One of Britain's loudest but most secretive birds has had one of its best ever years - despite a fall in numbers in its East Anglian heartland.

Eastern Daily Press: Bittern numbers have increased across the UK despite recording a drop in East Anglia. Picture; John Bridges / RSPBBittern numbers have increased across the UK despite recording a drop in East Anglia. Picture; John Bridges / RSPB (Image: © RSPB-IMAGES AND ITS IMAGE CONTRIBUTORS. ALL RIGHTS RESERVED. This image is protected by international copyright laws and dist)

Bittern numbers have decreased this year in the region because of last year's drier-than-average winter, leaving some reedbeds too dry in the spring when the bird looks for nesting sites, a new study found.

Some coastal sites, such as Easton Broad in Suffolk, were also affected by flooding from the sea, which is a threat to many of the coastal freshwater reedbeds that are traditionally a stronghold for bitterns.

However, in other parts of the UK, it has enjoyed its best year since records began. The bittern, a kind of heron, is doing well following intensive conservation efforts.

They live most of their time within dense stands of reed, making them very difficult to survey. Scientists count them by listening for the male's foghorn-like booming call, which can reach more than 100db in volume.

Eastern Daily Press: Bittern numbers have increased across the UK despite recording a drop in East Anglia. Picture: Ben Andrew / RSPBBittern numbers have increased across the UK despite recording a drop in East Anglia. Picture: Ben Andrew / RSPB (Image: Archant)

This year numbers increased to at least 164, recorded at 71 sites.

That compares to 162 at 78 sites in 2016, and is a positive sign that bitterns, which were once extinct in the UK, are back from the brink and thriving.

The annual monitoring, organised by the RSPB, found that the number of booming males in Somerset increased by two, from 47 to 49 boomers.

Booming was also reported from three new sites, and there was an increase in Wales this year.

Simon Wotton, senior conservation scientist at the RSPB, said: 'In the late 1990s, the bittern was heading towards extinction once again in the UK.

'But, thanks to conservation efforts to restore and create its preferred habitat of wet reedbed, the bittern was saved and we're delighted to see another record year for this amazing bird.

'The decrease in bittern numbers in some of their traditional breeding sites highlights the vulnerability of these habitats and the importance of creating new reedbeds in areas safe from coastal flooding.'

This year, RSPB Lakenheath Fen, close to the border of Suffolk with Cambridgeshire and Norfolk, had a record eight male bitterns booming on the reserve.

Lakenheath's freshwater reedbed habitat has been specially created to safeguard bitterns against the future loss of coastal reedbeds to increasingly frequent storm surges and rising sea levels.