In 2026, the Sandwich Tern colony at Pagham Harbour, West Sussex, England, rebounded to a record 756 breeding pairs, producing 570 fledglings, four years after a severe bird flu outbreak wiped out the entire site. This recovery represents a significant success for conservation efforts aimed at restoring seabird populations.

This resurgence offers a hopeful example of how targeted local conservation can help wildlife recover from major disease outbreaks. The success at Pagham Harbour provides a model for mitigating the impact of widespread avian flu, which has caused declines in seabird populations globally.

What the records show

Monitoring reports from 2026 confirm that 756 Sandwich Tern pairs nested at RSPB Pagham Harbour, making it one of England's largest colonies. These pairs produced 570 fledglings. The 2022 Highly Pathogenic Avian Influenza (HPAI) outbreak caused the entire Sandwich Tern colony to be abandoned, leaving zero breeding pairs. Other species also saw increases. Black-headed Gull fledglings surged tenfold from 51 in 2025 to 504 in 2026. Little Tern fledglings rose from 21 to 34. Eighteen pairs of Avocets nested on newly created islands within a saline lagoon at Ferry Pool.

The timeline

In 2022, a severe HPAI outbreak completely wiped out the Sandwich Tern colony at Pagham Harbour, leading to the abandonment of the entire breeding site. Black-headed Gulls and Mediterranean Gulls were also affected. By 2026, Sandwich Terns returned in record numbers. This followed several years of conservation efforts by Royal Society for the Protection of Birds (RSPB) staff and volunteers.

What changed and for whom

The Sandwich Tern colony's return, from non-existent in 2022 to 756 breeding pairs in 2026, marks the most significant change. This established one of England's largest Sandwich Tern colonies. The RSPB implemented a conservation strategy involving hundreds of hours of work from staff and volunteers. Key actions included managing and restoring existing islands, and creating new ones, such as an island formed in 2021 at Pagham Harbour. These habitats provided suitable nesting spaces for ground-nesting birds along the Solent. The reserve team annually manages vegetation, installs exclusion fencing to deter predators, and enforces biosecurity against rats. Continuous monitoring via cameras and direct observation, with patrols by rangers, minimized disturbance. Wetland enhancement, specifically new islands in Ferry Pool, provided safer nesting areas for species like avocets. These efforts form part of the broader Solent Seascape Project, supported by local authorities including West Sussex County Council, Chichester District Council, and Arun District Council.

What the subject has said publicly

Wez Smith, RSPB Senior Project Manager, acknowledged the severe impact of HPAI in 2022, which caused the abandonment of the Pagham Harbour colony for Sandwich Terns, Black-headed Gulls, and Mediterranean Gulls. He stated, "It's taken several years of dedicated conservation action, but the situation began to 'tern' around last year, and the site is now thriving with record-breaking populations using it".

What we could not confirm

We could not confirm the specific number of Mediterranean Gulls affected or how their population has recovered. We also could not confirm the exact number of staff versus volunteer hours contributed to the conservation efforts.