Black Tern Welfare: Passage Migrants and Freshwater Wetlands

Black terns are beautiful marsh terns that once bred in Britain and now pass through in spring and autumn. Their welfare as passage migrants depends on freshwater wetland quality.

Key Facts

Black terns bred in the UK until the 19th century when drainage eliminated their marsh habitat
They now appear as passage migrants in spring and autumn, mainly at inland reservoirs and lakes
Spring passage birds are in breeding plumage - jet black with grey wings, one of the UK's most elegant visitors
They catch insects in flight over water and pick invertebrates from the surface
Numbers are highly variable and depend partly on breeding success in continental Europe
Loss of shallow, vegetated marsh habitat drove their UK extinction as a breeding species

Welfare Considerations

Black tern welfare as passage migrants centres on finding suitable resting and feeding sites on their journey between wintering areas and continental breeding grounds. Reservoirs and lakes that have shallow vegetated margins provide the surface-feeding habitat they need. In years with poor insect emergence over water bodies, passage birds may struggle to refuel adequately. The historical loss of UK breeding black terns due to marsh drainage is a cautionary tale: restoring shallow marsh habitat could, in theory, attract breeding birds back over time.

What You Can Do

Support creation of shallow marsh and reedbed edges at wetland nature reserves
Report black tern passage sightings to local wildlife trusts and BTO BirdTrack
Donate to inland wetland creation and management projects
Advocate for shallow marsh habitat creation in reservoir management
Support European wetland conservation protecting black tern breeding sites