Countryman
Diary - October 2008
It’s obvious from my postbag that the subject of predators
has divided reader opinion. A selection of your views are given
elsewhere and there are sensible arguments from both sides.
Also landing on my desk was a new study of data collected from
more than 2,300 blackbird nests over the past fifteen years.
It shows that blackbird nest failures are directly linked to
predation by magpies and other predators.
This new study, published by the science journal IBIS, was carried
out by scientists from the Game & Wildlife Conservation Trust
in collaboration with the University of Reading and aimed to
investigate the links between predator numbers, habitat management
and nest success in a common farmland songbird.
Dr Chris Stoate, Allerton Project Head of Research with the
Game & Wildlife
Conservation Trust, explained: “Nesting is an important
part of a bird’s life-cycle, and understanding what factors
affect the success or failure of each nesting attempt could be
important in our efforts to conserve songbirds on farmland. Predators
are ultimately responsible for the vast majority of songbird
nest failures, but we need to understand the combined effects
that predator numbers, nesting habitat and their interaction
have on nest success.”
Although blackbirds are not rare or endangered, they have suffered
moderate national declines in recent years. The fifteen-year
study took place on the trust’s demonstration farm in Leicestershire
during a period when a range of habitat improvements under agri-environment
schemes were carried out as well as a predator control regime
that formed part of a game management system. The study combined
nest and breeding population data for the species with data on
abundances of two of its known nest predators, carrion crow and
magpie.
Blackbirds were chosen because it is known that they can experience
high levels of nest failure. Researchers discovered that
eighty-nine per cent of blackbird nest failures were attributable
to nest predation by magpies and other predators. Dr Stoate adds: “A
vulnerable time for nesting birds is early in the season, before
the vegetation grows to conceal nests from predators.”
The research showed that nest survival was significantly higher
for the period with predator control than the period without,
at both the egg and the nestling stages. However, an important
additional finding was that, when densities of predators were
high, the positioning of nests influenced their survival.
Patrick White, a PhD student with the University
of Reading, analysed the data and said, “When considering
ways to improve the nest success of our songbirds, we cannot
only consider effects of predator numbers or habitat alone, but
must consider how the two interact.
“The control of nest predators may enable species like
the blackbird to nest successfully in a wider range of nest sites
within their territory, but any habitat management measures to
improve nesting cover on farmland, such as management of hedgerows
or scrub, would also help improve nesting success. We are continuing
our research on the specific effects of different agri-environment
schemes and predator removal on a range of species and this will
help to develop more effective conservation measures in the future.”
Hedgerow boost
A wildlife charity, the People's Trust for Endangered Species,
has launched a new competition for farmers and landowners to
reward active conservation of hedgerows. These iconic features
of our landscape support a huge variety of native wildlife, such
as the hazel dormouse and other vulnerable species, yet their
decline is widespread. ‘Reconnecting the Countryside’ aims
to highlight the importance of hedgerows as both habitats and
wildlife corridors, whilst celebrating the efforts made by the
farming community to protect them for posterity.
For the hazel dormouse, good quality, species-rich hedgerows
provide not only a habitat in themselves, but also a source of
food and a means of dispersal between other areas of woodland
habitat.
Unsympathetic management of hedgerows therefore, can
have a disproportionate impact on the local dormouse population
which may become isolated.
‘Reconnecting the Countryside’ seeks to encourage
farmers and landowners to link wooded areas to create the largest
possible continuous cover of dormouse-friendly habitat by planting,
coppicing and/or filling in gaps in existing hedges. For a ‘Reconnecting
the Countryside’ entry pack, or for more details about
the competition, contact the trust on 020
7498 4533 or e-mail
enquiries@ptes.org.
Habitat conservation
Devon Wildlife Trust (DWT) has restored traditional grazing
to Bursdon Moor, near Hartland. The move will help conserve the
important wildlife that this rare culm grassland habitat supports.
Bursdon Moor Site of Special Scientific Interest is one of the
largest remaining areas of culm grassland in the country. The
wildflowers and grasses growing in this species-rich grassland
are a reflection of soil composition and past management practices.
The project will help to conserve many threatened species, particularly
the rare marsh fritillary butterfly which has declined by sixty-six
per cent since 1990.
DWT’s Working Wetlands Project Manager, Peter Burgess,
said: “This has been a major undertaking and we would like
to thank all the supporting organisations for their help in making
this happen. The marsh fritillary last bred in an area which
has been cut-off from the rest of the moor by the busy A39. With
careful management by the commoners, involving burning and grazing,
the grassland can once again support these beautiful butterflies.”
The Working Wetlands project is supported by the Tubney Charitable
Trust, South West Water, Devon Waste Management, Grantscape and
Natural England. For more information about the project call
the Working Wetlands team on 01409 221823.
Winners
The winners of our cheese competition in July are: Mrs Storey,
Stevenage; Martin Broadribb, Tutshill; Wendy Murkin, Caterham;
Paul Durham, Cuddington. Thank you to all those who entered.
Paul Jackson |
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