Black Tern, Chlidonias niger, is a species of seabird found in wetland and river and lake ecosystems.

Chlidonias niger has a breeding population size of 11100-20600 pairs and a breeding range size of 125000 square kilometres in the EU27. The breeding population trend in the EU27 is Decreasing in the short term and Decreasing in the long term.

The EU population status of Chlidonias niger was assessed as Declining, because EU27 population or range declined by at least 20% since 1980, with continuing decline since 2001.