Bittern revival: Boom time for UK's loudest bird
Britain's loudest bird, the bittern, has enjoyed its best year on record in England, conservationists have said.
The RSPB and Natural England said the number of breeding males topped 100 for the first time since it returned to the UK in 1911 after becoming extinct here.
The distinctive "booming" call of the male helped researchers track the normally elusive wetland species.
RSPB spokesman Grahame Madge said the increase highlighted by the survey of the birds was "very exciting".
Conservationists say bitterns have a "beatbox" ability to fill their gullets with air which they release to make a booming song that can be heard several kilometres away.
The survey found evidence of at least 104 singing males in England this summer, mainly in East Anglia, an increase from just 11 some 15 years ago.
The bittern has also recolonised the Somerset Levels since 2008 where 25 males were located, up from 14 last year.
Most of the males across England (85%) were found on nature reserves. There were 63 bittern nests recorded at 26 sites.
Mr Madge said: "The fact that these birds have increased so much given the relatively hard winters - and we know they can suffer in the bad weather - is very encouraging."
In the past, the bittern population suffered from being used as medieval dish and the loss of its reedbed habitat as wetlands were drained.
The bird became extinct in the UK as a nesting species in 1886 before re-establishing itself in the Norfolk Broads in 1911.
Numbers increased until the 1950s but fell again to a low in 1997, since when "intensive conservation" efforts have seen the population bounce back.
Natural England head of biodiversity Dr Pete Brotherton said: "This is an encouraging sign that we can restore and improve our wetland habitats, which bring vital benefits to both people and wildlife."
Richard Benyon, the government's minister for natural environment, said: "To see a species that was once extinct in the UK rise to a population of over 100 is a real achievement.
"This is largely down to the work of the RSPB and Natural England, and shows what can be achieved if we work together."
The conservation groups said the bittern still faced threats including sea level rise, with the risk of saltwater inundating freshwater sites along the coast.