Nature features

Bittern, Andy Hay, RSPB Images

This year’s count revealed a minimum of 46 male bitterns, compared with last year’s bumper count of 55 males, which is a significant drop.

Suffolk bitterns

The bitterns recorded in Suffolk were in five coastal wetlands which were all vulnerable to rising sea levels. The RSPB says this shows how important it is to create new freshwater wetlands to replace those likely to be lost in the future.

Habitat

The bittern is dependent upon large tracts of wet reedbed to find sufficient food, principally fish and amphibians. In the 1950s, the bittern was more common, but the drainage of wetlands and the general deterioration of reedbeds led to the decline that continued to the late 1990s.

Boom

The bittern has a distinctive booming call, with the males audible for up to three miles. Monitoring these calls enables researchers to count these otherwise secretive birds.

Norfolk bitterns

Norfolk's bittern population has suffered a significant decline, dropping from 19 males down to 11 over the same period, with the most noticeable drop occurring in the Broads.

Allan Drewitt, senior ornithologist for English Nature, said: “The record of 55 booming males in 2004 was a major achievement and fantastic news for all those working hard to establish a thriving population of bitterns in the UK.

Dr Ken Smith of the RSPB, said: “In spite of this small setback the recovery of the breeding bittern population is a conservation success story and a credit to the wide range of organisations involved.

"The European Union’s LIFE fund, which has financed a good deal of the work, deserves particular praise. However, the bittern population still has some way to go before it is secure.”

English Nature and the RSPB organise the annual bittern monitoring programme.