This bizarre species of bird is famous for its elusive
behaviour, strange look and characteristic call.
Bitterns are part of the Heron
family but are smaller in stature and thick set with buff-brown plumage and
dark streaks which allow them to blend in perfectly with the reeds through
which they hunt. They are notoriously secretive and difficult to see but the
breeding call can be heard from miles around. The Bitterns ‘boom’, as it is
called, is produced by the males and
sounds like someone is blowing very loudly over a glass bottle! Each sound is
unique and can be used to identify individual males.
Reedbed areas, which Bitterns
rely on for feeding and nesting, were drained for agriculture. This, combined
with persecution, led to their eventual extinction in 1885. Reedbed restoration
has allowed the birds to slowly recover in number throughout Britain. Here at
Holkham the re-wetting and re-profiling of land has created small areas of
dense reedbed and clearing dykes has improved feeding opportunities.
A bittern disguises itself in the reeds.
Bitterns are highly adapted to
live in reeds. Their large feet are used to grasp reed stems allowing them to
peer over the reed tops. They construct a nest platform in the thickest part of
the reedbed close to the water level and the female will add material to the
nest as the water level increases. Bitterns have a varied diet composing mainly
of fish, amphibians and insects.