Britain’s Loudest Bird Booms Back: Record Number of Bitterns Recorded

The bittern is a master of disguise. A stocky, streaky-brown member of the heron family, it spends its life hidden among dense reedbeds, so secretive that birdwatchers often go years without glimpsing one. But what the bittern lacks in visibility it more than makes up for in voice: the male’s deep, resonant “boom” during the breeding season is the loudest call of any bird in the UK, carrying for miles across the wetlands. In March 2025, conservationists had cause to celebrate as that booming chorus reached a new high.

A record 283 booming male bitterns were recorded across the UK in the latest survey by the RSPB and Natural England, a twenty percent increase over the previous count and the biggest single jump since systematic monitoring began in 1990. More than half the population was found on RSPB reserves, with key sites including Minsmere, Lakenheath Fen, and Ham Wall, while booming was also heard at a number of new locations — a sign the birds are spreading into freshly restored habitat.

“A stocky, streaky-brown member of the heron family, it spends its life hidden among dense reedbeds, so secretive that birdwatchers often go years without glimpsing one.”

The recovery is all the more remarkable given how close the bittern came to vanishing. The species was driven extinct in Britain by the late nineteenth century through habitat loss and persecution, returned to Norfolk around 1900, then crashed again to just eleven booming males by 1997. A targeted, large-scale conservation effort, led by the RSPB and Natural England, identified the importance of large, healthy reedbeds with plentiful fish and set about creating and restoring exactly that kind of wetland across the country.

As RSPB senior conservation scientist Simon Wotton put it, wetlands are incredible places for nature, and the bittern’s breeding success is a shining example of effective conservation. The booming bittern story shows how restoring habitat — reedbeds in this case — can bring a species back from the very edge. With careful management, these atmospheric wetlands now echo each spring with the deep call of a bird that very nearly fell silent forever.