Bittern monitoring in 2010

Background and current monitoring

Following recolonisation of the UK early in the 20th century, Bittern numbers increased to a peak of about 70 booming males in the 1950s, but then fell to fewer than 20 in the 1990s, with similar declines witnessed in many other countries in Western Europe. By 1997, there were only eleven booming male Bitterns in the UK; these were mainly within Norfolk and Suffolk, but with a small outlying population at Leighton Moss, in Lancashire. This historic decline and current rarity has led to Bittern being a UK BAP species and included on the red list of UK Birds of Conservation Concern. Bittern is also on Schedule 1 of the Wildlife and Countryside Act and Annex 1 of the EC Wild Birds Directive.

Bittern, undisclosed site, Kent (Photo: Steve Ashton)

A joint RSPB/Natural England programme, funded through Natural England's Action for Birds in England, has been responsible for monitoring the numbers of UK booming male Bitterns every year since 1990. The main aims of the annual survey are:

• To report the minimum and maximum numbers of booming male Bitterns in Britain.
• To report the minimum and maximum numbers of nesting females in Britain.

Since 1997, there has been a steady increase in the number of booming Bitterns, up to a peak of 55 boomers in 2004. However, there was then a slight decline in the following two years, with 44 boomers recorded in 2006, with an encouraging increase again in 2007, to 51 booming males, and then a large jump in 2008, to 75 booming males. There was a minimum of 82 booming males confirmed in England, an increase of only 9% since 2008, but a substantial increase of 60% since 2007. The population of booming males has increased to its highest level since the monitoring programme began, and up to or even above the 20th Century peak that was reached in the 1950s.

A detailed summary of the 2009 season can be downloaded from a previous BirdGuides article.

Please contact us if you hear any booming Bitterns this year

With reedbed creation throughout the UK and a rapidly expanding Bittern population, we are increasingly reliant on landowners, site managers, wardens and local birders to report booming to us. This year, it will be very interesting to see what effect the prolonged freezing conditions this winter will have on the number of boomers and nesting attempts.

Bittern, Brandon Marsh NR, Warwickshire (Photo: Kath Everitt)