Little ringed plover with light-loggers

As a pilot study this year 9 Little Ringed Plovers (Charadrius dubius) have been outfitted with 1 g light-loggers (geolocators). These are part of this years CAnMove light logger effort to track migrating birds with this relatively new technique. The workings of light-loggers have been explained by Raymond Klaassen (see blog archive of this site), but in short the device measures the light intensity and store a value with some time resolution (10 min), and from this we get day length and hence geographic position along a time-axis.

The picture on the left shows a male LRP with a just mounted light-logger, seen as a little green blob on the lower back. Project assistant Astrid Hedenström marvels over the avian wing morphology, before releasing the bird . The close-up picture on the right shows the female before relase. Note the brownish ear-coverts and breast band, and a thin yellow orbital ring around the eye, typical female characters in this species. We have great hopes for this species should we manage to re-catch some individuals next year. The Swedish bird ringing atlas suggests a SE migration direction for Scandinavian LRPs, with one amazing recovery from as far as India!

Very welcome to a new CAnMove Postdoc on genetics of migration in willow warblers

Migratory birds are superb navigators. How do they find their way? My research is driven by my major interest in avian biology, particularly the phenomenon of bird migration, aiming to link phenotypic traits to their underlying molecular mechanisms.

How can migratory birds perceive directional information from the Earth's magnetic field and how do they process and integrate this information to use it for compass orientation during their migratory journeys? These were the main questions I focussed on during my PhD, combining experiments on the behavioural, molecular as well as cognitive level. As a Marie-Curie fellow, I extended this general integrative approach into a field situation, though in a different biological context, focussing on the evolutionary genetics of the timing of reproduction in wild bird populations. Here I moved from characterising the genetic variation of candidate genes through determining whether there are any associations with the phenotypes of the birds and the environments where these individuals live, to measuring the selective consequences of that genetic variation.

I am very much looking forward to working on the "Genetics of migration in willow warblers" at the CAnMove center in Lund, a project that transfers the framework and methodology I learned during my postdoctoral period into the field of bird migration that I worked on during my PhD time to which the evolutionary genetics and genomics approaches of the modern era just start getting applied to. /Miriam

Very welcome also to Miriam Liedvogel who will work as a postdoc on genetics of migration in willow warblers together with Staffan Bensch and Susanne Åkesson. We are all much looking forward to the arrival of all Postdocs this autumn and wish you all very welcome to Lund!

Have a nice summer!
Susanne

Welcome to a new CAnMove Postdoc on partial migration in fish

"I am broadly interested in the question of why individuals of the same species vary in their behaviour and life-history. What ecologicalfactors drive the differences we observe in nature, and why isvariation between individuals maintained? During my Ph.D Iinvestigated the role of early experience in the phenotypicdevelopment of the guppy. I manipulated the early social and physicalenvironment of juveniles and assessed how this affected theirbehaviour and morphology as adults. At Lund University as part of theCAnMove project I will investigate the causes and consequences ofpartial migration in roach, asking why certain individuals make thedecision to migrate and others to stay. To do this I will carry outbehavioural trials in the field, analyse long-term data sets onmigratory patterns and potentially investigate a genetic basis formigratory tendency in this species."Best wishes, Ben

Very welcome to Ben Chapman who will work on partial migration in fish during his postdoc financed by CAnMove! Ben will work with Christer Brönmark and Lars-Anders Hansson and some other PIs during this postdoc in Lund.

/Susanne

New CAnMove postdoc on insect flight: Welcome Sophia Engel!

Together with my co-PI Anders Hedenström, I am pleased to introduce our first CAnMove postdoc Sophia Engel. Sophia will join CAnMove soon on a project dealing with insect flight adaptations and evolutionary ecology, dealing with adaptations for dispersal and predator avoidance. This is an exciting project that will combine field and wind tunnel studies, using moths and calopterygid damselflies as model organisms. Both Anders and I are thus extremely happy to host Sophia as a shared postdoc. Below, I will let Sophia introduce herself in her own words:

"I am interested in the interaction of physiological capabilities, ecology, and evolution in shaping a species’ life-history. My previous research has been at the interface of ecology and physiology: For my doctoral work I focused on avian migration. I combined wind tunnel studies and detailed measurements of water- and energy budgets at various ambient conditions with modeling approaches, and showed that dehydration can be a limiting factor for flight duration under naturalistic ambient conditions for my model species, the Rose-coloured Starling. A more recent project is focused on understanding the effects of climate variability on primary productivity, arthropod consumer performance and ultimately the structure and function of the food web in the Chihuahuan Desert of central New Mexico. I am looking forward to combine these two lines of research, wind tunnel studies and insect ecology, in the project “insect flight and morphological trade-offs” at the CAnMove center in Lund!"

Painted ladies continue to migrate north

As some of you might have noted, and which I highlighted in another recent blog, the Painted ladies (tistelfjäril) are migration into Sweden in high numbers this spring. Lars Pettersson (lars.pettersson@zooekol.lu.se) at the Department Ecology has compiled an animation showing the movement of observations of Painted ladies in Sweden during late May and early June. Lars has also been interviewed for the radio channel Sound of Science in the UK on the matter. Please find the broadcast and the animation at the following link. www.soundofscience.wordpress.com

You may find more and updated information on observations of Painted ladies at:
http://www.artportalen.se/default.asp

Have a Great Summer and I hope you will see many Painted Ladies in the Swedish landscape!

Susanne

Lesser black-backed gulls Karla and Linnea – satellite tracking at Stora Karlsö

2009-06-11 Stora Karlsö

This week I have been away on field work trip to Stora Karlsö located west of the Island of Gotland in the Baltic Sea. I have been here with my collaborators Olof Olsson at Stockholm Resilience Centre and Jonas Sundberg at the Baltic Seabird Group. We have attached satellite transmitters to two female lesser black-backed gulls (Larus fuscus) breeding at the island in order to study the foraging movements and migration. The two females were captured at their breeding sites at the south coast of the island. The satellite data is currently being visualised at seaturtle.org (see link below) and you may find maps generated regularly to see the movements of the gulls.

Stora Karlsö is one of the first protected areas in the world, and is considered the second protected area after Yellowstone National Park. With its calcareous rocks Stora Karlsö has an extremely diverse and rich flora, and with its location at the east coast of Sweden St Karlsö has the highest number of hours with sunshine in a year for Sweden. Apart from having a ca 390 pair large lesser black-backed gull colony, there are also a number of other seabirds breeding at the island, such as Guillemots, Razorbills, Cormorants, Arctic terns etc. It also inhabits one of the largest breeding populations of barred warblers (Sylvia nisoria) in Sweden (ca 15 pairs).

You may find maps of the movements of the two lesser black-backed gulls Karla and Linnea at:
http://www.seaturtle.org/tracking/?project_id=408

Susanne

The Anatomy of a Contact Zone

It’s raining once again here in the mountains of middle Sweden. We are strattling the border with Norway at the secondary contact zone for two subspecies of willow warblers which breed here in the birch forests. Each day we head out with our rain gear, poles, and mist nets to target trap willow warblers using an audio playback of their song. When we first arrive at our field site we get out of the car and listen. Once we have located a singing male, we hike over to his territory and start the playback; most of the time their response is immediate and aggressive. We quickly deploy the net and hopefully within minutes have a bird in the net.

Each year millions of willow warblers (Phyllscopus trochilus) migrate north from Africa to Sweden to breed. There are two subspecies, P. trochilus acredula which winters in east to south Africa and breeds in northern Sweden, while P. trochilus trochilus which winters in west Africa and breeds in southern Sweden. Each takes a different migratory route to Scandinavia where they meet in a secondary contact zone in middle Sweden. This contact zone lies between 61 and 63 degrees latitude. Here we have come for the past two summers in an attempt to better define the contact zone and our understanding of the factors that maintain and limit it to a narrow and apparently stable area.

This year we arrived at the beginning of May driving north from Skåne following the migrating willow warblers north and the leafing out of the birch (Betula pubescens and B. pendula). Birch is a key species indicating the presence of willow warbler habitat. On the first of May just north of Mora the birch made an abrupt transition from leafing out to still having dormant buds. In addition, the song of the willow warbler disappeared from the birch forests. By the time we had reached Ljungdalen, it was still winter transitioning to spring. It was ten days before the first willow warbler showed up on the Flatruet (the highest road in Sweden).

It was another three days the before next willow warbler arrived and then they began to fill into this region. The month of May has been extremely exciting. Tracking the phenology of migration and the subsequent breeding of a single species gave us the opportunity to see the transition of winter to spring and then to summer (we hope) as the snow melts, the trees leaf out and the wildflowers bloom. While the landscape comes to life we witnessed the spectacular migration of all the other birds that breed in the mountains of Sweden. The first hearty migrants to arrive were the thrushes, finches, and gulls. The hay meadows in Ljungdalen were filled with thousands of fieldfares for over a week. The next to arrive were the waders. On cold and snowy days the golden plovers would take refuge in the valley and marshlands around the Storsjön. Gradually the insectivorous birds showed up with the warming weather. The first house martins signaled the abundance of insects was finally sufficient and we began to see willow warblers in larger numbers. By the end of May most of the willow warbler territories were occupied. The last migrant we encountered was the long-tailed jaeger which breeds up on the tundra and in montane habitats above the treeline.

Waiting for the first females to arrive, we went out each day to field sites in both low and high elevation birch habitat to identify all the territories and trap the males. We used playback and mist nets to capture the birds. When the males first arrive on their territories they are less aggressive but still easily captured. Gradually as the territories became denser as they shrink to a stable size tolerated by all the neighbors, the birds became more aggressive and responded very quickly to our playback. Sometimes the males are so aggressive they are jumping into the net before we even have it completely setup!

Next the females arrived, the males continued their aggressive behavior, fluttering their wings, singing, and flying directly towards our speakers until they were caught. Then the females joined in the aggressive behavior. For about one week we saw the females respond to our playback by calling, fluttering their wings, and aggressively flying towards our speaker. When captured most of them were developing their brood patch and appeared to have eggs developing in their oviducts. Now the females have disappeared presumably to attend their clutches and the males have become much more quiet.

Although each bird is captured as they arrive, we have no idea which subspecies they represent. In order to elucidate the precise region of the contact zone, the timing of arrival, and the breeding phenology for each subspecies, we collected biometrics, blood for molecular analysis, and feathers for stable isotope analysis. Previous studies by our PhD supervisors, Susanne Åkesson and Staffan Bensch, have identified differences in stable carbon and nitrogen isotopes between the two subspecies reflecting their wintering grounds. Each subspecies winters and moults in a different region of Africa allowing us to separate the majority of individuals based on the stable isotope ratios within their feathers. In addition, there are two AFLP markers thought to be associated with the migratory divide at the contact zone.

Despite all the rain and cold this year we have had great success trapping willow warblers. The most exciting aspect of the field work is the large number of recaptures of individuals we trapped last year. This gives us a unique opportunity to compare feather stable isotope ratios of these birds from multiple years. Of course the short-eared owl we saw yesterday and the stunning mountains also makes for a very enjoyable field season…

Keith Larson, Nils Müller, and Sieglinde Kundisch

Fox and terns, no good combination

One of the species we tagged with geolocators last season is the Arctic Tern. This year the ‘only thing’ we have to do is to recapture the tagged birds, and then we will reveal the migration routes and wintering strategies of these fabulous birds. The first signs were very promising; several birds with geolocators were seen near the breeding colony. We catch the birds on the nest, thus we had to wait until the clutch was completed. Finally at least two logger-birds started to initiate nests.

Arctic Tern with a geolocator (lightlogger) on his back

Just a few days before we could capture these birds a low pressure passed southern Sweden. Due to a strong eastern wind the water level in the Baltic Sea dropped and a very narrow land bridge appeared between the tern island and the mainland. When we checked the island the day after, we found it completely empty. All over the place we saw tracks of a Fox… The dozen pairs of Avocets, the Little Terns, Common Terns, and the Arctic Terns (including our logger birds) had deserted the island, leaving their clutches stone cold.

Patrik releasing one of the Arctic Terns with a geolocator that is now back on the tern island...

Terns are quite well known for their ability to relay if the breeding is terminated this early in the season. As long as water level does not drop again, and thus our ‘friend’ the fox cannot reach the island, we still have a good chance to recapture some Arctic Terns and to retrieve the data. The latest news is that indeed the terns have started all over again. Two logger-terns are paired with each other and are scraping a nest. No eggs yet, thus the question remains whether we or the fox will be first this time…

Great Snipe bonanza

A so-called ’geolocator’ is a minute electronic device that logs light intensity over time. As the sun rises at different times at different longitudes, and as the length of day varies with latitude, light records can be used to derive the approximate location of the loggers on the globe (± 300 km). The latest geolocator model only weighs 1 gram. This has opened the exiting opportunity to track, for the first time, the migrations of small passerine birds (see Stutchbury et al. 2009). One important limitation of geolocators is that these tags have to be retrieved in order to obtain the data. The technique can thus only be used for birds that are faithful to their breeding site.

Example of a light registration over time from which location estimates can be derived.

While discussing the use of geolocators the Great Snipe was one obvious candidate species. Very little is known about the migration habits and wintering quarters of this endangered Swedish breeding bird. For example, no ring recoveries are known from Africa, the region where Scandinavian birds are supposed to spend the winter. Great Snipes return to their breeding areas, and thus geolocators can indeed be used to reveal their migratory movements and wintering areas. We decided to start a pilot project and to apply geolocators on 10 Great Snipes. We choose to work in Jämtland (near Enafors/Storlien) where people from the Ånnsjön bird observatory know the local Great Snipe population very well.

Great Snipes are best caught at so called ‘leks’, traditional places where males assemble at dusk to display. As females only visit the leks to pair, and are thus more difficult to catch in a subsequent year, we decided to focus on males. People from the bird observatory were especially interested in females as they aim to track them during the breeding season to find out where they breed and where they raise their young. So males for geolocators, females for radiotransmitters. Would the three nights that we had planned be enough to capture 10 males?

The first evening we visited a lek (Sträton) a few kilometres from the Storulvan tourist station. With the help of a GPS we located the centre of the snipe lek. Here and not 50 metres to the left or right the Great Snipe show would happen tonight. We encircled the lek with special wader mistnets. This type of net is the most efficient to catch larger birds as the net is less visible and the birds get well entangled. As soon as the sun set the Great Snipes arrived to the lek and started to display. By walking the lek the birds could be flushed into the nets. This turned out to be an extremely efficient way to catch. The first night we already caught 21 birds! In fact we believe that we caught all the males that were present at this lek. Already after 3 hours of catching all 10 geolocators were applied, mission completed. Six out of the 21 birds were females, thus we could also apply six radiotags. The hardest part of the job was probably that we had to walk all the way back with all the equipment as we were exhausted after a night of catching. It must have been the unbeatable singing Bluethroats that kept us on our feet...

Walking uphill with all the catching equipment

View on one of the leks where we caught birds.

Peter Carlsson from the Ånnsjön bird observatory is extracting a snipe from the net.

One of the Great Snipes in the hand. Note the moult contast in the primary coverts.

Great Snipe with a geolocator mounted on the leg ring.

The happy field team procesing birds. Great teamwork!

In the subsequent two nights we visited two other leks. Catching was at least as efficient there. The unofficial world record in catching Great Snipes is now set at 24 birds per night! In total we caught 52 birds during three nights. Eight of these were already ringed in previous years (controls). Twelve birds were females. A great success for a relatively short visit!
Next year is going to be even more exciting as we then we hope to recapture some of the males at their lek. Will the Great Snipe finally reveal its migration habits?

Some relevant links:
Geolocators are produces by BAS: www.birdtracker.co.uk
Stutchbury et al. (2009): www.sciencemag.org/cgi/content/abstract/323/5916/896

Painted lady migration

Dear All,
Perhaps some of you have noted that there has been intense migration north by Painted ladies (tistelfjäril) in Europe this year, and a high number of butterflies have been observed also in Sweden. You may see the observations reported to Artportalen. Please, find below a report (and photo) by Pål-Axel Olsson from his field observations at the east coast of Skåne (Österlen) where he has observed many painted ladies during the spring. Have anyone else made observations of painted ladies this spring? If so, please, make sure to report your observations to http://www.artportalen.se/.
/Susanne

Pål-Axels observations (in Swedish):
En stor mängd tistelfjärilar har sträckt in till Sverige under våren. Arten har varit talrik i Skåne sedan mitten av maj enligt Artportalen. Redan innan dess var den vanlig på många håll i mellersta Europa. Fjärilarna har troligen kläckts i Nordafrika och sedan sträckt norrut. I Sverige har de varit särskilt vanliga i Skåne, på Västkusten, Öland och i Sörmland.
I Skåne har jag sett tistelfjärilar på de flesta lokaler jag besökt på Österlen under våren. Jag har sett dem i Lyngsjö, Everöd, Brösarp, St Olof, Vitaby, Kivik, vid Klammersbäck, Kumlan och på Ravlunda skjutfält. I sandmarkerna har tistelfjärilarna ofta besökt gråfibbla.
Pål Axel Olsson, Ekologiska institutione

Paper on long-distance dispersal and fragmented landscapes

Hi All CAnMovians,

Georg Andersson found this article on long-distance dispersal and the importance of data on animal movements which looks very interesting. Please, check this link: http://www.esajournals.org/doi/abs/10.1890/08-1903.1

This time of year keeps many of us busy with field work - good luck with that and whatever else you might be doing at this time of the year!

Susanne