During these journeys, migratory birds face countless obstacles: adverse weather conditions, scarcity of resources, predation, habitat loss and, increasingly, changes resulting from human activity. This remarkable display of endurance, orientation and adaptation not only inspires admiration, but also represents an essential component of ecosystem functioning on a global scale. It reveals the profound ecological interconnectedness of the planet, linking continents and ecosystems in a dynamic balance on which countless forms of life depend.

The study of migration is essential for understanding the biology of species and assessing the health of our environment. Migratory birds are valuable indicators of environmental change, as variations in their routes, timing or distribution areas make it possible to detect ecological transformations of great significance for biodiversity conservation. Their continued monitoring provides key information for conserving biodiversity and anticipating the effects of global change.

Interest in uncovering the secrets of bird migration dates back to Antiquity. Aristotle already reflected on the fate of birds in winter, although his interpretations, such as the supposed hibernation of certain species, were far removed from what we know today. Over the centuries, knowledge advanced through systematic observation and, decisively, with the development of scientific ringing at the end of the 19th century. For the first time, this made it possible to track the movements of individual birds and laid the foundations for the modern study of migration. Since then, millions of birds have been marked, generating essential information for reconstructing migratory routes and defining breeding and wintering areas.

The introduction of new technologies has represented a major qualitative leap in this field. Tools such as radio telemetry and automated tracking networks have greatly increased the capacity to obtain data and knowledge about migration. More recently, tracking technologies using geolocation and GPS devices have revolutionised the field, providing data with unprecedented precision, recording frequent and accurate locations and revealing complete routes, stopover areas and flight behaviour. They also make it possible to study migration in “real time” and understand how environmental factors such as climate, land use or habitat degradation influence the movements of each individual, opening up new perspectives for the study of bird migration ecology.

This publication brings together and synthesises the most up-to-date knowledge on the migration of 300 bird species that occupy Spanish territory during some stage of their life cycle, providing a detailed overview of their movements, movement patterns and key areas. This work is also complemented by a dynamic web format that allows texts, tables, charts and maps to be continuously updated, permanently incorporating advances resulting from the application of new technologies and the growing volume of data obtained through scientific ringing programmes. This further expands our knowledge of the different movements that characterise the life cycle of each species, including the complex migratory journeys resulting from thousands of years of evolution.

This atlas aims to become a reference for both the scientific community and those responsible for land management and planning. It also provides land managers with key information for integrating nature conservation into spatial planning, ensuring that land-use planning decisions are based on scientific criteria that support the long-term conservation of biodiversity.

Finally, this work is also a recognition of the collective effort that has made it possible. Over the decades, countless professionals, researchers and ornithologists have contributed, with dedication and rigour, to our knowledge of birds and their movements. Without their constant and often unseen contribution, it would not have been possible to gather the volume of information now being made available to society. Ultimately, this atlas is the result of that shared effort and a testament to the value of collaboration in understanding and protecting our natural heritage.

To all of them, we extend our recognition and gratitude.

Kiko Álvarez
Head of the Species and Sites Unit at SEO/BirdLife

Migratory birds represent, like few other natural phenomena, the global dimension of conservation. Their annual movements connect continents, seas, wetlands, mountains and territories separated by thousands of kilometres, reminding us that ecological processes do not recognise administrative borders and that protecting biodiversity requires a broad, cooperative approach based on the best available scientific evidence.

In this context, the publication of the first Atlas of Bird Migration in Spain represents a milestone of extraordinary importance for the knowledge and management of our natural heritage. This work offers an unprecedented overview of the routes, strategies and migratory patterns of hundreds of species present in our territory, integrating the latest scientific and technological advances and providing a solid basis for better understanding the challenges facing biodiversity in a context of global change.

Its value goes far beyond the strictly scientific sphere. The knowledge brought together in this atlas provides fundamental tools for spatial planning and management, the conservation of natural areas, environmental assessment and public decision-making based on the best available information. Ultimately, it helps strengthen the capacity of our institutions to reconcile nature conservation with economic development and social well-being.

This publication is also the result of an exemplary collective effort. Behind every map, every piece of data and every analysis lie decades of research, scientific monitoring and collaboration among specialists, scientists, ringers, public administrations and organisations committed to the study and conservation of birds. Their work demonstrates the value of shared knowledge and the importance of investing in science in order to address the environmental challenges of the present and the future with confidence.

Spain occupies a privileged geographical position along the main migratory routes of the Western Palearctic. This unique situation gives us a special responsibility for the conservation of migratory birds and the habitats on which they depend throughout their entire life cycle. Works such as this atlas strengthen our ability to fulfil that responsibility with rigour, strategic vision and commitment to future generations.

I trust that this work will become an indispensable reference for researchers, managers, public officials and everyone committed to conserving our natural heritage. Its publication represents a valuable contribution to the development of evidence-based policies and to advancing the objectives that Spain and the European Union have undertaken to protect and restore nature, strengthen ecosystem resilience and halt biodiversity loss.

At a decisive moment for environmental action, this atlas provides essential information for continuing to promote more sustainable spatial planning, strengthening the conservation of our natural areas and species, and advancing the objectives of the State Strategic Plan for Natural Heritage and Biodiversity to 2030, as well as the international commitments undertaken by Spain in the field of biodiversity. Protecting bird migration routes also means preserving the ecological processes that sustain the health of our ecosystems and the well-being of our society.

Science enables us to understand the changes affecting nature; tools such as this atlas also help us make the decisions needed to ensure that future generations continue to inherit a rich, functional and diverse natural heritage.

Hugo Morán Fernández
Secretary of State for the Environment
Ministry for the Ecological Transition and the Demographic Challenge