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Can machines replace humans?

Article authored by Deborah Buehler It’s a thought-provoking question. Especially at moment when machines – and algorithms more broadly – are increasingly impacting our lives1. However, one might understandably say that further clarification is needed. What type of machines? What task is to be done? In this issue of Wader Study, Roberto Valle and Francesco Scarton highlight the nuanced way this question could be answered2. Of course, they don’t ask whether machines can replace humans, exactly. They just want a safe and accurate way to count nesting shorebirds and they wonder if machines might help. In this case, the machines are unmanned aerial systems, also known as ‘drones’, a name that may be an onomatopoeia for the mosquito-like noise they make. Drone technology can be useful as well as annoying. Many fields of study have used drones from military intelligence, to civil engineering, to archaeology, to mining; and wildlife biology is no exception3. If you had to count something, in inhospitable territory, wouldn’t you send in the drones? Valle and Scarton needed to count breeding pairs of their study species, Black-winged Stilts Himantopus himantopus and Pied Avocets Recurvirostra avosetta. These birds make nests in difficult-to-reach saltmarshes in the Lagoon of Venice, a 55,000 ha coastal wetland in northeastern Italy. The lagoon is the largest in the Mediterranean Sea and the area is full of soft mud and tidal channels, both of which are easier to fly a drone over than to walk on. [caption id="attachment_14742" align="alignnone" width="960"] Saltmarshes in the Lagoon of Venice in northeastern Italy (photo: Roberto Valle)[/caption] However, before sending in the drones, Valle and Scarton needed to know that the technology could accurately and safely count the birds. Therefore, they compared the safety and effectiveness of drone-conducted counts with traditional ground-based counts. The researchers conducted fieldwork from mid-April to mid-June during the 2017 and 2018 breeding seasons. Surveys were restricted to days with windspeeds less than 10 km/h and no clouds because, although human researchers often work in wind and rain, drones require better weather. Drone and ground surveys took place at 52 colonies over the two years, always either in the morning from 8 am to 10 am or in the afternoon from 4 pm to 6 pm to avoid extreme temperatures. The safety of the birds was top priority, especially since drones are a newer technology. Therefore, the researchers launched drones from sites more than 150 m from the study colony and then flew at a height of 70m until they were directly above the centre of the colony. This ensured that the drone wouldn’t disturb the birds before the survey had started. Much like humans, birds don’t like it when things plummet vertically towards them. For this reason, the researchers used the “lawn mower” pattern, systematically flying back and forth, to lower the drones when it was time to begin the survey. Once the drone was lowered to about 30m, the pilot could see the nests, but couldn’t be certain whether there was a bird present at the nest. Thus, the researchers lowered the drone a further 10 to 20 m.  At this height, they flew above the nests at a speed of 15 to 30 km per hour, causing any birds to flush (fly away) from their nests. Disturbing the birds was necessary to record reactions to the drone. These reactions were coded in the field or later from videos as follows: birds sitting on or flushing from a nest were considered a breeding pair, birds strongly reacting to the drone by chasing it were considered probable breeders, even if far from a nest, and the researchers counted one pair for every two birds behaving this way. During each drone flight, a researcher observed the colony from approximately 150 m to check whether nests or young were in danger of predation after the adults were flushed from the nests. Thirty minutes later the researchers approached the colony on foot for the ground survey. During a ground survey, two researchers walked abreast about 10 m apart systematically searching for nests. Every nest with eggs or chicks was recorded as ‘confirmed breeding’. Ground surveys were always done after drone surveys even though the researchers admit that this is a limitation in terms of the comparison of methods. A completely fair comparison would have randomized the order of the surveys. However, in this study, randomization was intentionally traded for the ability to use the ground survey as a safety check on the preceding drone survey. The researchers found no evidence that drone surveys cause undue disturbance to birds. Birds were not scared permanently from their nests, nor were the nests exposed to predators. In fact, the drones caused less disturbance to the birds than humans on the ground. Drone surveys also took less researcher time, even accounting for post-processing work in the lab after drone surveys. Drones were therefore safe and efficient, but were they accurate? Unfortunately, no. Valle and Scarton found that fewer breeding pairs were identified during drone flights than ground counts. This undercounting was substantial, with 18.1% of Black-winged Stilt pairs and 20.5% of Pied Avocet pairs missed during the drone surveys. Furthermore, drone surveys had less sensitivity (true breeding pairs identified as positive), specificity (true non-breeders identified as negative), and accuracy (correctly identified birds divided by the total birds seen). This study shows that there are pros and cons to using drones when surveying nesting shorebirds. Drones did not detect as many nests as ground surveys and falsely identified some nests; however, the drone surveys caused less disturbance to the birds. These results raise the question of whether accuracy could be improved with improved drone technology or whether drones could be useful under some, if not all, circumstances? Valle and Scarton admit that a limitation of their study was the type of drone used. It was a simple model with a standard camera. A larger drone with a higher quality camera might have provided better images and allowed the researchers to distinguish incubating birds from a higher altitude without flushing them from nests. This might improve accuracy while further decreasing disturbance to the birds, but this remains to be tested. The researchers also found that the size and composition of the breeding colony mattered. In large, mixed colonies, birds flushed when the drone was still quite far away in response to alarm calls from only a few species. For example, the presence of Eurasian Oystercatchers Haematopus ostralegus made this worse because they are very aggressive towards drones. This contributed to undercounting because it was more difficult to identify breeding pairs when the adults were no longer at their nests. Furthermore, if nesting birds were flushed out of sight of the drone pilot, they weren’t counted. The opposite was also a problem, if the same bird repeatedly chased the drone, within the line of sight, it could be double counted. [caption id="attachment_14744" align="aligncenter" width="960"] Eurasian Oystercatcher reacting to drone. (photo: Roberto Valle)[/caption] Knowing that large, multi-species colonies contributed to errors in the drone surveys, the authors asked whether drones might be most useful for smaller colonies of mainly silts and avocets. This was indeed the case. The authors found that both the sensitivity and specificity of the drone surveys were increased in small colonies and that in these circumstances there was nearly perfect agreement between the drone and ground survey methods. So, can machines replace humans? It's a question best answered with context taken into account. In this study, the machines are drones and the task is counting breeding shorebirds. The authors recommend the use of drones only in small colonies without species, like Eurasian Oystercatchers, that react more strongly to drones. In these circumstances, drones provide high accuracy, low disturbance, and shorter time to complete a survey. In other circumstances, the authors do not recommend the use of drones. More broadly, context becomes even more important when asking whether, when and how machines might replace humans. Our world is full of technologies that were unimaginable less than a generation ago. Yet we use these technologies daily and they affect all aspects of our lives4. Machines can do many things better than humans, but there remain many things that humans can do better than machines. We can be empathetic, we can question our own biases, we can use our humanity to fight against rules that shouldn’t be automated5. This study reminds us that striking a balance where context is taken into account may be the best way to synthesize the strengths of both our machines and our own human minds.  
  1. Demetis, D. 2019. Algorithms have already taken over human decision making. Posted in The Conversation 8 Mar 2019 at https://theconversation.com/algorithms-have-already-taken-over-human-decision-making-111436.
  2. Valle, R.G. & F. Scarton. 2020. Feasibility of counting breeding Pied Avocets and Black-winged Stilts using drones. Wader Study 127(3): 257–265.
  3. Hodgson, J.C., R. Mott, S.M. Baylis, T.T. Pham, S. Wotherspoon, A.D. Kilpatrick, R.R. Segaran, I. Reid, A. Terauds & L.P. Koh. 2018. Drones count wildlife more accurately
and precisely than humans. Methods in Ecology & Evolution 9: 1–8.
  1. Deibert, R. 2020. Reset: Reclaiming the Internet for Civil Society. House of Anansi Press, Toronto, Canada
  2. Kantayya, S. (Director). 2020. Coded Bias [Documentary film]. Trailer available at https://www.youtube.com/watch?v=jZl55PsfZJQ
Spotlight: Drone vs. human surveys of breeding shorebirds

Can machines replace humans? Article authored by Deborah Buehler It’s a thought-provoking question. Especially at moment when machines – and algorithms more broadly – are increasingly impacting our lives1. However, one might understandably say that further clarification is needed. What type of machines? What task is to be done? In this issue of Wader Study, Roberto Valle and Francesco Scarton highlight the nuanced way this question could be answered2. Of course, they don’t ask whether

The IWSG Small Project Grants Committee have decided to extend the deadline for application to 31st December 2020. With this grant we aim to support shorebird studies that otherwise will not go ahead. This could be all sorts of projects related to waders (shorebirds): ecological and/or conservation research, pilot studies looking at biological aspects of a single or a few species, or counts of staging birds at unexplored sites. Or something completely different! Application is open for IWSG members who have a project idea that could be undertaken if supported with a small amount of money (currently 1000 Euros per project). About the grant: https://www.waderstudygroup.org/projects/small-grants/ The application form: https://www.waderstudygroup.org/wp-content/uploads/2018/11/IWSG-grant-application_28112018_form-Word.doc   The IWSG Small Grant Committee Yahkat Barshep, Vojtěch Kubelka and Jannik Hansen
Extended deadline for IWSG Small Project Grant applications

The IWSG Small Project Grants Committee have decided to extend the deadline for application to 31st December 2020. With this grant we aim to support shorebird studies that otherwise will not go ahead. This could be all sorts of projects related to waders (shorebirds): ecological and/or conservation research, pilot studies looking at biological aspects of a single or a few species, or counts of staging birds at unexplored sites. Or something completely different! Application is open for IWSG

ÉLVONAL Shorebird Science is happy to announce the IV. ÉLVONAL conference “Sex roles and breeding ecology of shorebirds during 8–9 January 2021, which will be held as an online meeting. Find attached the conference leaflet as well as the advert to the current PhD position within ÉLVONAL Shorebird Science project: IV.ELVONAL Conference Flyer ELVONAL PhD Sex roles and breeding ecology The conference will focus on current achievements and future plans of ÉLVONAL teams across the globe and will be enriched with invited speakers and targeted webinars at nest fate determination, trapping techniques and behavioural observations of shorebirds. Any researcher, conservationist or student interested in breeding ecology of shorebirds can use this opportunity to join us from anywhere and discuss recent advances in the field. The conference participation is free of charge and registration is open until 20 December 2020. You can register here: https://forms.gle/wXJR2PAY3w8QWsbr6 We are looking forward to meeting you online! Vojtěch Kubelka (on the behalf of the organizing team) Featured image: Flying Banded Stilts (Cladorhynchus leucocephalus) in Australia. © Vojtěch Kubelka
IV. ÉLVONAL Conference | Virtual event and PhD position advert

ÉLVONAL Shorebird Science is happy to announce the IV. ÉLVONAL conference “Sex roles and breeding ecology of shorebirds” during 8–9 January 2021, which will be held as an online meeting. Find attached the conference leaflet as well as the advert to the current PhD position within ÉLVONAL Shorebird Science project: IV.ELVONAL Conference Flyer ELVONAL PhD Sex roles and breeding ecology The conference will focus on current achievements and future plans of ÉLVONAL teams across the globe

https://shop.curlewaction.org/wp-content/uploads/2020/11/cropped-cropped-cropped-curlewaction1-250x139_51fa4b278b91f89f5eaaf5b78307a33b-1.pngCurlew Action is working to support effective conservation of Eurasian Curlew across Britain and Ireland by providing practical help, raising awareness, increasing natural history education and develop cooperation with farmers and land managers to reverse its decline and ensure its survival. This year, Curlew Action offers you to support their actions with Christmas Cards beautiffuly illustrated by the artists Jessica Holm and Mark Gibbs: [caption id="" align="aligncenter" width="385"]https://shop.curlewaction.org/wp-content/uploads/2020/11/17A3BEFF-349F-4B64-847A-4D73CEC1DD0F.jpeg Artist Jessica Holm's Christmas card called ‘Winter Curlews’ exclusively available at: https://shop.curlewaction.org/.[/caption] The cards will be in stock by 14th November, and are available for pre-order now. Support Curlew Action for Christmas at: https://www.curlewaction.org/shop/.   Featured image: ©Dr. Georg Wietschorke - Pixabay.
Curlew Christmas Cards | Curlew Action

Curlew Action is working to support effective conservation of Eurasian Curlew across Britain and Ireland by providing practical help, raising awareness, increasing natural history education and develop cooperation with farmers and land managers to reverse its decline and ensure its survival. This year, Curlew Action offers you to support their actions with Christmas Cards beautiffuly illustrated by the artists Jessica Holm and Mark Gibbs: The cards will be in stock by 14th November, and are

During the Annual General Meeting of the 2020 IWSG conference (10-11th October), members unanimously vote to support objection to Tagus Estuary airport development. Please find the statement of the IWSG signed by our chair, Jennifer Smart, on our AGM Minutes & Reports web page or directly there:   Read the Graham Appleton blog entitled "Tagus estuary: for birds or planes?" that emphasise the vital role of the Tagus estuary for shorebirds on WaderTales https://wadertales.wordpress.com/2019/12/23/tagus-estuary-for-birds-or-planes/.   Featured image: Tagus Estuary Nature Reserve. (c) Paulo Valdivieso - Wiki Commons.  
Impact of the proposed airport on the Tagus Estuary, Portugal | Declaration of the IWSG, October 2020

During the Annual General Meeting of the 2020 IWSG conference (10-11th October), members unanimously vote to support objection to Tagus Estuary airport development. Please find the statement of the IWSG signed by our chair, Jennifer Smart, on our AGM Minutes & Reports web page or directly there:  

Following counts of Golden Plovers in Europe in 2003, 2008 and 2014, we are aiming at having coordinated counts of the species on 10-11th or 17-18th October 2020. In some countries, there are already coordinated waterfowl counts during one of these weekends. Each country will pick one of the two weekends. The counts focus on Golden Plovers, but we would like to ask all participants to use this opportunity to include Lapwing and Curlew in the counts. The status of both species in Europe is of high interest, not least in terms of conservation. Countries participating are: Austria, Belgium, Czechia, Denmark, Estonia, Faroe Islands, Finland, France, Germany, Hungary, Iceland, Ireland, Netherlands, Poland, Portugal, Sweden, Switzerland and United Kingdom. Due to the late start of this project, some countries won’t be able to coordinate counts in the way they would like, but will ask their membership and/or other volunteers to report Golden Plovers, Lapwings and Curlews on the specific weekend and report it through the specific country’s reporting systems/databases. We would like you all to register the counts within separate sites with the coordinates, and preferably a note of which sort of habitat this site is. Other European countries not currently on this list are very welcome to join. We have been contacting people in other countries and have either not heard from those contacts or they have come back to say that unfortunately, they could not help this time around. After 7th October is a deadline, we have set for countries to join our efforts. If you would like to join the efforts and your country is on the list please e-mail GoldenPlover2020@mail.com for a contact to your country coordinator. The number from previous counts:
Country Major population group Total 2003 Total 2008 Total 2014
Belgium Continental [2000] 3229 n.c.
Bulgaria Continental n.c. 3 n.c.
Czechia Continental n.c. 94 1239
Denmark Continental 380000 270774 291204
Estonia Continental n.c. 887 118
Finland Continental n.c. 1210 n.c.
Germany Continental 220000 193231 *
Hungary Continental n.c. 138 *
Latvia Continental n.c. 0 2938
Lithuania Continental n.c. 22244 n.c.
Netherlands Continental 180000 167160 153297
Poland Continental 22000 52630 69222
Sweden Continental 115000 139557 135120
Iceland Atlantic n.c. 7662 n.c.
Republic of Ireland Atlantic 24000 56841 35760
United Kingdom Atlantic 143000 152847 180592
* Data collected, but currently unavailable; n.c. = no counts   IWSG Golden Plover Project <GoldenPlover2020@mail.com>   Featured image: European Golden Plover Pluvialis apricaria, Vlieland - Vallei van Malgum, the Netherlands. ©Wouter van der Ham, 12-10-2016 on waarneming.nl
European Golden Plover Survey 2020

Following counts of Golden Plovers in Europe in 2003, 2008 and 2014, we are aiming at having coordinated counts of the species on 10-11th or 17-18th October 2020. In some countries, there are already coordinated waterfowl counts during one of these weekends. Each country will pick one of the two weekends. The counts focus on Golden Plovers, but we would like to ask all participants to use this opportunity to include Lapwing and Curlew in the counts. The status of both species in Europe is of

Dr. Scott Flemming was recently hired by the Council’s Conservation of Arctic Flora and Fauna Working Group (CAFF) and the International Arctic Science Committee (IASC) to study how shorebirds breeding in the Arctic are impacted by plastic contamination. He is working in conjunction with Dr. Rick Lanctot (Alaska Shorebirds Coordinator with the United States Fish and Wildlife Service) and Dr. Jennifer Provencher (Environment and Climate Change Canada).
To better understand this potential problem, they conducted a literature review of plastics and shorebirds. Unfortunately, few studies have investigated the presence or quantity of plastics in shorebirds. Consequently, they are reaching out through listservs and various social networks to accomplish the following objectives: 1. Collect unpublished reports and learn about data available on plastic pollution ingestion in shorebirds worldwide. 2. Connect with researchers who are currently carrying out, or wish to learn more about, plastic pollution ingestion in shorebirds. 3. Assess if the factors we think make shorebirds susceptible to plastic pollution are correct, identify taxa that may be especially susceptible to plastics, and determine areas of future research. 4. Gauge interest in potential collaborations for the collection of carcasses and fecal samples for plastic pollution studies in the future.
To help with this effort, they would appreciate you answering this survey comprising six questions by Monday September 14th: https://docs.google.com/forms/d/e/1FAIpQLScOykZANnxcrgXf_Gb0itjwZ9kl1VUzeL1nvILO4oMfp5wmNg/viewform If you have an questions or would like to follow-up please contact Scott Flemming: scott.flemming@canada.ca  
Shorebird Plastic Ingestion Survey | Conservation of Arctic Flora and Fauna-International Arctic Science Committee

Dr. Scott Flemming was recently hired by the Council’s Conservation of Arctic Flora and Fauna Working Group (CAFF) and the International Arctic Science Committee (IASC) to study how shorebirds breeding in the Arctic are impacted by plastic contamination. He is working in conjunction with Dr. Rick Lanctot (Alaska Shorebirds Coordinator with the United States Fish and Wildlife Service) and Dr. Jennifer Provencher (Environment and Climate Change Canada). To better understand this potential

If you haven't already received it, you will find below a message co-signed by Jen and Mark Smart thanked IWSG Member for their support to their fundraising bike ride: Dear IWSG Member, We have finished our epic fundraising bike ride – 603 miles and over 6000m of climbing in 8 days. It was one of the best but hardest things we have ever done, and the British weather certainly made us earn every single donation. I would like to say a massive thanks to the IWSG members we saw on the way, the lovely messages we received and a huge thanks to Elwyn Sharps who was masterminding the social media accounts that really help to spread the word and to Katharine Bowgen for sending these emails. Thanks, so much for all your support for IWSG small grants. So far, we have raised over 2000EU. There is still time to donate here https://www.waderstudygroup.org/donate/. Once again thanks. Best wishes Jen (incoming Chair) & Mark Smart   Featured image: (c) Project Godwit https://projectgodwit.org.uk/
A massive thank you from Jen and Mark Smart | 603 miles completed and over €2000 raised!

If you haven't already received it, you will find below a message co-signed by Jen and Mark Smart thanked IWSG Member for their support to their fundraising bike ride: Dear IWSG Member, We have finished our epic fundraising bike ride – 603 miles and over 6000m of climbing in 8 days. It was one of the best but hardest things we have ever done, and the British weather certainly made us earn every single donation. I would like to say a massive thanks to the IWSG members we saw on the way, the

The IWSG have received a request to pass on details of a new study on backpack transmitter attachment effects that is looking for input from shorebird researchers around the globe. The research team from the USGS lead by Rick Lanctot and Emily Weiser aims to compare the success of various methods of deployment of back-mounted transmitters on shorebirds. For that they are asking for people to download a spreadsheet (access here:https://drive.google.com/file/d/1PWzcy3UOrf5eG8i6qaPiEcYlKE1LQRTK/view?usp=sharing) and answer the questions for your particular projects before sending it back to Emily Weiser at eweiser@usgs.gov by the 15th September 2020. Full details on the original email sent to WHSG Listserv 18th August 2020 can be find here: Backpack-transmitter-attachment-effects-on-shorebirds.pdf. If you have any further questions or issues with the Google Doc please direct your request to Emily Weiser.   Featured image: Common Redshank Tringa totanus, April 2017, Lake Geneva, Wisconsin, USA. ©Christoph Müller.  
Backpack transmitter attachment effects on shorebirds | Questionnaire request

The IWSG have received a request to pass on details of a new study on backpack transmitter attachment effects that is looking for input from shorebird researchers around the globe. The research team from the USGS lead by Rick Lanctot and Emily Weiser aims to compare the success of various methods of deployment of back-mounted transmitters on shorebirds. For that they are asking for people to download a spreadsheet (access

Scientific research often begins with a mystery – something in the data that makes the researchers think – Huh? That’s funny. In this issue of Wader Study, authors Lindström and Alerstam begin their paper1 with just such a mystery. The researchers studied the 5,000–7,000 km non-stop flights that Great Snipes Gallinago media make during migration from central Sweden to equatorial Africa (and back). To do this, they attached tiny sensors (called mini-multisensory accelerometers) to the bird’s lower leg (tibia). These sensors that weigh less than two grams and measure ambient temperature and pressure every hour and movement every five minutes2. [caption id="attachment_14028" align="alignnone" width="700"] Great Snipe outfitted with a mini-multisensory accelerometer on the tibia. (photo: Åke Lindström)[/caption] The ability to collect data at this level of detail from high flying birds (literally migrating at cruising altitudes above 4000 m) is astounding. However, the researchers found themselves struggling to interpret some of the data. In several of the 15 flights studied, there were periods when activity suddenly stopped, and temperature rose. It looked like the bird had landed, but air pressure remained low suggesting the bird was still at high altitude. Then, usually in under an hour, activity was high again and temperature low. It was a mystery. After ensuring that the data were not due to a technical malfunction, the researchers started to ponder other explanations. As previously mentioned, the sensor sits on the bird’s lower leg. Unlike birds that perch (Passerines), which tend to fly with legs tucked up against the body, most shorebirds fly with their legs stretched out under the tail. Maybe the unusual sensor data showed that the birds had folded their legs and tucked them under the belly feathers? This would explain the abrupt rise in temperature and even the decrease in activity, due to the angle at which the accelerometers measure movement. This was a plausible hypothesis and it generated more questions: How common is it for shorebirds fold to their legs when flying? Which species do it? Are Great Snipes one of the species that do it? Then, delving even deeper into the mystery, why would the birds fly with folded legs? A literature search revealed very few studies on the topic. The researchers had their work cut out for them. At this point, you might be asking why does this matter? Knowledge about the way shorebirds hold their legs when flying is not something to be immediately marketed. The scientists were simply curious. It is an example of fundamental research. There is no immediate application, but who knows where it could lead? Time and again it leads to later innovations, and it often starts with a mystery. To try to solve their mystery, the researchers first put out a call for information over email and social media. They asked for photos and observations of shorebirds flying with their legs folded and any available information about species, location, date, and time. They examined online photos of flying shorebirds from the Swedish Species Observation System (www.artportalen.se). After checking nearly 10,000 photos, they found just over 1,300 that were sharp enough to determine leg position. The data in this study were gathered mainly online. Working primarily online is something many of us have been doing since the start of the current pandemic (in the best-case scenario). Scientists have lost field seasons, experiments, even jobs. Though conducted before the pandemic, this study shows that research can go on, in some capacity, using data that are already available online. [caption id="attachment_14029" align="alignnone" width="700"] Bar-tailed Godwits flying with legs folded (the one on the upper right) and outstretched. (photo: Jesse Conklin)[/caption]  The researchers’ call for information produced reports of 17 species flying with folded legs.  The behavior was most common in the long-legged Spotted and Common Redshank species Tringa erythropus and Tringa totanus. Reports came from Canada, the USA, New Zealand and five countries in Europe, suggesting that flying with legs folded is not restricted to a particular latitude or longitude. However, the authors acknowledge that it is not the complete story because they lacked feedback from large parts of the world and therefore data on many shorebird species. The 1,300 plus database photos with detectable leg position revealed at least 31 birds flying with folded legs. This more quantitative data allowed the researchers to estimate how often this behaviour occurs within a species. In Spotted Redshanks, about 11% of the photos had birds flying with legs tucked. Rates of over 1% were detected in Greenshanks Tringa nebularia, Ruffs Calidris pugnax and Common Snipe Gallinago gallinago. All of the information together showed that shorebirds fly with legs folded in most months of the year, in different age classes, alone and in flocks, and in both migratory flights and local movements. So, why do they do it? Perhaps to decrease heat loss in cold temperatures. A similar strategy is used when birds rest standing on one foot and tuck the other into the belly feathers (unipedal roosting). Earlier research has shown that the likelihood of unipedal roosting increases with decreasing temperature3. The colder it is, the more birds stand on one leg when resting. Thermoregulation is clearly one reason to fly with legs folded, but this can’t be the only reason because birds also fly with legs folded when the ambient temperature is mild. Might leg position affect flight performance? Folding the legs below the body moves the centre of gravity forwards. Whether this is a help or a hinderance might depend on how much fuel the bird is carrying. During migration, shorebirds can carry anything from no fuel stores to more than doubling their body mass with stored fat and protein. This fuel is mainly stored behind the centre of gravity, thus folding the legs could potentially balance stored fuel. Since birds carry different fuel loads, this might explain why both leg positions are found in flocks where birds are experiencing the same ambient temperatures. Could muscle fatigue be another explanation? Keeping the feet trailing during long flights is tiring. To cope, shorebirds have fatigue-resistant slow tonic and twitch fibres in their leg muscles, whereas perching bird species, which tend to fly with legs tucked, have a lower proportion of such slow fibres4. Based on muscle anatomy, it should be easier for birds that normally fly with extended legs to sometimes fly with folded legs (as seen in shorebirds) rather than the other way around. This idea remains to be tested. Now returning to the mystery, what about Great Snipes, do they fly with legs folded? Unfortunately, the authors found no evidence of this. However, Great Snipes are rarely seen and when they are seen, it is difficult to see leg posture in flight. The authors did find the behaviour in many other species, including the Common Snipe, a close relative to the Great Snipe. They therefore conclude that flying with folded legs may well occur in Great Snipes, but proof remains to be found. Although the authors did not entirely solve their mystery, they gathered a lot of previously unknown information. Their study indicates shorebirds do sometimes fly with folded legs and that reducing heat loss at low temperatures is a likely reason for this behaviour, but not the only one. Aerodynamics and leg muscle fatigue may also play a role. The research generated both new knowledge and further questions. This is the essence of fundamental research, which often lays the foundations for innovation. Examples abound, but here is a bird-related one. In the 1970s, researchers were studying retroviruses in chickens. When they found something puzzling, and started searching for answers, they were not looking to revolutionize the field of cancer genetics. Yet their discovery that the cancer-causing genes – oncogenes – in chicken retroviruses were actually derived from the host genome was a breakthrough. Oncogenes were now relevant for all animals, including humans. Later, researchers studying oncogenes in humans encountered a particular gene – HER2 – that was associated with aggressive forms of breast cancer. This gene became the target of research that eventually led to drugs like Herceptin for breast cancer and Gleevec for chronic myelogenous leukemia. For decades, different teams of researchers found mysteries and built upon the work of others to solve them. The culmination of all of these projects – which began with research on retroviruses in chickens5 – gave us life-saving drugs. Especially in our current era with so many pressing problems to solve, it is important to remember that the best way to fuel innovation is to support fundamental research. Stay curious. PDF is available for download here: https://www.waderstudygroup.org/article/13808/
  1. Lindström, A & T. Alerstam. 2020. Waders flying with folded legs – which species, when, where and why? Wader Study 127(2): 113-120.
  2. Bäckman, J., A. Andersson, L. Pedersen, S. Sjöberg, A. P. Tøttrup & T. Alerstam. 2017. Actogram analysis of free-flying migratory birds: new perspectives based on acceleration logging Journal of Comparative Physiology A203543–564. https://doi.org/10.1007/s00359-017-1165-9
  3. Ryeland, J., M.A. Weston & M.R.E. Symonds. 2019. Leg length and temperature determine the use of unipedal roosting in birds. Journal of Avian Biology 50(5): e02008. https://doi.org/10.1111/jav.020
  4. Walker, A.M. & R.A. Meyers. 2019. The anatomy and histochemistry of flight hindlimb posture in birds. II. The flexed hindlimb posture of perching birds. Journal of Anatomy 234: 668–678.
  5. Sawyers, C. L. 2019. Herceptin: A First Assault on Oncogenes that Launched a Revolution. Cell 179: 8-12. https://doi.org/10.1016/j.cell.2019.08.027
Spotlight: A Shorebird Mystery

Scientific research often begins with a mystery – something in the data that makes the researchers think – Huh? That’s funny. In this issue of Wader Study, authors Lindström and Alerstam begin their paper1 with just such a mystery. The researchers studied the 5,000–7,000 km non-stop flights that Great Snipes Gallinago media make during migration from central Sweden to equatorial Africa (and back). To do this, they attached tiny sensors (called mini-multisensory accelerometers) to the