This blog tells a few stories about individual colour-ringed Black-tailed Godwits and the ‘godwiteers’ who watch them on the estuaries of the east coast of England. They’re part of an international network of 2000 birdwatchers, contributing to some fascinating science.
The dots on graphs within scientific papers hide fascinating stories about individual birds. With the help of a small number of colour-ring readers, here’s an opportunity to eschew the statistics and to focus on a few of the Black-tailed Godwits that have been recruited to help answer scientific questions. The next colour-ringed godwit that you spot may have been hundreds of miles away just 24 hours ago or could break the longevity record for the species of 25 years. At the end of this blog there’s a list of 18 published papers, most of which could not have been written without the help of colour-ring observers – our ‘godwiteers’.
Over the last two decades, Dudley and Carol Hird have seen over 500 individual colour-ringed Black-tailed Godwits in Kent, Graham Catley has witnessed a huge expansion of the wintering flock on the Humber, David and Pat Wileman have co-ordinated daily counts and sightings at Cley, while Simon & Pat Cox, Ed Keeble and Mark Nowers have collected data in Essex – and turned the Mistley flock on the Stour estuary into an open-air migration display for the public.
There has been a fantastic rise in the number of Black-tailed Godwits on the east coast of England since the 1990s. Work led by Prof Jennifer Gill and published in Nature in 2001 showed that this expansion was an example of a buffer effect, with newly colonised winter sites being of lower quality than sites further south in the range. As you will read, winter flocks rarely experience the bitingly-cold weather that they did twenty years ago and birds have learned to take advantage of feeding opportunities on grassland, particularly on the Ouse Washes. Life on the east coast may well now be easier than it once was but it is still a lot colder than the sunny conditions experienced by godwits wintering in Portugal, for instance, as shown in this paper in Ecology.
Graham Catley on the Humber estuary
Graham has witnessed a huge expansion in the number of Black-tailed Godwits on the Humber. Many of the birds that are seen on this estuary in autumn and early winter turn up at Welney, on the Ouse Washes, in the period February through to April, where they moult into their summer finery prior to a migration of more than 1500 km to Iceland.
My old notebooks tell me that I saw 11 Black-tailed Godwits at North Killingholme Haven pits on August 20th 1969 but it was autumn 1989 before there were more than 50 recorded. Little did we know at that time just how things would change over the next 27 years. In autumn 1995 the peak count at North Killingholme was 178 on August 28th but significantly on that date I saw a bird with colour rings. Subsequent enquiries revealed that it had been ringed on the Eden Estuary in Fife in 1993 – and a second bird was seen the following week from the same scheme. In 1996 new birds were seen from a scheme in the Wash and my first contact was made with Jenny Gill, who has furnished me with detailed ringing and recovery information on what are now over 300 different birds seen on the Humber since those initial sightings. Autumn passage can see a high tide roost of up to 6400 birds at North Killingholme (probably about 10% of the Icelandic population) but seeing leg rings can be problematic, as birds often stand in deep water and flocks are spooked by local Sparrowhawks and Peregrines.
The Humber Estuary started to hold wintering birds in the late 1980’s and now there are up to 2500 birds from November through to February. Checking colour-ringed birds has shown us that there are complex movements of birds around the estuary but also around Europe. Some of our autumn birds appear for quite short periods before moving on south while others seem to move to the Wash and then come back up to the Humber for the winter. Many wintering birds move south to the Ouse Washes in late winter and early spring, before heading off for Iceland, while others have been shown to move cross-country to Lancashire and Ireland. We’ve seen individuals from schemes in Portugal, France, Ireland, Scotland, Suffolk, Hampshire and of course the Wash and Iceland. It is always great to catch up with a bird you have not encountered for a few years and bumping into individuals with new types of rings or combinations begs the question – is it from a new scheme or have they run out of combinations?
In practical conservation terms, observing the colour-ringed godwits on the Humber has provided a large amount of information on the birds’ favoured roosting and feeding areas and how different individuals use the estuary during the course of the year. It also adds a little spice to a day’s birdwatching – trying to get an accurate count of a large and mobile flock of charismatic waders, identifying old friends and new acquaintances and finding out what other exotic and not-so-thrilling parts of the continent they have visited on their phenomenal migrations.
David & Pat Wileman at Cley, Norfolk
Working our way south, the next site with a long-run of colour-ring sightings is Cley, on the North Norfolk coast. Not only do David & Pat Wileman collect daily counts and observations, they also record individual moult patterns, as birds change in and out of their summer plumage.
There’s already a blog about the Black-tailed Godwits of Cley here.
Ed Keeble on the Stour estuary, Essex
Ed Keeble is one of an enthusiastic team of colour-ring readers on the Stour. He combines observations with photography and evocative art-work. The Stour held large flocks of waders long before sites such as the Wash and Humber, with birds using the estuary in the autumn, winter and spring.
I’m lucky enough to have have been born and bred on a farm on the banks of the Stour, so my earliest birding memories are of watching godwits roosting on our fields in the mid -1970s, through a leather-bound brass telescope . We were very proud of the godwits because, at that time, the Stour flock was one of only two in the UK that regularly approached 1000. With no colour-rings we knew very little about them. The godwits used to endure ferocious winter weather in those days. I’ve even seen them “legless”- flying with their legs folded forward into their breast feathers to conserve heat.
Fast forward to the present day and I am still birding intensively on the Stour, but with improved optics. I had noticed colour-rings on the godwits for many years but had assumed that there were some scientists somewhere who busied themselves reading them and therefore that there was nothing to report. The moment of revelation for me was a talk by Jenny Gill, when I was surprised to hear that the scheme was dependent on public sightings and that we were positively encouraged to pester her, Pete Potts and other colleagues with sightings!
One of the most rewarding aspects of reading colour-rings on the Stour at Mistley is how common it is to find a casual birdwatcher who has seen a ringed godwit, has sent the sighting in and been absolutely thrilled to get an email back with details. I’ve been told countless times with great pride that “I got an email back from a professor and my godwit came from Iceland.” There’s no doubt that one of the things which sets this scheme apart is the prompt response to sightings and the willingness to spend time unravelling confused and inconsistent ring-readings from the likes of me. This must take ages, but generates a great deal of goodwill.
One of my favourite regulars is a bird I know as the Yob (Yellow Orange – Blue over Blue), who was ringed by an old University friend in Scotland and sent down south for my entertainment. I’m still very much in my apprenticeship when it comes to the dark arts of colour-ring reading, but beginning to learn the difference between faded red and orange, and that things which look orange or yellow may in fact be stained white.
One of the most fascinating local insights from the colour-ring returns is the number of godwits using the Stour. Based on counts of flocks alone, we know that we have about 1,000 wintering in a normal season. But, with over 50 colour-ringed individuals per year, we have learned that there is a high degree of turnover and that the river is probably used by more than 3,000 birds, including those stopping over in the autumn on the way to France, Portugal or Spain. We also get periodic influxes of 1000 birds or more when the Ouse Washes flood in the winter. So, whilst we may not offer top-grade wintering habitat (not enough wet meadows), we are a very much a hub for godwits on the move.
Mark Nowers on the Stour estuary, Essex
Mark is one of many UK-based colour-ring readers to have followed the Black-tailed Godwits to Iceland. He happily shares his love of the birds with the many promenade-walkers, birdwatchers and swan-feeders at Mistley, engaging them with stories of the travels of ringed individuals – a bit like the Ancient Mariner, who ‘stoppeth one of three’.
Black-tailed Godwits have taken over my ornithological life since moving to work and live around the Stour Estuary in 2002. It was obvious from very early on that dedicated people were spending a great deal of time and effort ringing these birds and I felt honour-bound to let them know what I was seeing.
The platform for watching Godwits is Mistley, which is so good that the RSPB ran engagement events there for several years. Mistley is a popular promenade so, as well as people with a specific interest turning up, we have also collared passers-by who showed the merest hint of interest. It only took a few moments, having begun to explain the godwits’ migration story, for them to realise that it was worth their while stopping. We were able to crystallise things with the story of “Billy the Boomerang” (he keeps coming back!) – or LY-YW to his ringing friends. Almost without fail, every autumn and spring he reappears on the Stour Estuary; between times he spends the mid-winter period with Dudley & Carol Hird in Kent.
In 2004, I spent a week in Iceland with Pete Potts and a godwit ringing and resighting team. On the 20th April, one of the birds seen was our friend “Billy” from Mistley. Four years later, in 2008, I saw ‘Billy’ on 14th April at Mistley and he was seen by Jenny Gill and Graham Appleton at Eyrarbakki, on the south coast of Iceland, four days later. His arrival was described in a live broadcast by Graham for the World on the Move BBC radio series. Billy was ringed as an adult on The Wash in 1998, so being at least two years old at the time of ringing, he is currently 19 and still going strong. I know that, among the godwit ringing community, this is quite a regular occurrence but to the wider public, when you tell the story of the very same bird that you have seen in two different countries, the look of disbelief and amazement says it all.
Simon & Pat Cox on many Essex estuaries
As a ringer with some 55 years of experience, Simon Cox realises just how valuable each report of a ringed bird can turn out to be. Working with his wife, Pat, makes it significantly easier to collect data from big flocks of birds.The Essex coast is a very convenient base for watching Black-tailed Godwits, as our estuaries hold some 4,000 to 5,000 birds in winter (out of an estimated total of only 50,000 Islandica birds – Bird Study, 2005) and higher numbers during peak spring and autumn passage. The Stour, Colne and Blackwater estuaries have been my principal ‘godwit sites’ and I have to date recorded over 300 colour-ringed individuals, with just a few at more distant locations on my various travels, usually accompanied by my wife Pat, who has been very helpful in spotting ringed birds, especially when we have been confronted by a large flock all feeding actively in various depths of water! We sometimes take turns in keeping a ‘scope’ fixed on those frustrating birds that stand on one leg so that the full colour combination is only partly visible!
We find the movements of individuals fascinating, especially when the precise timing of the movements can be demonstrated:
GO-OfW Green orange – orange-flag white was ringed in France near La Rochelle on 23/09/09 and had been seen on 30 more occasions, twice in Iceland and the remainder in France before I saw it in Alresford Creek on 27/07/14. Vincent Lelong kindly emailed me to say it was back in France the following day.
WO-L/W I recall Jenny Gill asking me the time of my sighting of white orange – lime over white in Alresford Creek on 22/09/05. It transpired that approximately three hours earlier it had been at Freiston Shore, on the Lincolnshire section of The Wash!
R8-GW Red eight (on white) – green white has been seen several times on the Blackwater. He winters on the Exe estuary in Devon but visits Kent during spring and autumn passage, which seems a long way round to get to and from Iceland but works for him.
Dudley and Carol Hird in Kent
The southeast corner of England is an interesting area in which to observe the comings and goings of Black-tailed Godwits. The proximity to French estuaries and position on flightlines between Iceland and Spain/Portugal add extra possibilities for godwit watchers. Many people have provided sightings from this area but Dudley and Carol Hird are the godwiteers par excellence.
On June 29th 2006 we sighted OR-W//W at Oare Marshes and reasoned that this must have been ringed for some scientific purpose and that we should check it out and report it. Thank goodness for the Internet in helping us to find the source and setting us on the path to over 5,000 colour ring combination sightings of a range of species, up to the end of 2015. As time went on we realised it was useful, even important, to understand the different schemes in use by ringers if we were to play our part in the study of migration.
We are lucky, here in Kent, in having a beautiful estuarine system at Oare and Conyer on the Swale, Funton and the whole Motney Hill area on the Medway and the large Allhallows area on the Thames, which can all contain large numbers of waders throughout the year. Our main concern is with the Black-tailed Godwits, as Kent must be of major importance to them on passage and over-wintering. Oare is primarily a roost site (much harder to check for rings) while all our other sites are used for feeding (both legs in full view).
With the help of Pete Potts, godwits have been caught and colour-ringed by Swale Ringing Group in Kent; at Kingsnorth Power Station on the Medway estuary and on the Swale estuary at Harty. As a consequence of this, nearly 40% of our sightings are of Kent colour-ringed godwits. It is quite exciting in that they ring one day at Harty and we see them the next day at Oare.
Our total number of individual Black-tailed godwit sighting records cover 479 individual birds, which must mean our estuaries service a lot of godwits in total. In addition to the Kent-ringed birds, 23% have been ringed in Iceland, 10% in France and 10% on the Solent. We also have sightings of godwits from Norfolk, Lincolnshire, Suffolk, Devon, Scotland, Northern Ireland, Portugal, Spain and the Netherlands.
One very interesting godwit was Y8-WG sighted at Oare on July 16th 2012. This adult male was in active primary moult when ringed in Iceland on July 10th, just six days previously. He had flown nearly 2,000 km with only seven out of ten main primary flight feathers – an extraordinary feat of migration. He obviously came to no harm as we have seen this bird back in 2013, 2014 and 2015. We have never seen this bird on Spring passage and, to our knowledge, do not know where it winters or the route it takes back to Iceland. There’s still plenty to find out.
As I write this, in January, we are approaching one of our busiest times, with godwits arriving from the south and staying for nearly three months, as they build up to almost full breeding plumage before departing towards the end of April to their breeding grounds in Iceland. It will be exciting to see which birds have returned to Kent again.
John Parslow on the Ouse Washes
The flooded grassland of the Ouse Washes attract thousands of Black-tailed Godwits, especially in the late winter and early spring.
There will be a separate blog about this critical area in due course but we would like to pay tribute to John Parslow (one of the authors of the Heinzel, Fitter & Parslow field-guide, published in 1972), who was the area’s most prolific colour-ring reader for over a decade. John passed away in November 2015, having spent many a winter day scanning flocks of Black-tailed Godwits, particularly at Fen Drayton, which is not an easy site to work. He has left behind over 1600 records of nearly 300 individual godwits, which is a significant part of the database for the Ouse Washes. His data live on.
Sharing the science
Here’s a list of papers to which colour-ring readers have contributed – so far. Each one comes with a link to the paper:
- Gill, J.A., Norris, K., Potts, P.M., Gunnarsson, T.G., Atkinson, P.W. & Sutherland, W.J. (2001) The buffer effect and large-scale population regulation in migratory birds. Nature, 412, 436-438. DOI: 10.1038/35086568
- Gunnarsson, T.G., Gill, J.A., Sigurbjörnsson, Þ. & Sutherland W.J. (2004) Arrival synchrony in migratory birds. Nature, 431, 646-646. DOI: 10.1038/431646a
- Gunnarsson, T.G., Gill, J.A., Potts, P.M., Atkinson, P.W., Croger, R.E., Gélinaud, G., Gardarsson, A. & Sutherland, W.J. (2005) Estimating population size in Icelandic Black-tailed Godwits Limosa limosa islandica by colour-marking. Bird Study, 52, 153-158. DOI: 10.1080/00063650509461385
- Gunnarsson, T.G., Gill, J.A., Petersen, A., Appleton, G.F. & Sutherland, W.J. (2005) A double buffer effect in a migratory population. Journal of Animal Ecology, 74, 965-971. DOI: 10.1111/j.1365-2656.2005.00994.x
- Gunnarsson, G., Gill, J.A, Newton, J., Potts, P.M. & Sutherland, W.J. (2005) Seasonal matching of habitat quality and fitness in migratory birds. Proceedings of the Royal Society of London B, 272, 2319-2323. DOI: 10.1098/rspb.2005.3214
- Gunnarsson, G., Gill, J.A., Appleton G.F., Gíslason H., Gardarsson, A., Watkinson, A.R. & Sutherland, W.J. (2006) Large-scale habitat associations of birds in lowland Iceland: implications for conservation. Biological Conservation, 128, 265-275. DOI 10.1016/j.biocon.2005.09.034
- Gunnarsson, T.G., Gill, J.A., Atkinson, P.W., Gélinaud, G., Potts, P.M., Croger, R.E., Gudmundsson, G.A., Appleton, G.F. & Sutherland, W.J. (2006) Population-scale drivers of individual arrival times in migratory birds. Journal of Animal Ecology, 75, 1119-1127. DOI: 10.1111/j.1365-2656.2006.01131.x
- Gunnarsson, T.G., Gill, J.A., Goodacre, S.L., Gélinaud, G., Atkinson, P.W., Hewitt, G.M., Potts, P.M. & Sutherland, W.J. (2006) Sexing black-tailed godwits: a comparison of behavioural, molecular, biometric and field-based techniques. Bird Study, 53, 193-198. DOI: 10.1080/00063650609461433
- Gill, J.A., Langston, R.H.W., Alves, J.A., Atkinson, P.W., Bocher, P., Vieira, N.C., Crockford, N.J., Gélinaud, G., Groen, N., Gunnarsson, T.G., Hayhow, B., Hooijmeijer, J., Kentie, R., Kleijn, D., Lourenço, P.M., Masero, J.A., Meunier, F., Potts, P.M., Roodbergen, M., Schekkerman, H., Schröder, J., Wymenga, E. & Piersma, T. (2008) Contrasting trends in two Black-tailed Godwit populations: a review of causes and recommendations. Wader Study Group Bulletin, 114, 43-50.
- Alves, J.A., Lourenço, P.M., Piersma, T., Sutherland, W.J. & Gill, J.A. (2010) Population overlap and habitat segregation in wintering Black-tailed Godwits. Bird Study, 57, 381-391. DOI: 10.1080/00063651003678475
- Gunnarsson, T.G., Sutherland, W.J., Alves, J.A., Appleton, G.F., Potts, P.M., & Gill, J.A. (2012) Rapid changes in the distribution of phenotypes in an expanding population of a migratory bird. Proceedings of the Royal Society of London B, 279, 411-416. DOI: 10.1098/rspb.2011.0939
- Alves, J.A., Gunnarsson, T.G., Potts, P.M., Gélinaud, G., Sutherland, W.J. & Gill, J.A. (2012) Overtaking on migration: does longer distance migration always incur a penalty? Oikos, 121, 464-470. DOI: 10.1111/j.1600-0706.2011.19678.x
- Alves, J.A., Sutherland, W.J. & Gill, J.A. (2012) Will improving wastewater treatment impact shorebirds? Effects of sewage discharges on estuarine invertebrates and birds. Animal Conservation, 15, 44-52. DOI: 10.1111/j.1469-1795.2011.00485.x
- Alves, J.A., Gunnarsson, T.G., Hayhow, D.B., Potts, P.M., Sutherland, W.J. & Gill, J.A. (2013) Costs, benefits and fitness consequences of different migratory strategies. Ecology, 94, 11-17. DOI: 10.1890/12-0737.1
- Alves, J.A., Gunnarsson, T.G., Potts, P.M., Sutherland, W.J. & Gill, J.A. (2013) Sex differences in distribution and resource use in a sexually-dimorphic migratory shorebird. Ecology and Evolution, 3, 1079-1090. DOI: 10.1002/ece3.503
- Gill, J.A., Alves, J.A., Sutherland, W.J., Appleton, G.F., Potts, P.M. & Gunnarsson, T.G. (2014) Why is timing of bird migration advancing when individuals are not? Proceedings of the Royal Society of London B, 281, 20132161. DOI: 10.1098/rspb.2013.2161
- Gill, J.A. (2015) Encountering extreme weather during migration: individual strategies and their consequences. Journal of Animal Ecology, 84, 1141-1143. DOI: 10.1111/1365-2656.12412
- Gunnarsson, T.G., Arnalds, O., Appleton, G.F., Méndez, V. & Gill, J.A. (2015) Ecosystem recharge by volcanic dust drives large-scale variation in bird abundance. Ecology & Evolution, 5, 2386-2396. DOI: 10.1002/ece3.1523
Please send reports of colour-ringed Black-tailed Godwits to Jenny Gill (email@example.com). She will reply with full details of any birds ringed on the Wash or forward your e-mail to colleagues running other schemes.
WaderTales blogs are written by Graham Appleton, to celebrate waders and wader research. Many of the articles are based on previously published papers, with the aim of making wader science available to a broader audience.