Conservationists are celebrating a record year for bitterns after a recent survey revealed their numbers have increased by 20% since last year.

Bitterns, once extinct in the UK by the late 1800s due to habitat loss and persecution, made a return to Norfolk in 1900.

The RSPB and Natural England’s 2024 monitoring project recorded 283 “booming” males—the species’ distinct mating call can travel up to three miles.

Simon Wotton, RSPB senior conservation scientist, said: “These bittern breeding success stories are a shining example of effective conservation efforts undertaken by dedicated organisations, landowners and volunteers.”

This marks the largest population increase since monitoring began in 1990.

In 1997, numbers had dropped to just 11 booming males. Since then, conservation efforts—particularly the restoration of inland reedbeds—have helped the species rebound. Research identified that healthy wetlands with abundant fish were key to their recovery.

Now, most of the UK’s bitterns live in reedbeds protected from coastal flooding, offering safer breeding grounds. The RSPB and Natural England credit this success to habitat management and continued monitoring.

Each spring, volunteers and site teams help track bittern populations by listening for the males’ booming calls.

The 2024 survey recorded booming from 12 new sites, and Mr Wotton said: “It is fantastic to see bittern numbers increasing across the country – notably on RSPB nature reserves – thanks to the hard work of staff to create safe havens for this iconic species.

“With the arrival of spring, now is the best time to listen out for their famous boom.”

He added: “As valuable reedbed habitat remains threatened by rising sea levels due to climate change, these vital breeding sites continue to provide important refuge for bitterns and other wetland species.”

Although still rare, bitterns can be heard across several nature reserves in England and Wales, including RSPB Leighton Moss in Lancashire, RSPB Otmoor in Oxfordshire, RSPB Ham Wall in Somerset, and RSPB Valley Wetlands in Anglesey—offering hope for the future of this elusive bird.

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