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National Geographic magazine is publishing a series of bird-related feature articles in 2018, in honor of 'The Year of the Bird'. One in the March issue entitled "The Epic Journeys of Migratory Birds" is about bird migration and focuses on Bar-tailed Godwits, and features Jan van Gils, the Alaska USGS people, Jesse Conklin, and several other migration scientists that you will know! visit theThe Epic Journeys of Migratory Birds page on the National Geographic website:   Featured image: Bar-tailed godwits in the mud at the Heathcote and Avon Estuary in Christchurch, New Zealand. ©Jonathan Harrod, Minden Pictures for the National Geographic.
Bar-tailed Godwits in the March issue of the National Geographic Magazine

National Geographic magazine is publishing a series of bird-related feature articles in 2018, in honor of 'The Year of the Bird'. One in the March issue entitled "The Epic Journeys of Migratory Birds" is about bird migration and focuses on Bar-tailed Godwits, and features Jan van Gils, the Alaska USGS people, Jesse Conklin, and several other migration scientists that you will know! visit theThe Epic Journeys of Migratory Birds page on the National Geographic website:   Featured image:

If you’re lucky, when you are expecting a baby, you have access to pre-and post-natal care. In humans, this refers to physician or midwifery support before and after birth, but also to having the space and time to eat and rest well. Migratory shorebirds also need safe places to eat and rest pre- and post-breeding. In this issue of Wader Study, two articles describe stopover sites that provide this space en route to and away from breeding grounds. These articles also show what studying birds as they pass through these sites can tell us about other parts of the annual cycle, including breeding. Let’s begin with the post-breeding period. In both humans and birds, this is the time that seems to get the least attention. Many new parents find themselves on their own with their new baby in the days after birth, and similarly not much is known about the stopover sites birds use post-breeding. I was lucky to have had a child in the Netherlands where they have a wonderful thing called kramzorg1. For a week after I gave birth, a kraamverzorgster came to my home and helped with everything from teaching me to breastfeed to washing the dishes and making peanut butter sandwiches (which was all I wanted). It was revolutionary for me to discover this kind of care (and the need for it) around a topic I thought I knew well – having a baby. In much the same way Lyons and colleagues write about a well-studied species, but shine light on a period of the annual cycle that hasn’t been well studied – post-breeding stopover. They report on a mark-recapture/resight approach to study migration and stopover ecology in the Red Knot, Calidris canutus rufa, at Mingan Archipelago National Park Reserve in eastern Canada2. [caption id="attachment_10541" align="alignnone" width="960"] The post-breeding stopover site at Mingan Archipelago National Park Reserve, Quebec, Canada. Photo: Yves Aubry. Inset: A rufa Red Knot in non-breeding plumage. Photo: Patricia González.[/caption] The researchers’ first task was to collect the mark-resight data. They conducted surveys on four limestone islands (Niapiskau, Quarry, Grand-Île, and Nue de Mingan) at the western end of the Mingan Archipelago Reserve between 11 July and 3 September 2008. Between 9:00 in the morning and 3:00 in the afternoon they looked for knots, counted their numbers, and noted the proportion with uniquely engraved leg flags (marked birds). They detected five-hundred thirty-five (535) adults with leg flags. Most of these birds had received their flags as part of prior work at other locations along the flyway in Canada, the United States, Brazil, Argentina or Chile. Blood samples had been taken when the birds were captured and marked. These samples were used in molecular techniques to determine the sex of the birds. Then the 535 observations were converted into encounter histories, one for each bird, and analyzed mathematically using a Jolly-Seber (JS) model. The study had four goals: (1) use mathematical models and mark-resight data to describe when the birds arrive, how long they stay, and when they depart; (2) use data on when males, females and young arrive to infer how well the past breeding season went; (3) estimate how many birds use the sight, taking into account that birds pass through and that not all birds will be counted; (4) formalize the method for using quantitative mark-resight data to understand migration and stopover ecology in migratory birds. Using their field observations and the mathematical model, the authors estimated approximately 9,500 birds (8,355–10,710) used the stopover site at the Mingan Archipelago in 2008. The birds stayed on average about 11 days with a minimum-length-of-stay (MINLOS) about half that. The 535 marked birds seen during the field season represented approximately 64% of the total number of marked birds, or how many would have been seen if every marked bird could have been seen. Mathematically, the model that best explained the data with the fewest variables (the most parsimonious model) assumed that this resighting probability stayed constant. On the other hand, the probability of birds arriving, and how long they stayed, was not constant. Adult birds arrived in Mingan in two distinct waves. The first group arrived in mid-July and were mainly females who had likely nested successfully, and males and females whose nests failed. The second group arrived from August 8th to 11th and were mainly juvenile birds and males that nested successfully (and thus stayed longer to care for young). Though seemingly a simple description of timing, the authors point out that these results are important because the timing and type of birds arriving in Mingan tell us something about the success of the prior breeding season. In 2008, a large fraction of the stopover population arrived late in the season and most were juveniles and males. This suggests successful breeding. Being able to infer something about the breeding season from 1700 km away, makes the modelling described in this article a powerful tool, especially for species whose breeding sites are not easily accessible and whose nests are not easy to find. Sticking with Red Knots, but switching to subspecies C. c. roselaari, Buchanan and colleagues report on between-year variation in stopover timing at Grays Harbor, Washington, USA3. Here the focus is on spring migration and the pre-breeding period. In knots, more is known about pre- than post-breeding stopover sites (the famous Delaware Bay for C. c. rufa comes to mind); however, less is known about stopover sites for C. c. roselaari, whose flyway spans the Pacific side of North America4. Therefore, the authors took the opportunity to synthesize data in two previous surveys of Grays Harbor, conducted in 2009 and 2010, with data collected more recently in 2016. [caption id="attachment_10542" align="alignnone" width="960"] The post-breeding stopover site at Grays Harbor, Washington, USA. Photo: Joseph Buchanan. Inset: A roselaari Red Knot in breeding plumage. Photo: Tom Rowley.[/caption] Grays Harbor is a large estuary on the Pacific coast that is dominated by extensive flats at the confluence of seven rivers. Knots use areas in these mudflats that are too far from shore to be visible, particularly in the second half of the migration period, so researchers have to get creative to see the flocks. In this case they used airboats. From these boats, they estimated knot numbers by scanning the flocks and counting in increments of 20, 50 or 100 birds (depending on the size of the flock). The researchers found that knots passed through the area later in 2016 than in 2009 and 2010. Though the study was not designed to determine the cause of this variation in timing, the authors suspect that the later passage in 2016 was influenced by conditions in Mexico because knots appear to fly directly from wintering areas in Mexico to coastal Washington during spring4. The authors mention possible causes including variation in numbers of predators, such as Peregrine Falcons Falco peregrinus, or differences in the timing of food resources in Mexico. Whether human or bird, having a safe and resource-rich place to rest and eat is important for reproduction in both the pre- and post-natal periods. Both of these papers remind us of the importance of stopover sites used by migratory shorebirds en route to and from breeding areas, and both papers remind us that these sites can provide a treasure trove of information, even on a well-studied species.
  1. For those unfamiliar with the Dutch and Belgian kraamzorg system see: https://en.wikipedia.org/wiki/Kraamzorg and also https://www.babble.com/parenting/the-incredible-post-birth-service-all-dutch-women-receive/
  2. Lyons, J. E., A. J. Baker, P. M. González, Y. Aubry, C. Buidin & Y. Rochepault. 2017. Migration ecology and stopover population size of Red Knots (Calidris canutus rufa) at Mingan Archipelago after exiting the breeding grounds. Wader Study 124(3): 197-205.
  3. Buchanan, J. B., L. J. Salzer & V. Loverti. 2017. Between-year variation in the timing of peak passage of spring migrant Red Knots at Grays Harbor, Washington, USA Wader Study 124(3): 238-240.
  4. Carmona, R., N. Arce, V. Ayala, A. Hernández-Alvarez, J.B. Buchanan, L.J. Salzer, P.S. Tomkovich, J.A. Johnson, R.E. Gill, Jr., B. McCaffery & J. Lyons. 2013. Red Knot (Calidris canutus roselaari) migration connectivity, abundance and nonbreeding distribution along the Pacific coast of the Americas. Wader Study Group Bulletin 120: 168-180.
PDF is available here.
Spotlight: Stopovers as “pre- and post-natal support” for migrants

If you’re lucky, when you are expecting a baby, you have access to pre-and post-natal care. In humans, this refers to physician or midwifery support before and after birth, but also to having the space and time to eat and rest well. Migratory shorebirds also need safe places to eat and rest pre- and post-breeding. In this issue of Wader Study, two articles describe stopover sites that provide this space en route to and away from breeding grounds. These articles also show what studying birds as

IWSG Small Projects Grants

Since 2016, the International Wader Study Group have annually been funding small projects through the newly established IWSG Small Projects Grants. The aim is 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 pounds sterling per project). In the below link you can find a description of criteria and the application form. The IWSG Executive Committee has appointed an evaluation committee that will judge the applications, and decide which project will be awarded. Hurry up!, applications should be submitted by December 1th of each year, and a decision will be made before 1st of May. Application form IWSG Small Project Grants Call. [caption id="attachment_8912" align="aligncenter" width="330"] Last year, the 2016 IWSG Small Project Grants was attributed to Glenda D. Hevia to support his reaserach about the impact of human activities on Two-Banded Plovers (Charadrius falklandicus) breeding at beaches in Northern Patagonia, Argentina. You can follow the study at this ResearchGate Project page!: https://www.researchgate.net/project/Effects-of-human-activities-on-the-Two-banded-Plover-Charadrius-falklandicus-breeding-population-in-northern-Chubut-Patagonia-Argentina Photo: ©Darío Podestá.[/caption]
Only two days left to apply for the 2017 IWSG Small Projects Grants!

IWSG Small Projects Grants Since 2016, the International Wader Study Group have annually been funding small projects through the newly established IWSG Small Projects Grants. The aim is 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

The “Marais Breton” (46.987867, -1.960771) is one of the last strongholds for breeding Black-tailed Godwit Limosa limosa limosa  in France. The area supports up to 60% of the French population (~150-170 pairs). Whilst the importance of other sites in France continues to decrease, the population in the Marais Breton remains stable and even increasing mainly due to conservation action by The Ligue pour la Protection des Oiseaux LPO Vendée (local delegation of the Birdlife partner in France). [caption id="attachment_10401" align="aligncenter" width="330"] The Marais Breton on the French Atlantic coast is the last bastion of breeding Black-tailed godwit in France. Picture: © Philippe Briffaud.[/caption] For several years now, LPO Vendée has been working with young livestock farmers to improve farming practices - extensive, organic, pesticide-free farming - that provide environmental benefits, especially on wetlands. These wildlife-friendly farmers (“Paysans de nature”), for whom protecting biodiversity is equally important as producing better agricultural products, consider the space left for wildlife on their farms. For instance, several of the farmers deliberately flooded meadows in spring to make land suitable for the settlement and breeding success of waders and waterfowl (including Black-winged Stilt, Black-tailed Godwit, Common Redshank, Ruff, Common Snipe, Northern Lapwing, Northern Shoveler, Pintail, Eurasian Wigeon, Teal and Garganey). In addition to land management, LPO Vendée also acts in an advisory role to provide assistance and support to these farmers for better integration of biodiversity and farming. The project has been successful to date, with farmers also involved in biological monitoring, as well as public outreach activities. They have therefore become real ambassadors of nature conservation and volunteer wardens of a new kind of nature reserve. In this context, along with 2 other organizations from the “Marais Breton” and 3 young farmers, LPO Vendée is purchasing 200 acres of flood meadows close to the current breeding area of the population of Black-tailed Godwit. This vital work has the potential to extend the existing breeding habitat by 35%, but will not be possible without the generous support of the public so the LPO Vendée has launched a crowdfunding campaign on the French platform Ulule. The campaign has already raised €10,000 but their target is €15,000 euros to extend this conservation work.

You can learn more and contribute to the campaign here: https://fr.ulule.com/ferme-cochets/

If you wish to contribute by bank transfer, please contact Perrine Dulac at marais-breton@lpo.fr. For more information about the project you can visit: https://www.bargeaqueuenoire.org/ & www.paysansdenature.fr LPO Vendée will be very happy to welcome IWSG members wishing to visit the area!   [caption id="attachment_10406" align="aligncenter" width="330"] Visit the dedicated website on the monitoring and conservation program of Black-tailed Godwit in Vendée & Pays de La Loire. The website compiled information on the species, surveys & conservation actions carried out in the area. It hosts also an online database for recoveries of colour-ringed Black-tailed Godwit, where observers can enter their observation data and consult the bird's life history. https://www.bargeaqueuenoire.org[/caption]   Featured image: Black-tailed Godwit Limosa limosa limosa ©Rémi Bontemps.  
Buying meadows for Black-tailed godwit conservation in France!

The “Marais Breton” (46.987867, -1.960771) is one of the last strongholds for breeding Black-tailed Godwit Limosa limosa limosa  in France. The area supports up to 60% of the French population (~150-170 pairs). Whilst the importance of other sites in France continues to decrease, the population in the Marais Breton remains stable and even increasing mainly due to conservation action by The Ligue pour la Protection des Oiseaux LPO Vendée (local delegation of the Birdlife partner in France).

  • 1,207 hours of intense preparation from all organizers
  • 720 liters of beer drunk ad libitum throughout the whole conference
  • 404 Euros gained for IWSG via silent auction
  • 202 registered participants from 28 countries worldwide
  • 101 regular contributions (70 oral presentations, 31 posters)
  • 32 new IWSG members gained via Prague conference
  • 6 excellent plenary talks
  • 4 various excursions (unexpectedly nearly without waders)
  • 3 productive workshops
  • 1 friendly, vibrant and inspiring atmosphere in Prague created by all participants
This could be a short summary of our successful meeting in Prague. However a few more things deserve to be highlighted, especially those introduced for the first time in Prague. Nearly all presentations were videorecorded to allow you to catch up with parallel sessions, to let remote members to follow the conference and to give a feedback to presenters about their performance. All IWSG members can watch these recordings via this link: http://www.waderstudygroup.org/article/10362/ The last videos will be added soon and you can find there also contributions taped remotely in Brazil or Bangladesh and sent in advance from participants who in the end could not make it personally to Prague. Furthermore, we had your movies about waders being broadcasted during breakfasts, shorebird voices recognition contest, roasted invasive sika deer, superior Meopta optics exhibition, great drawings capturing many presentations from Ysbrand Galama, frisbee and discgolf sessions. Let’s see which features will launch a new tradition!   Once again, I would like to thank all participants for contributing to our pleasant Prague conference. It was the great pleasure for us to host you in Prague! Vojta Kubelka (on the behalf of the organizing team)    
Prague International Wader Study Group Conference retrospect

1,207 hours of intense preparation from all organizers 720 liters of beer drunk ad libitum throughout the whole conference 404 Euros gained for IWSG via silent auction 202 registered participants from 28 countries worldwide 101 regular contributions (70 oral presentations, 31 posters) 32 new IWSG members gained via Prague conference 6 excellent plenary talks 4 various excursions (unexpectedly nearly without waders) 3 productive workshops 1 friendly, vibrant and inspiring atmosphere in Prague

Simon Feys steps down as Colour-mark Sightings Officer

Simon was responsible for the IWSG sightings mailbox since March 2013. During his time as sightings officer he has dealt with about 3,000 sightings within the East Atlantic Flyway and elsewhere in Europe, distributing these sightings out to the network of species experts and then recording the outcome of the sightings as either success or failure. The sightings officer is an important role within the IWSG, helping observers trace project leaders of colour-marking projects that they have not been able to track down themselves. It can also be a frustrating job if people do not answer e-mails – which happens far too often. The position of the sightings officer is not a position within ExCo and as Simon did not come to the Wader Study Group Annual Conferences it is probable that not very many of you have actually met him, but he was always there working for the IWSG. We thank him for all his hard work over these years!   [caption id="attachment_10345" align="aligncenter" width="330"] Since 2013, Simon Feys has worked behind the scene as IWSG colour mark sightings officer. We are sincerely grateful to him for the work accomplished during his mandate.[/caption]  
Goodbye to our colour mark sightings officer Simon Feys

Simon Feys steps down as Colour-mark Sightings Officer Simon was responsible for the IWSG sightings mailbox since March 2013. During his time as sightings officer he has dealt with about 3,000 sightings within the East Atlantic Flyway and elsewhere in Europe, distributing these sightings out to the network of species experts and then recording the outcome of the sightings as either success or failure. The sightings officer is an important role within the IWSG, helping observers trace project

For the second year running, the International Wader Study Group will be awarding small projects with small grants from our IWSG Small Projects Grants prorgam. Deadline for submission of projects for the 2017 grant (field work 2017/2018) is 1 December 2017. Read more here: www.waderstudygroup.org/projects/iwsg-small-projects-grants-apply-now/. We look forward to your application! [caption id="attachment_8912" align="alignnone" width="330"] ©Darío Podestá. Lasy years winner, Glenda D. Hevia, collecting data from Two-Banded Plover nests during fieldwork at Península Valdés, Patagonia Argentina.[/caption]  
IWSG Small Projects Grants: Call 2017 is now open

For the second year running, the International Wader Study Group will be awarding small projects with small grants from our IWSG Small Projects Grants prorgam. Deadline for submission of projects for the 2017 grant (field work 2017/2018) is 1 December 2017. Read more here: www.waderstudygroup.org/projects/iwsg-small-projects-grants-apply-now/. We look forward to your application!  

The 4th WCWW will take place on the 4th and 5th November 2017.

"Make a note in your diary to join in the fun!

To take part is as simple as A,B,C.

A. Go out and see waders/shorebirds wherever you are in the world. B. Send us an email telling us what you have seen and where. C. Look for your birds on the species list and your name on the roll of honour on this website. You will also receive a Wader Quest The Newsletter WCWW e-newsletter special to your email address with all the results, lists and the roll of honour. 

It is that easy; no registration required just good old-fashioned bird watching... Oh! And an email. waderquest@gmail.com"

  Wader Quest is a charity that aims to involve local groups and communities in Wader conservation. Read more about Wader Conservation World Watch: here [caption id="attachment_10164" align="aligncenter" width="534"] 2016 results of WCWW: 125 species reported by 245 observers of 38 countries on 6 continents in all 9 flyways. ©Wader Quest[/caption]
Save the date!: 4-5 November 2017 – 4th Wader Conservation World Watch

The 4th WCWW will take place on the 4th and 5th November 2017. "Make a note in your diary to join in the fun! To take part is as simple as A,B,C. A. Go out and see waders/shorebirds wherever you are in the world. B. Send us an email telling us what you have seen and where. C. Look for your birds on the species list and your name on the roll of honour on this website. You will also receive a Wader Quest The Newsletter WCWW e-newsletter special to your email address with all the results, lists

Yahkat Barshep highlights the inadvertent protection/conservation of waterbirds and their habitats, through traditional religious beliefs and ancestral practices of the African people, with particular references to Nigeria. Read more here: Wader Study Article in issue 124-2. Illustration by Clara Cassell: a sketch of  a scene depicting one of the festivals mentioned in the article. Feature photo: Jeroen Reneerkens    
Perspective: African spirituality and African nature

Yahkat Barshep highlights the inadvertent protection/conservation of waterbirds and their habitats, through traditional religious beliefs and ancestral practices of the African people, with particular references to Nigeria. Read more here: Wader Study Article in issue 124-2. Illustration by Clara Cassell: a sketch of  a scene depicting one of the festivals mentioned in the article. Feature photo: Jeroen Reneerkens    

It’s a bird with a “spoon” for a bill, but though this bird does use its spoon-bill for eating, we’ll learn in a paper by Kelly and colleagues1 in this issue of Wader Study that this bird does not use its bill like a spoon. The Spoon-billed Sandpiper is a small wader that breeds in NE Russia and winters in SE Asia. It is one of the world’s best known waders, despite being one of the world’s rarest birds, but it would be pretty plain if not for its distinctive spatulate bill. It is this bill that fascinates birders and bird scientists alike, because the Spoon-billed Sandpiper is the only wader species in the world to have evolved a spoon-shaped bill – and that raises the tantalizing question: Why? Kelly, Zöckler, Scampion and Syroechkovskiy tackle this mystery through an impressive set of observations collected through all stages of the Spoon-billed Sandpiper’s life cycle. They synthesize these observations into six feeding techniques that explain how these waders use their remarkable bills. Then they use these newly described feeding behaviors to discuss how and why the spoon-shaped bill might have evolved. To begin, the researchers present a detailed description of the Spoon-billed Sandpiper’s extraordinary bill. Upon close inspection, it is rather more like a spatula than a spoon. Its tip is expanded sideways into two triangles with rounded outer edges that slope downwards slightly. [caption id="attachment_10078" align="alignnone" width="700"] Spoon-billed Sandpiper on its Arctic breeding grounds in Chukotka, Meinopylgino, Russia 3 July 2012 (photo: B. Scampion)[/caption] Though this clearly looks very different from other Calidris sandpiper bills from the outside, the authors point out that when the bird opens its bill it is possible to see the outline of the basic sandpiper bill within (see their Fig. 1). However, the bill of Spoon-billed Sandpiper also differs from other sandpipers in several important respects: (1) the bill is expanded at the base as well as the tip, giving the birds a broader tongue, (2) there are more epidermal papillae (which help to keep food moving backward while the tongue is moving in both directions), (3) there is a larger than usual concentration of Herbst corpuscles (nerve endings that may help birds to sense prey under wet sand or soil2) at the bill tip. These intriguing differences likely relate to how the bill is used. So how do Spoon-billed Sandpipers use their bill for feeding? Answering this question took years of careful observation, both at breeding areas in Russia and at non-breeding areas in Bangladesh, Thailand, Myanmar and China. During this extensive fieldwork spanning from 2003 to 2017, the researchers also collected more than 1000 photos and videos. Using this treasure trove of field observations, the authors first define behavioural elements (which are not in themselves feeding techniques): Concertinaing, Grandstanding, Pirouetting, Jumpback and Transitting (the paper provides detailed descriptions in Table 1 and photo examples of birds performing these behaviours). The authors then use these fascinating behavioural elements to describe six specific feeding techniques (nicely summarized in their Table 2):
  1. Selectively pecking: Steady forward pecking in mud or shallow water.
  2. Sweep-stitching: A stitching movement along the axis of the bill combined with a sideways motion at the highest point in the “stitch”. This technique is unique to Spoon-billed Sandpipers. Other Calidrids use similar techniques, but no other creates the impression of sideways sweeping.
  3. Burst-stitching: Similar to sweep-stitching, but with less side to side movement.
  4. Spear-hunting or ‘hammering’: A technique in which the bird grandstands and then ‘hammers’ their bill into the water or substrate.
  5.  Stabbing: Like burst-stitching, but more forceful and with the bill closed when it is inserted into the substrate.
  6. Hoovering: A technique where only the bill tip is inserted into the substrate and the bird makes very rapid but shallow stitching movements creating the impression of hoovering/vacuuming the substrate.
The authors then discuss these techniques within the context of previously published hypotheses of how the Spoon-billed Sandpiper’s bill might be used for food intake like a shovel, a hoe, a mousetrap and a biofilm grazer. Then they develop their own metaphors for how the birds use their spoon-shaped bill like a hammer, a filter and a microphone. The hammer. A hammer is a tool with a heavy head used for jobs like breaking things or driving objects into a surface. Spoon-billed sandpipers use their bill like a hammer to forcefully immobilize prey while spear-hunting or ‘hammering’ and also during stabbing. But other species do this too and the authors argue that there is no firm link between the spoon-billed structure and better success in direct hits of larger prey. The Filter. A filter is a porous device that serves to remove solid particles from a liquid (or gas) that is passed through it. The bill may act like a filter to harvest small food items, especially when feeding on biofilm. The idea, proposed by Danny Rogers in 2007, is that the sandpipers use their bill like a Dutch hoe (a garden tool with a blade that is similar in shape to the bill) to liquefy the substrate and immobilizes prey. Prey are then filtered from the liquid using the epidermal papillae and the large tongue as a pump. The authors conclude that this hypothesis has traction and might have contributed to the evolution of the bill shape, but perhaps in combination with the bill first being used as a microphone (sensor) to detect prey. The Microphone. A sound microphone detects changes in pressure (sound waves) and turns them into something else (electrical signals), these signals then move to an amplifier or a recording device. The Spoon-billed Sandpiper’s bill does not detect sound waves, but rather it acts as a microphone by acting as a sensor to detect changes in pressure. The Herbst corpuscles are used to detect pressure gradients at various locations on the bill surface. The bird then detects obstructing objects (prey) that have caused a disturbance in this pressure map. The fact that Spoon-billed Sandpipers have much higher numbers of Herbst corpuscles than related sandpiper species is circumstantial evidence that pressure sensing might have been involved in the evolution of their bill shape. In addition, the part of the bill containing the Herbst corpuscles is thicker than the rest of the bill, which might enhance the pulse and amplify the signal. Also the canted angle of the front edges and the soft corners of the bill might reduce turbulence. Examined in this context, feeding techniques such as pecking, stitching and stabbing could be used to generate a disturbance in the pressure field. This disturbance would make it possible for birds to detect prey based on directional cues enhanced by the laterally expanded bill. Hoovering might also be a method of pressure sensing near surface level with lighter impact pecks generating smaller pressure waves to detect items at close range. Using the bill like a pressure sensor might be particularly useful in muddy substrates where the technique would allow effective spear-hunting without the bird needing to visually see the prey. The authors conclude that the pressure-sensing hypothesis (the bill as a microphone) seems to be the most compelling as an explanation for how small but incremental lateral enlargements of the bill might have provided a selective advantage. Using their bills like a microphone, birds with broader bills might have possessed greater ability to detect and capture prey, enjoyed better survival, and produced more chicks with spoon-bills. Of course all of these arguments make the reasonable assumption that the bill shape is a specific adaptation for feeding. The authors do not discuss the possibility that the Spoon-bill Sandpiper’s bill might have some other adaptive value, such as for thermoregulation3. Or that the bill might not be adaptive at all. Odd things happen in nature all the time. Take for example an astonishingly long Eurasian Oystercatcher bill also described in this issue of Wader Study4. Is this adaptive? What would happen if females started to find this male incredibly attractive and he produced many offspring? In a recent book5, Richard Prum –building on Darwin’s ideas about mate choice – proposed that some traits might have nothing to do with functionality, but rather evolved through pure aesthetics. If the Spoon-billed Sandpiper’s bill serves only to attract mates then it might even contribute to the species’ small population size; sexual selection and extinction risk can be related6. Another possibility is that the bill has no real benefit, but is not sufficiently maladaptive to be removed by natural selection. Such evolutionary oddities have the greatest chance of arising and persisting in small populations, which may explain other traits of unclear function, such as the equally peculiar apparatus of the Wrybill. The truth is we just don’t know, but Kelly and colleagues give us much to think about.
  1. Kelly, C., C. Zöckler, B. Scampion & E. E. Syroechkovskiy. 2017. Hammer, Filter or Microphone – How does the Spoon-billed Sandpiper Calidris pygmaea use its bill to feed? Wader Study 124(2): 99–104.
  2. Piersma, T., R. van Aelst, K. Kurk, H. Berkhoudt, & L. R. M. Maas, Leo R. M. 1998. A New Pressure Sensory Mechanism for Prey Detection in Birds: The Use of Principles of Seabed Dynamics? Proceedings: Biological Sciences265(1404): 1377–1383.
  3. Tattersall, G.J., B. Arnaout & M.R. Symonds. 2017. The evolution of the avian bill as a thermoregulatory organ. Biological Reviews 92: 1630–1656.
  4. Cooney T. 2017. Extraordinary bill abnormality in a Eurasian Oystercatcher. Wader Study 124(1): 155–156.
  5. Prum, R. O. 2017. The Evolution of Beauty: How Darwin’s forgotten theory of mate choice shapes the animal world - and us. New York: Doubleday.
  6. Kokko, H., & R. Brooks. 2003. Sexy to die for? Sexual selection and the risk of extinction. Annales Zoologici Fennici 40: 207–219.
PDF is available here.
Spotlight: Not a spoon, but maybe a hammer, filter, or microphone

It’s a bird with a “spoon” for a bill, but though this bird does use its spoon-bill for eating, we’ll learn in a paper by Kelly and colleagues1 in this issue of Wader Study that this bird does not use its bill like a spoon. The Spoon-billed Sandpiper is a small wader that breeds in NE Russia and winters in SE Asia. It is one of the world’s best known waders, despite being one of the world’s rarest birds, but it would be pretty plain if not for its distinctive spatulate bill. It is