Conservation Science in the RSPB 2006

30
Andy Hay (rspb-images.com)
Installing bearded tit ‘nestboxes’ at Leighton Moss
The autumn of 2000 was the
wettest in England and Wales since
records began in 1766 and the
reedbed at Leighton Moss was
flooded for most of November and
December. At this time of year,
bearded tits feed mainly on reed
seeds, which at Leighton Moss they
gather mainly from the reed litter on
the ground. With most of this litter
under water, the bearded tits lost
their main food source and body
weights were low. The flood waters
receded during late December but
were followed immediately by 10
days of cold weather, but not of the
severity known to have caused
previous population declines.
A survey in 2001 revealed just seven
active nests, a decline of 90% on the
year before. Recaptures of ringed
birds indicated that fewer than 5% of
bearded tits survived the 2000–2001
winter, compared to 56% of adults
and 40% of first-years that survived
other winters.
The impact of this flood was severe,
causing the birds to die either through
lack of food or by being in such poor
condition that they were unable to
survive during the subsequent cold
weather. Climate change is
expected to bring wetter autumns
and winters to north-western Europe
and flooding of reedbeds could pose
an increasing threat to bearded
tit populations.
Contact:
will.peach@rspb.org.uk
Wilson J and Peach W (in press) Impact of
exceptional winter flooding on the population
dynamics of bearded tits Panurus biarmicus.
Animal Conservation.
doi: 10.1111/j.1469-1795.2006.00063.x