Reedbed management and breeding bitterns Botaurus stellaris in the UK Original Research Article

A survey of habitats at 17 reedbed sites in the UK which currently hold or have recently held breeding bitterns Botaurus stellaris has shown significant differences between sites with decreasing and sites with increasing numbers of birds over the period 1979 to 1994. Those sites where bitterns have declined had significantly higher values for variables describing scrub encroachment and the presence of wet herb species than those where the bitterns have increased. A model describing bittern numbers in 1990 at the 17 sites included reed area and a measure of scrub encroachment as the significant predictive variables. It is concluded that hydroseral succession has been a key factor in the recent decline in breeding bitterns in the UK.