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Birds contend with a range of human impacts, including habitat change, overexploitation, invasive alien species, pollution and environmental contaminants, and climate change, which together comprise the five major drivers of biodiversity decline recognized by the UN’s Convention on Biodiversity. However, within and in addition to these five major threats, several challenges to bird conservation are often overlooked, but demand investigation and interventions.

“Green” energy projects using new technologies and materials, for example, may create ecological traps that cause bird mortality or drive habitat destruction that lowers reproductive success. Well-known examples include wind farms killing large numbers of raptors. Still, less familiar instances include solar panels creating “lake effect” illusions that can result in waterbird mortality, and hydroelectric power projects altering riparian habitat in ways that undermine birds’ reproductive success, for example, the Black Stork (Ciconia nigra) in Europe.

Reintroductions of formerly endangered species may also have unintended negative impacts, such as in the case of bird declines correlated with Peregrine Falcon (Falco peregrinus) and American bison (Bison bison) reintroductions in North America.

In Africa and Asia, new and expanding markets for birds used in traditional medicine and magic as well as ornaments and in singing competitions are threatening to drive declines and extinctions of hornbills (Bucerotidae), Old World vultures (Accipitridae) and white-eyes (Zosteropidae) among many other avian taxa.

What do we know about these problems and the magnitudes of their impacts on birds, and what do we need to investigate? What can be done or is being done to quantify the extent of such problems and to test effective solutions?

One 15-min oral presentation will be selected from the submitted abstracts.


Nico Arcilla and Māris Strazds

Contaminants are globally distributed, and while the concentrations vary between regions, there is no truly pristine region left. Exposure to contaminants can have a wide array of consequences on wildlife health, behaviour, reproduction, and survival, even contributing to population declines.

Birds create awareness of pollution issues. Monitoring bird populations provides an early warning of processes going on at the population level: ornithologists have pointed out declining bird populations in the past which were later linked to the introduction of contaminants in the environment. Probably the most famous case so far is the ban in most countries of DDT following its dramatic impact on bird populations.

Contaminant levels in birds reflect chemical exposure from their environment and uptake via their diet. Studies may focus on local, acute exposures to long-term contamination, from specific locations to flyways as well as on transgenerational effects. Feathers, blood, faeces, eggs—the matrices used in avian chemical exposure monitoring schemes are varied and they provide opportunities to address a large panel of questions.

The contaminants found and their levels in the different matrices provide insights into sources and pathways on chemical transfer in the environment. Which contaminants have been found in birds and how they might affect the populations are crucial questions which can contribute to a more robust regulation of chemical use.

Hence this symposium aims to be a platform to share knowledge on ongoing studies on contaminants in birds, their effects, and on promising cutting-edge methods to further our understanding of how contaminants might impact birds.

One 15-min oral presentation will be selected from the submitted abstracts.


Céline Arzel, Amalie Ask, Claire Bottini

Shifting precipitation patterns are an underappreciated consequence of climate change. Increasing evidence demonstrates how changes in precipitation can affect all aspects of avian biology, from physiology to population demography.

The focus on temperature as the primary driver of avian responses to global change arises from the clear, directional nature of changes in temperature across the globe. Conversely, the direction and magnitude of changes in precipitation are harder to anticipate and likely to show strong variation between regions and habitats, resulting in divergent impacts on different functional and taxonomic groups.

Therefore, a thorough understanding of the consequences of precipitation for the persistence of individuals, populations, and communities, and the mechanisms underlying these effects, is essential for anticipating and mitigating the impacts of climate change on avian systems.

This symposium seeks to focus attention on recent work quantifying the effects of rain and snowfall across scales and environments, including birds occurring in different climatic zones and habitats. The ultimate goal is to underline the central importance of this “second axis” of climatic change in shaping the current and future state of birds.

Two 15-min oral presentations will be selected from the submitted abstracts.


Joseph Burant, Malcolm Burgess, and Nikole Freeman

Birds host complex microbial communities in different body regions including the digestive tract, uropygial gland, skin and feathers, that play fundamental roles in their immune system, physiology, digestion, and behaviour. Recent years have seen a surge in wild avian microbiome research, with our understanding of the eco-evolutionary dynamics of avian-microbe symbiosis growing rapidly.

Despite this newly acquired knowledge, insight into how the microbial symbionts of birds influence host adaptation and evolution and what functional roles they provide in different contexts, still remain to be explored. Thus, the field is on the precipice of understanding the ultimate factors that shape microbial community structure in relation to the rich evolutionary, ecological, and dietary diversity of birds.

European Ornithologists' Union Congress provides an ideal place for bringing together researchers studying host-microbe interactions in a variety of avian systems. This symposium will highlight and discuss novel findings related to eco-evolutionary dynamics of avian microbiomes, addressing important questions spanning several areas of ornithology.

Two 15-min oral presentations will be selected from the submitted abstracts.


Charli Davies, Elin Videvall, and Kasun Bodawatta

The natural environment is changing at an unprecedented rate, resulting in many ecological challenges for wild populations. Cognition, referring to the processes by which animals collect, retain and use information from their environment, plays a major role in driving behavioural flexibility, a powerful way for individuals to adjust their behavioural repertoire to face these new challenges.

The field of animal cognition has expanded rapidly over the last 10 years, and our understanding of the factors driving the evolution of cognitive abilities has been greatly enhanced by comparative studies encompassing a wide range of taxa. However, exploring the links between variation in cognitive performance and fitness at the level of the individual is only beginning to emerge within non-human species.

How cognition can shape animal responses to environmental changes and potentially mitigate anthropogenic impacts has recently received increasing interest, especially in avian species, which show high levels of flexibility and adjustment to environmental conditions.

In this symposium, we aim to bring together ornithologists working with an individual-based approach to highlight the advances in the field of animal cognition, especially regarding the links between cognition and adjustments to environmental changes.

We dedicate this symposium to the memory and work of our friend and colleague, Julie Morand-Ferron, who had a major impact on our understanding of cognition in the natural environment.


Laure Cauchard, Blandine Doligez, John Quinn, and Eva Serrano Davies

Endocrine systems are critical regulators of several adaptive physiological and behavioural processes, which animals rely on every day throughout their lives. Given such functionality, many facets of the endocrine system show clear signs of divergence among species, including even closely related taxa. Yet, the precise causes and consequences of large-scale variation in the endocrine system remain poorly understood.

Over the past decades, researchers have begun accumulating hormone data from large numbers of species. This has meant that we can begin conducting major interspecific analyses that look for factors that predict macroevolutionary patterning of hormone system variation.

Meanwhile, the concurrent development and conceptual maturation of modern phylogenetic comparative methods (PCMs) have begun to provide rigorous and powerful tools to help buttress these analyses. To this end, the adoption of PCMs to hormone system datasets has demonstrated a tremendous potential to reveal exciting findings not only about how hormone systems evolve the way they do, but also about how this evolution unfolds.

Our symposium, therefore, sets out to share our recent landmark findings in this area of research, while stimulating other researchers to adopt novel ways of thinking about these ideas.

One 15-min oral presentation will be selected from the submitted abstracts.


Bin-Yan Hsu and Matthew Fuxjager

Ornithologists commonly view tropical habitats as stable environments which allow year-round breeding and moult of resident birds, and survival of overwintering higher-latitude migrants. This view is an oversimplification of seasonality in Africa because conditions often fluctuate quite dramatically, for example in terms of precipitation, temperature, and resources.

Birds residing in the Afrotropics, whether year-round or temporarily, must endure these conditions and fit their annual cycle events to them by evolving annual schedules or by flexible adjustments in time and space.

In this symposium, we wish to understand how environmental seasonal fluctuations in Africa affect the scheduling of annual cycle stages in residents and migrant visitors. We will bring together African and European researchers to review our current understanding of seasonality in Africa, and to discuss the effects of seasonal fluctuations on the timing of breeding, movements, and over-wintering behaviour in resident and migrant birds.

Two 15-min oral presentations will be selected from the submitted abstracts.


Crinan Jarrett, Chima Nwaogu, and Barbara Helm

Birds have fascinated animal ecologists and evolutionary biologists for decades as they are incredible athletes, able to prepare their phenotypes for the most enduring worldwide migrations. However, the proximate mechanisms underlying this remarkable life history characteristic are still poorly understood.

Recent research on the physiological mechanisms of migration has focused on certain hormonal axes or oxidative stress physiology, bringing new perspectives to understand species' migratory decisions and performance. However, given the complex relationships between regulatory systems, we currently need more studies, both integrating previous work and exploring new physiological mechanisms, to uncover the selective forces shaping migratory decisions.

This symposium aims to present research on understudied physiological aspects linked with variation in migratory activity, such as telomere length variation, immune function, mitochondrial traits, or microbiome composition, as well as bringing the attention to the use of integrative and/or comparative perspectives.

One 15-min oral presentation will be selected from the submitted abstracts.


Tiia Kärkkäinen and Pablo Salmón

The fast growth in human population and activities over the past century has led to fast changes in the global climate system. Worryingly, these global climatic changes are predicted to be even stronger during the 21st century and become one of the major threats to living organisms.

Nowadays, there are a growing number of well-documented examples in natural bird populations of changes in geographical range, phenology, behaviour, or morphology in response to global climatic changes. There is now an urgent need to understand which traits and why are responding to global climate change, and what the underlying mechanisms are, in order to predict the future of our birdlife.

This symposium aims to showcase how long-term studies coupled with state-of-the-art methodological approaches can shine a light on these ‘burning’ questions.


Giulia Masoero, Maria Moiron, and Pierre Bize

As humans, we easily default to thinking about habitat in two dimensions, dimensions that can easily be described in neat maps on a flat plane. Flying animals however live their lives in three dimensions. Many birds, bats and insects spend a considerable part of their life in the air, making the airspace itself an important, but sometimes overlooked, part of their habitat.

So how should we then think about this part of their habitat? Does the aerial habitat contain structure, analogous to the depth zones of aquatic habitats? Different species, and species groups, almost certainly differ in their vertical space usage, so what factors would we expect to shape this? Is the vertical component of habitats mainly decided by environmental factors such as temperature and wind, or is there also a biotic component where predator/prey interactions or conspecifics affect altitude usage?

This is also likely to be dynamic, and just as space use within a traditional habitat change, there will likely be differences between times of day, seasons, behaviours or even life stages.

Two 15-min oral presentations will be selected from the submitted abstracts.


Cecilia Nilsson and Emily Cohen

Because of their mobility, studying the movement behaviour of birds is particularly challenging, but has recently become increasingly possible with the miniaturization of tracking technologies. How animals move, prospect, and select habitats before, during, and after dispersal, however, is still poorly understood, despite strong influences on population patterns.

Recent studies have shown that prospecting is a dynamic process that allows individuals to gather information about the habitat quality of a potential breeding site and make informed decisions about whether to remain in their current breeding area or to disperse. Prospecting is, therefore, crucial to determine the extent of a species' distribution through colonization processes and population expansion dynamics.

This symposium, therefore, aims to summarize recent advances in monitoring prospecting behaviour. We seek to demonstrate that habitat selection during prospecting is thus part of a developmental continuum and emphasize the importance of tracking different life stages (juvenile, immature, breeding, and non-breeding) to better understand dispersal processes.

Our goal is to bring together researchers from different disciplines and institutions to improve our understanding of different prospection and dispersal strategies. Comparisons of different life stages, marine and terrestrial species during the symposium will help us to better understand the influence of prospecting and habitat selection on distribution and population dynamics.

One 15-min oral presentation will be selected from the submitted abstracts.


Florian Orgeret and Caitlin K. Frankish

Epigenetics is the study of biochemical mechanisms that stably alter gene expression without changing the primary nucleotide sequence of the genome. Such mechanisms include molecular mechanisms like DNA methylation, histone modifications and the involvement of microRNAs.

Studies in a variety of taxa have now shown that these mechanisms are important regulators of phenotypic diversity, both within and between organisms, and provide us with important information on ageing. As such, epigenetic modifications potentially provide a proximate mechanism for environmental cues to shape phenotypic responses. Potentially, these changes might be inherited across generations, which would allow organisms to adapt to environmental change and facilitate rapid evolutionary change.

This has sparked the interest of ecologists, including ornithologists. As there is a large potential for studies on birds to answer many outstanding questions in ecological epigenetics, the number of studies on the causes and consequences of epigenetic variation in birds, also in their natural habitats, is rising.

It is time to reflect on the current state of the avian ecological epigenetics field to determine whether the field has met our predictions, or whether we need to tone down our expectations.

This symposium will provide an ecologically-oriented overview of the current avian epigenetics knowledge and spark discussion to identify critical knowledge gaps and address methodological challenges. We will bring together early-career and senior researchers that encompass research on various avian study systems and the use of different epigenetic methodologies and approaches.

One 15-min oral presentation will be selected from the submitted abstracts.


Bernice Sepers and Rebecca Chen

In our human-dominated epoch, the Anthropocene, the Earth and its ecosystems are undergoing rapid change. Changes in climate and land use can endanger avian diversity and the condition of bird populations through the loss or degradation of natural habitats and essential resources.

Additionally, range expansions, altered migration patterns, and novel ecological interactions can modify long-established relationships between birds and their pathogens and parasites. Ultimately, birds in the role of hosts may differ in terms of tolerance, resistance, and susceptibility across different systems and in different contexts in ways that are influenced by global changes.

These host traits and changes therein are relevant because they, at least partially, relate to a species’ or population’s reservoir potential and an individual’s transmission probability.

In any case, pathogens and parasites affect birds in diverse ways. In terms of organismal biology, pathogens and parasites can affect physiology, modify behaviour, and reduce host reproductive success. However, host-parasite interactions can also drive population dynamics and regulate and structure bird communities or even whole ecosystems.

In our symposium, we bring together different perspectives on the role of birds as the hosts and underline the significance of understanding host-parasite interactions, especially in times of rapid climate change and increased risk of global pandemics.

One 15-min oral presentation will be selected from the submitted abstracts.


Finja Strehmann, Amelia Chyb, and Kevin Matson

Miniature light-level geolocator tags have revolutionized ornithology in the past decade and expanded our knowledge of migration routes and non-breeding ranges even for some of the smallest bird species. Today we know a lot about where birds go and when, but we do not know how they are able to get there.

This is especially true for the vast majority of migratory birds that are too small to carry heavy tracking devices. Currently, the next boom of multisensor tags is around the corner as the miniaturization now also allows for tracking of our most common migrants.

Tags with a fusion of different sensors, such as barometric pressure, acceleration and magnetic properties add important information of activity, flight behaviours and the context of the environment to the position data. This technical advancement promises discoveries of many novel and unexpected behaviours and sheds light on how migratory birds accomplish their complex annual cycles. Astonishing examples are the fine-scale movement inside thermals, flight patterns correlated with the lunar cycle and diel cycles in flight altitudes where birds climb thousands of meters in a short period of time just to cruise at extreme altitudes throughout the day.

Deciphering the reasons for these behaviours is challenging, but observations in the natural context offer the chance for understanding. Ultimately, with multisensor tags, we will gain insight into how birds perform their migration, and how orientation, energetically efficient flight, and social cohesion are achieved.

In this symposium, we highlight promising examples of recent discoveries and propagate the latest methods suited for multisensor data analysis.

One 15-min oral presentation will be selected from the submitted abstracts.


Sissel Sjöberg and Christoph M. Meier

The cold winter months represent significant challenges for birds living at high latitudes in temperate environments due to limited resource availability and harsh environmental conditions. Individuals must struggle to find sufficient resources during the short winter days to acquire enough energy to meet energetic demands associated with thermoregulation and general functioning.

Therefore, winter can act as a strong selection filter and the behaviour of individuals throughout winter can carry over to affect performance in subsequent periods of the annual cycle, including the breeding season.

Although often thought of as a season of cold and icy conditions, climate change means that the weather conditions experienced by birds during the winter months are changing rapidly, with less snowfall and higher temperatures imposing shifting selection pressures on birds. The ability of birds to survive through the cold winter months is crucial for the long‐term persistence of species.

Our symposium provides a platform for ornithologists to present and discuss the historically underrepresented field of the winter ecology of birds. Talks in our symposium will highlight individual strategies to cope with winter and how individual-level effects of winter can scale up to influence populations and communities.

One 15-min oral presentation will be selected from the submitted abstracts.


Alex Sutton and Mark Mainwaring