The Eurasian bittern was extinct as a British breeding bird by the early 20th century but has been brought back from near-oblivion through targeted reedbed creation, representing one of British conservation greatest success stories.
Bittern welfare depends on extensive, well-managed reedbeds with shallow water margins supporting abundant fish and amphibians. Fragmentation of reedbeds into small isolated patches leaves individual bitterns unable to find sufficient food. Severe winters can eliminate the fish prey on which bitterns depend when shallow water freezes. Disturbance at booming sites during the spring breeding season can cause permanent abandonment of previously occupied territories.