consistent with the idea that by tilting their heads, the birds prevent disability glare from the sun, as in our 2011 paper. Although these observations do not conclusively solve our scanning issue, it makes the matter all the more intriguing, and compelling to solve.
Ginny (Ying Chi) Chan, Theunis Piersma and Chris Hassell from Royal NIOZ Netherlands Institute for Sea Research, University of Groningen, The Netherlands and Global Flyway Network Australia, report:
This is a story about the ten thousand kilometer journey of a Bar-tailed Godwit, travelling between the tropics and the Arctic, between pristine and industrial environments, and between different nations and cultures.
Some background facts: menzbieri godwits are somewhat largish shorebirds, who breed in the Russian Arctic and “overwinter” on the hot coasts of NW Australia, and therefore migrate along the coasts of the Yellow Sea in China twice a year. Many intertidal zones along this flyway are threatened. Tracking shorebirds (and their populations) with satellite transmitters on their annual migrations is necessary to target conservation action to the right places. From the tracks, we can identify the (remaining) crucial intertidal mud flats for long-haul migrants in China and along the East Asian-Australasian Flyway.
We give Bar-tailed Godwits satellite transmitters in NW Australia, and every spring we literally ‘follow’ these tagged godwits twice! By surveying their staging sites in China, and watching the data come in from the transmitters. This the journey of Bar-tailed Godwit Y5RBRL in 2017:
15th February 2017
This bird (a female) with colour-ring combination Y5RBRL was caught, had a satellite transmitter attached, and was released at Eighty Mile Beach, NW Australia on 15 February 2017. What did we learn most from Y5RBRL and her tracks?
19th April 2017
Y5RBRL left Eighty Mile Beach and made an impressive non-stop flight of more than 5,700 km to China. In five days she reached the Rudong coast (Tiaozini-Dongsha mud flats) in Jiangsu Province, where she stayed for about a week.
3rd May 2017
She headed further north and reached Diaokou on the coasts of southern Bohai Bay on 3 May. Our field team reached Diaokou ten days later on 13 May.
15th May 2017
On 15 May 2017, our field team reports that they had sighted a Bar-tailed Godwit carrying a satellite transmitter in Diaokou Xiang, Lijin County of Shandong Province. Yueheng (a volunteer fieldworker) saw this special bird with an antenna sticking out. It is very special to actually see a bird with a satellite transmitter in the field, thousands of kilometers away from where you marked it.
Diaokou in southern Bohai Bay has been sampled for benthic prey and surveyed for birds since spring 2016. Another tagged Bar-tailed Godwit had stopped there last year. Y5RBRL stayed in Diakou until 25 May, a total of 22 days. It seems to be an important staging site, although we did not see big numbers in both years. It is difficult to find and approach flocks there, because there are a lot of fishermen working on the mud flats and we only had three days to do our work. More regular surveys in this area will be very informative.
From Diaokou Y5RBRL flew to her breeding grounds near Chersky in northern Russia. She didn’t flew non-stop, she stopped at several places in the tundra. Was she looking for a mate or a good place to breed? Or waiting for the snow to melt?
7th June 2017
Finally she reached her breeding location! From our track we infer she stayed at this single site for 26 days. As our transmitters are in a cycle of 8 hours “ON” 25 hours “OFF”, she could have been there for 28 days. It is very likely she attempted to breed but our movement data cannot confirm whether this was successful. The egg-laying takes four days and incubation takes 21 days, so if her chicks hatched successfully, she would have left them for her partner to take care of the chicks. For shorebirds, it is not uncommon that one parent leaves the responsibility of raising the chicks to the partner.
3rd July 2017
After the breeding season she flew further north to the New Siberian Islands. She was at this site ‘fueling up’ for almost 16 days, to get ready for her southward migration.
Now as we write this in mid August 2017, Y5RBRL has returned to Diaokou for some more fueling. Obviously Diaokou is known to her as a good site to prepare for migratory flights.
What we are wondering now is if she will use the Tiaozini-Dongsha mudflats again before flying to Australia. Why is that such an important question? This staging site, which Y5RBRL used as first landing and refueling place after her long haul flight from Australia, is part of a huge ‘reclamation’ project and the mud flats will soon disappear. Ying Chi and colleagues used the local movements of Y5RBRL and 14 other tagged Bar-tailed Godwits to show that the planned industrialisation overlaps with the areas that the birds feed in on the Tiaozini-Dongsha mud flats and shoals. This result is presented in a Forum paper in Wader Study published by Global Flyway Network and colleagues in early August. We hope that the publication can urge the government to re-assess the plans. If we want to make sure Y5RBRL can keep using her favorite staging sites (and ca. 60,000 other godwits with her) action is needed.
Today a Forum paper was published in Wader Study, authored by Theunis Piersma and colleagues from China, Australia, America and New Zealand, reflecting on development plans of the coastal zone of Jiangsu Province – China.
The international team of shorebird scientists and intertidal experts says that the expected ecological impacts of reclamation of coastal and offshore mudflats in this area warrant new Environmental Impact Assessments.
The team describes in details how our satellite tracking data of shorebirds (see earlier blogs and figure below) together with insights in the functionality of tidal flat zones, emphasize the ecological value of two areas areas that are scheduled to be reclaimed soon: Tiaozini mudflats and the offshore Dongsha Shoals.
By summarizing a broad range of studies on shorebirds, Theunis Piersma and colleagues from China, Australia, America and New Zealand sketch the expected ecological impact of the developments on shorebirds, a.o. on two especially vulnerable species, Spoon-billed Sandpipers (Critically Endangered) and Nordmann’s Greenshanks (Endangered).
Curious to understand more about oversummering waders in West Africa, we set out to count our study areas in Parc National Banc d’Arguin, Mauritania.
During counts between 9 and 15 July 2017, carried out by the GFN team consisting of Ahmed Medou, Ahmed Amarajeyat, Mohamed Camara, Jan van Dijk and Bob Loos, a total of almost 65,000 birds were counted at six sites near Iwik, Mauritania (see map).
During high tides, the islands of Arel, Nair and Zira were counted, together with the coast of Ebelk d’Aiznaya and part of the Baie d’Aoutief.
The highest numbers were recorded for Flamingo (13,800), Curlew Sandpiper (12,614!), Dunlin (7,758) and Bar-tailed Godwit (5,046). Surprisingly, only 1,357 Red Knots were counted.
The last census of oversummering waders in Banc d’Arguin dates back to June 1988 when the entire area was counted between 8 June and 3 July during a WIWO expedition.
Comparison of the results with 1988 is not yet possible because the results per counting area from 1988 are not yet available. However we know that in June 1988 on Arel 2,400 Sanderlings and 1,400 Curlew Sandpipers were counted. We arrived at 2,450 Sanderling, and a spectacular number of more than 10,000 Curlew Sandpipers!
As expected, the majority of the oversummering waders were “young” birds, born in the previous summer and now in their second calendar year.
We also collected more than 300 colour-ring re-sightings from, among others, Red Knots, Bar-tailed Godwits, Curlew Sandpipers, Whimbrels and Spoonbills (both the local breeding birds of the subspecies balsacii and birds from the Dutch breeding population that decided to oversummer). More about those birds next time!
For curious readers we included the count data below.