approach to the corvidae which are currently
plundering our songbird populations.
I have oft times criticised the RSPB for seemingly
'sitting on its hands' with this matter and
consequently, I shifted my financial support
Songbird Survival.
Here is a part of my reasoning:
Corvid control can improve fledging
success of farmland hedgerow-nesting
birds. Songbird Survival.
NEW research undertaken by the Game
& Wildlife Conservation Trust (GWCT)
shows that predation control of corvids
can improve the breeding success of
farmland hedgerow-nesting songbirds.
& Wildlife Conservation Trust (GWCT)
shows that predation control of corvids
can improve the breeding success of
farmland hedgerow-nesting songbirds.
Scientists at the Trust carried out a large
field experiment between 2011 and 2014,
which is described in a recently published
scientific paper. Over the four years, they
worked with farmers and estate managers
in southern England at 32 paired sites each
around 4 km2 in area, studying four different
pairs per year.
field experiment between 2011 and 2014,
which is described in a recently published
scientific paper. Over the four years, they
worked with farmers and estate managers
in southern England at 32 paired sites each
around 4 km2 in area, studying four different
pairs per year.
At random within each pair of sites, crows
and magpies (corvids) were removed at one
site by gamekeepers or other trained staff
during the breeding season using best-practice
trapping techniques; no removal took place
at the other site. The nesting success of
breeding birds was measured by the GWCT
research team using a new fledged-brood
counting method.
and magpies (corvids) were removed at one
site by gamekeepers or other trained staff
during the breeding season using best-practice
trapping techniques; no removal took place
at the other site. The nesting success of
breeding birds was measured by the GWCT
research team using a new fledged-brood
counting method.
The key finding was that overall nest success
of the hedgerow-nesting songbird community
was down by 10 per cent in non-removal
sites on average relative to removal sites
over the four years. Excluding 2012 data
because of exceptionally high spring rainfall
that year, in the other three years nest success
was down 16% in the non-removal sites on
average relative to removal sites.
of the hedgerow-nesting songbird community
was down by 10 per cent in non-removal
sites on average relative to removal sites
over the four years. Excluding 2012 data
because of exceptionally high spring rainfall
that year, in the other three years nest success
was down 16% in the non-removal sites on
average relative to removal sites.
Previous research has indicated that, in these
habitats, corvid control benefits songbirds.
habitats, corvid control benefits songbirds.
Lead scientist on the experiment Dr Rufus
Sage, head of lowland game bird research
at the Trust, said: “We know that corvids,
particularly crows, can reduce breeding
output in some ground-nesting birds. Our
field experiment indicates for the first time
that controlling corvids can improve breeding
success in hedgerow-nesting songbirds as
well. For some, but not all, species this can
affect population size. We suspect (but did
not show) that magpies are probably more
predatory of hedgerow-nesting songbirds
than crows because they are smaller and
more adept in this habitat.”
Sage, head of lowland game bird research
at the Trust, said: “We know that corvids,
particularly crows, can reduce breeding
output in some ground-nesting birds. Our
field experiment indicates for the first time
that controlling corvids can improve breeding
success in hedgerow-nesting songbirds as
well. For some, but not all, species this can
affect population size. We suspect (but did
not show) that magpies are probably more
predatory of hedgerow-nesting songbirds
than crows because they are smaller and
more adept in this habitat.”
Conservation of farmland songbirds is an
important issue because of ongoing population
declines and is fully in line with Defra
Secretary-of-State’s stated intent for future
support of farming, post-Brexit.
important issue because of ongoing population
declines and is fully in line with Defra
Secretary-of-State’s stated intent for future
support of farming, post-Brexit.
And GWCT has led the way in devising a
scientific experiment to investigate the
impact of corvid predation on lowland
farmland songbirds.
scientific experiment to investigate the
impact of corvid predation on lowland
farmland songbirds.
Robert Middleditch, chairman of SongBird
Survival, said that the charity was delighted
to have commissioned this project.
Survival, said that the charity was delighted
to have commissioned this project.
He said: “It has been a major undertaking,
carried out over several years, so we would
like to thank all those farmers, land
owners/managers and fieldworkers who
have helped contribute to the success of
the project, and our members and donors
who funded it.
carried out over several years, so we would
like to thank all those farmers, land
owners/managers and fieldworkers who
have helped contribute to the success of
the project, and our members and donors
who funded it.
“Predator removal experiments are
acknowledged by many researchers as
the best way to obtain evidence of whether
predators limit the breeding output of songbirds.
Evidence that songbird breeding success
was limited by predation was felt by some,
previously, to be weak. These research
findings provide clear evidence that corvid
control can increase hedgerow songbird
breeding success.”
acknowledged by many researchers as
the best way to obtain evidence of whether
predators limit the breeding output of songbirds.
Evidence that songbird breeding success
was limited by predation was felt by some,
previously, to be weak. These research
findings provide clear evidence that corvid
control can increase hedgerow songbird
breeding success.”
SongBird Survival - an environmental bird
charity that commissions research into the
decline in Britain’s songbirds - funded the
project.
charity that commissions research into the
decline in Britain’s songbirds - funded the
project.
Full link to paper here: http://www.bioone.org/doi/full/10.2981/wlb.00375
Notes for editors
The JNCC Farmland Bird Index, which
includes many of the songbird species in
this study, is down by 56% since 1970. It has
continued to fall in recent years but at a
reduced rate.
includes many of the songbird species in
this study, is down by 56% since 1970. It has
continued to fall in recent years but at a
reduced rate.
According to BTO Breeding Bird Survey
Trends, magpie numbers doubled between
1970 and 1990 but have remained more
or less stable since then. Crow numbers
have doubled since 1970 and continue to increase.
Trends, magpie numbers doubled between
1970 and 1990 but have remained more
or less stable since then. Crow numbers
have doubled since 1970 and continue to increase.
The decline in the Farmland Bird Index is
thought to have been caused mainly by
changes in farming practices. However the
continued decline, despite the widespread
adoption of Environmental Schemes in
recent years, suggests that other factors
such as increased predation may be involved.
thought to have been caused mainly by
changes in farming practices. However the
continued decline, despite the widespread
adoption of Environmental Schemes in
recent years, suggests that other factors
such as increased predation may be involved.
The Game & Wildlife Conservation Trust –
providing research-led conservation for
a thriving countryside. The GWCT is an
independent wildlife conservation charity
which has carried out scientific research
into Britain’s game and wildlife since the
1930s. We advise farmers and landowners
on improving wildlife habitats. We employ
22 post-doctoral scientists and 50 other
research staff with expertise in areas such
as birds, insects, mammals, farming, fish and
statistics. We undertake our own research
as well as projects funded by contract and
grant-aid from Government and private
bodies. The Trust is also responsible for a
number of Government Biodiversity Action
Plan species and is lead partner for grey
partridge and joint lead partner for brown
hare and black grouse.
ISDN radio broadcast line - at our Fordingbridge
HQ we have an ISDN radio broadcast line,
allowing us to conduct interviews remotely.
HQ we have an ISDN radio broadcast line,
allowing us to conduct interviews remotely.
For information, contact:
Joel Holt
Telephone: 01425 651000
Email: press@gwct.org.uk
Joel Holt
Telephone: 01425 651000
Email: press@gwct.org.uk
Blogger: And if this can work on farmland
and hedgerows, why not in cities too? From
the evidence of my eyes, in my own postcode,
it is magpies which are the most devastating.
and hedgerows, why not in cities too? From
the evidence of my eyes, in my own postcode,
it is magpies which are the most devastating.
Jays are fewer in numbers but also rob songbird
nests with ruthless efficiency.
nests with ruthless efficiency.
I suspect that it is with ground-nesting birds where
crows come into their own!
crows come into their own!
