The bittern – a type of heron extinct in the UK at the turn of the 20th Century – is bouncing back to full recovery, according to the RSPB.

Scientists count bitterns by listening for the male’s foghorn-like booming song, and, this year, more than 150 males have been recorded in England and Wales, with numbers not thought to be surpassed since early in the 19th century.

Last year, there were 140 booming males across 61 sites recorded.

Bitterns have been recorded at both Roswell Pits, in Ely, at Wicken Fen, and at Lakenheath Fen.

Bittern numbers peaked at around 80 booming males in the 1950s, but had declined to only 11 males in England in 1997.

Concern over a second UK extinction led to a concerted conservation program which is driving the current recovery. The bittern was absent as a breeding bird between the 1870s and 1911.

During the breeding season, the bittern prefers sizeable tracts of wet reedbed – a habitat which, two decades ago, in the UK had become scarce and under managed.

Simon Wotton, a RSPB conservation scientist, said: “In the late 1990s, the bittern was heading towards a second extinction in the UK, largely because its preferred habitat – wet reedbed – was drying out and required intensive management, restoration and habitat recreation.

“But thanks to efforts to improve the habitat, combined with significant funding from two projects under the European Union Life Program, the bittern was saved, and we’re delighted that its success keeps going from strength to strength.”