World's largest Audouin’s Gull colony now established in southern Portugal
Once restricted to the Mediterranean, the species is continuing its remarkable westward shift
A major shift in global population
Ornithomedia reports that the world’s largest colony of Audouin’s Gull is now established in southern Portugal, marking a significant change in the global distribution of this once highly localised species.
Traditionally associated with the Mediterranean - particularly strongholds in Spain’s Ebro Delta - Audouin’s Gull has undergone a striking expansion in recent decades. The emergence of such a large colony on Portugal’s Atlantic coast represents a new chapter in that story.
From rarity to recovery
Audouin’s Gull was once one of Europe’s rarest gulls, with a tiny breeding population largely confined to a handful of Mediterranean sites. Intensive conservation efforts, including protection of breeding colonies and changes in fisheries practices, have helped fuel a steady recovery.
As numbers increased, the species began to spread beyond its traditional range, colonising new sites and gradually extending its footprint westwards. The establishment of a major colony in Portugal suggests this expansion is not only continuing but accelerating.
Why Portugal?
The shift towards the Atlantic coast is likely driven by a combination of factors, including food availability, reduced competition and changing environmental conditions. Ports and coastal areas can provide reliable feeding opportunities, particularly where fishing activity is high.
The southern Portuguese coast appears to offer suitable breeding conditions alongside access to food resources, making it an increasingly attractive location for the species.
Changing patterns in seabird distribution
The relocation of the world’s largest colony is a striking example of how seabird distributions can change over time. While the overall story for Audouin’s Gull is one of recovery, such shifts also highlight the dynamic nature of coastal ecosystems.
They may reflect broader environmental changes, including climate influences, fisheries dynamics and habitat availability - all of which can shape where seabirds choose to breed.
A success story with new questions
The rise of this Portuguese colony is undoubtedly a conservation success, demonstrating how targeted efforts can help reverse declines in threatened species.
At the same time, it raises important questions about the long-term stability of traditional breeding sites and how populations may continue to redistribute in the future.
March 2026
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