Iceland 2026: building new research into 38 years of Whooper Swan monitoring
By Kane Brides, Iceland Whooper Swan Study Group
August 2026 saw members of the Iceland Whooper Swan Study Group come together in Iceland for another season of fieldwork on the Icelandic Whooper Swan Cygnus cygnus population.
This year marked the 38th year of the long-running Icelandic–Anglo–Irish collaboration studying this population. Scientists and fieldworkers from Iceland, the UK, Ireland and China came together for the 2026 expedition, continuing a programme that has developed from long-term colour-marking and resighting into an increasingly integrated study of movement, demography, breeding ecology and behaviour.
Maintaining that long-term monitoring remains a fundamental objective of our annual fieldwork. However, one of the strengths of a study spanning almost four decades is the opportunity to build new research questions and technologies around an established population of individually known birds. This year, several strands of work came together particularly well.
From GPS movements to breeding outcomes
Earlier in the breeding season, remote cameras were deployed at a number of Whooper Swan nests in Iceland. The cameras recorded throughout incubation, providing information on nest outcome, the timing of failures and, where visible, their possible causes.
Several of the nesting females were also carrying GPS transmitters. Retrieving the cameras during the August expedition therefore gave us an opportunity to bring together two complementary datasets: direct observations of what happened at the nest and the movement behaviour recorded remotely by GPS.
Our aim is to determine whether successful and unsuccessful nesting attempts produce sufficiently distinctive movement signatures to allow breeding attempts and their outcomes to be inferred from tracking data alone. Similar approaches have been explored in other bird species, but we are interested in identifying what these behavioural signatures look like specifically in Whooper Swans.
If successful, this could provide a useful means of extracting considerably more demographic information from tracking programmes. Rather than GPS devices telling us only where birds move, they may also allow us to identify when females attempt to breed, estimate incubation periods and potentially determine the timing and outcome of nesting attempts in birds occupying remote areas that would otherwise be difficult to monitor.
The nest-camera material also provides opportunities beyond validating the GPS data. Working with animal behaviour researcher Paul Rose and students, we hope to use the thousands of images collected to investigate the at-nest behaviour of incubating females and how this changes through the incubation period.
A female Whooper Swan incubating eggs during a snowy period in late May 2026.
“For much of their lives, Whooper Swans are out of sight. GPS tags and remote cameras are allowing us to follow the story when we’re not there to watch it.”
Tracking the Whooper Swan family
Another development in 2026 took us in a rather different direction: from individual movements to the movements of entire families.
Colour-ringing has been central to studies of Whooper Swan social and family relationships for many years. Resightings can reveal when parents and offspring remain associated, but inevitably provide snapshots of those relationships rather than a continuous record.
This summer, for the first time within the study, we GPS-tagged whole family groups, fitting transmitters to both parents and their cygnets. By mid-August the cygnets were sufficiently developed for transmitters to be safely deployed, which was one reason our fieldwork took place somewhat later than in previous years.
Following all members of the same family simultaneously should allow us to investigate the process of family dissolution at a resolution that has previously been difficult to achieve. When do individual cygnets begin moving independently of their parents? Does separation occur gradually or abruptly? Do siblings remain together after leaving their parents? And how consistent are these patterns among different families?
We are particularly interested in the possibility of extended parental care. Whooper Swan family associations are well known to persist through the first winter, but simultaneous tracking creates an opportunity to examine whether parent–offspring associations persist beyond this period and, potentially, into subsequent years.
The real value of this work will therefore emerge over the coming months and years as the movements of different family members begin to diverge – or perhaps, in some cases, continue to overlap.
A brood of Whooper Swan cygnets.
Building capacity across the flyway
Long-term studies depend as much upon transferring skills between people as they do upon maintaining datasets.
This year’s expedition was joined by University of Galway PhD student Sammy Pooley. Sammy’s research examines how Whooper Swans and Greenland White-fronted Geese use Ireland’s turloughs – seasonal wetlands whose hydrology changes considerably through the year. Capture and GPS-tagging of both species will form an important component of his research.
Iceland therefore provided an opportunity for intensive practical training alongside an experienced capture team. During the expedition Sammy gained experience in swan capture, safe handling, ringing, biometric measurements and the fitting and deployment of GPS transmitters. These skills can now be applied directly to his research in Ireland.
For an international research network such as the Swan Specialist Group, this aspect of collaborative fieldwork is particularly important. Techniques and experience developed through one long-term study can be transferred between projects and countries, while early-career researchers gain access to expertise that can be difficult to acquire through formal training alone.
PhD student Sammy Pooley with a boat load of Whooper Swans for colour-marking.
Maintaining a 38-year study
Among all these newer research questions, there remains a much simpler objective each summer: catch and mark more swans.
Individually marked Whooper Swans have provided the foundation of the Icelandic study for nearly four decades. Resightings across Iceland, Britain, Ireland and increasingly elsewhere in Europe have allowed individual life histories to accumulate, providing information on movements, migration, survival, breeding and population dynamics.
But maintaining a marked population requires continual effort. Birds die, disappear or become unavailable for observation, and without regular recruitment of newly marked individuals the effective sample size of any long-term study inevitably declines.
Colour-marking another cohort in 2026 was therefore every bit as important as deploying the latest tracking technology. The birds marked this summer become the newest individuals in a dataset extending back 38 years and some may continue contributing observations for many years to come.
There is also an important complementarity between these approaches. GPS tracking provides exceptionally detailed information for a relatively small number of individuals, while colour-marking allows much larger numbers of birds to be followed over long periods. Used together, they allow us to ask questions at spatial and temporal scales that would be difficult to address using either approach alone.
International collaboration at the heart of the study
The 2026 expedition once again demonstrated how international the study of the Icelandic Whooper Swan population has become. Fieldwork brought together researchers and fieldworkers from Iceland, the UK, the University of Galway in Ireland and the Chinese Academy of Sciences, alongside the much wider network of observers whose resightings sustain the study throughout the flyway.
We are particularly grateful to Prof. Cao Lei and SinoBON-Bird for the continued technical and equipment support. Since 2024, SinoBON-Bird has supported the deployment of more than 100 tracking devices within our long-term research on Icelandic Whooper Swans.
We are also grateful to the Náttúrufræðistofnun – Natural Science Institute of Iceland for its continued support with permissions, licensing and metal rings, and to the many Icelandic landowners who continue to provide access and make the fieldwork possible.
Finally, thanks go to everyone involved in the 2026 expedition and to the much wider network of volunteer ring readers who report marked Whooper Swans throughout Iceland, Britain, Ireland and continental Europe. Long-term studies are ultimately built from thousands of individual contributions, often accumulated over decades.
The Iceland Whooper Swan Study Group is currently led by Kane Brides, Sverrir Thorstensen and Dr Ólafur Einarsson, working alongside a wider team including Ketill Thorstensen, Dr Stephen Vickers, Dr Kevin Wood, Sammy Pooley, Prof Cao Lei and Dr Eileen Rees, together with the extensive network of observers who contribute resightings.
Thirty-eight years after the study began, there is still plenty left to learn. What has changed is the toolkit available to us: from individually identifiable rings and notebooks to GPS telemetry, accelerometers and remote cameras. Combining those newer technologies with a long-term study of known individuals is opening up questions that would have been difficult to imagine when the first birds were marked in the late 1980s.
And, importantly, the colour rings going onto birds today ensure there will still be Whooper Swan life histories to follow and new questions to ask in the years ahead.
