Black Tern Welfare: A Rare Passage Migrant

Black terns are rare and declining passage migrants to the UK whose welfare during stopover depends on suitable wetland habitats with abundant aquatic invertebrates.

Key Facts

• Black terns breed in freshwater marshes across Europe and winter in West Africa
• They are rare and declining passage migrants to UK wetlands, primarily in May and August
• Black terns feed by dipping to the water surface to pick invertebrates and small fish
• Wetland loss through drainage has reduced suitable stopover habitats across their migration route
• Their welfare during migration depends on finding adequate food at stopover wetlands to refuel

Welfare Considerations

Black tern welfare during UK passage depends on the availability of suitable freshwater wetlands where they can refuel before continuing migration. These aerial hunters require calm, shallow, invertebrate-rich water surfaces where they can dip and pick prey items efficiently. The loss of traditional passage sites through wetland drainage reduces stopover options, forcing birds to travel further between fueling stops at greater energetic cost. Individuals failing to find adequate food at stopover sites face the welfare cost of departing on migration with insufficient fuel reserves. Conservation of large, productive freshwater marshes that retain their ecological integrity benefits black tern welfare directly during both spring and autumn passage.

What You Can Do

• Support wetland conservation organizations maintaining high-quality freshwater marshes for passage terns
• Record black tern sightings at passage wetlands through BTO surveys to monitor passage trends
• Advocate for wetland protection policies that maintain the ecological quality of migratory stopover sites
• Support Ramsar wetland designation for key black tern passage sites
• Reduce personal and agricultural contributions to wetland eutrophication that degrades stopover habitat quality