Bittern numbers recovering according to research

Britain’s loudest bird, once extinct in the UK, has enjoyed its best year since records began, according to a new survey by the RSPB and Natural England.

The bittern, a threatened relative of the more familiar grey heron, has seen its population rise over the last 15 years from 11 males in 1997 to 104 this year.

Last year the survey revealed 87 males. 82 males were recorded in the previous year.

Bitterns are highly secretive wetland birds and live most of their time within dense stands of reed, making them very difficult to count. However, the males have an amazing ‘beatbox’ ability, where they fill their gullets with air which they release to make a booming ‘song’ which can be heard several kilometers away, enabling scientists to determine the bird’s population.

This summer, researchers found evidence of at least 104 ‘singing’ or ‘booming’ males, principally in East Anglia. However, the bird has also recolonised the Somerset Levels (in 2008), where surveyors found 25 males, up from 14 in 2010.

Following an intensive period of habitat management since the mid 1990s, Somerset is now the second most important county for booming bitterns in England, after Suffolk, which recorded 33 boomers. Norfolk, with 23 booming males, was third.

[pullquote]To lose the bittern once in Britain was regrettable, but to have lost it twice would have been unforgiveable
Martin Harper -RSPB[/pullquote]

The bittern has had a rollercoaster history in Britain, as the bird was extinct as a nesting species between 1886 and when it recolonised the Norfolk Broads in 1911.

The bird’s population rose once more until the 1950s when another decline brought the population to a recent low in 1997.

Natural Environment Minister Richard Benyon said: “To see a species that was once extinct in the UK rise to a population of over one hundred is a real achievement. ”

Martin Harper is the RSPB’s Conservation Director. He said: “To lose the bittern once in Britain was regrettable, but to have lost it twice would have been unforgiveable. Concern for the bittern in the 1990s led to an intensive species-recovery programme, with research and habitat improvement and creation playing major roles. Focussed work on bitterns has led to great gains for reedbeds and all the wildlife associated with this priority habitat.

“This species-led approach to bittern conservation has been vital for the recovery of the bird in England. We look forward to seeing an extension to this approach for other threatened species as a central theme in the England Biodiversity Strategy delivery plan.”

Seventeen out of every 20 English booming bitterns (85%) were recorded on nature reserves and overall almost two thirds (65%) of booming bitterns in 2011 were recorded on Sites of Special Scientific Interest.

Bittern still under threat

The bittern still faces several threats, including sea level rise, where freshwater sites along the coast could be inundated by saltwater. Additionally, a potential issue is the need for sites suitable for nesting bitterns to receive on-going management.

Dr Pete Brotherton, Natural England’s Head of Biodiversity said: “The bittern’s recovery is a great conservation achievement and shows what can be done when government, conservationists and landowners work together.

“This is an encouraging sign that we can restore and improve our wetland habitats, which bring vital benefits to both people and wildlife.”

The number of booming males recorded in the top five counties during the 2011 survey are

• Suffolk 33 (4)
• Somerset 25 (1)
• Norfolk 23 (3)
• Cambridgeshire 7 (0)
• Lincolnshire 4 (0).

(The figures in brackets refer to the figures in 1997)

The survey also recorded the number of nesting bitterns.

A minimum of 63 nest have been confirmed in England at 26 sites, compared to the low point of six nests at four sites in 1996.

With 21 confirmed nests, Suffolk was also the best county for nesting bitterns in 2011. Somerset was second with 19 confirmed nests and Norfolk was third with 11 confirmed nests.

Since the mid 1990s the European Commission has provided EU LIFE funding for two bittern conservation projects to create new reedbeds or manage existing ones. Of the 63 nesting bitterns, 37 were recorded on sites included within these projects.

The bittern monitoring programme is jointly funded by the RSPB and Natural England, through the Action for Birds in England programme.