http://www.advocatesforanimals.org.uk/pdf/cullinggreysquirrelsl.pdf

Stephen Harris, Carl D. Soulsbury and Graziella IossaSchool of
Biological Science, University of Bristol, Woodland Rd, Bristol, BS8
1UG

SUMMARY

•Red squirrels populations have historically undergone large
population fluctuations.Causes include habitat loss and disease. At
various times in the 19thand 20thcentury,red squirrels from Europe
have been introduced to re-establish or augmentpopulations.
Genetically, red squirrels in Britain are not distinct from those in
Europe.•Grey squirrels have been introduced to various localities in
Britain. Despite culling,these populations have now spread over most
of England and Wales, and into manyparts of Scotland.

•Red squirrel populations are declining for two reasons: ecological
displacement bygrey squirrels, which may take many years, and squirrel
poxvirus (SQPV). Greysquirrels act as vectors for SQPV and aid the
spread of this disease into novel redsquirrel populations. Grey
squirrels quickly fill the vacant ecological niche when redsquirrel
populations die out from SQPV.

•It is widely argued that controlling grey squirrel numbers is the
best way ofconserving red squirrels. However, there is little evidence
to support this belief.Most squirrel control is carried out with
warfarin, but only live trapping and/orshooting can be carried out in
areas with reds.Attempts to create animmunocontraceptive for grey
squirrels have failed and no biological control methodsare currently
available.

•Most control is done within the context of protecting commercial
woodlands fromsquirrel damage. There is mixed evidence that grey or
red squirrel control worked;bounties schemes in the past have proved
unsuccessful at lowering populationnumbers. Success has been limited
to isolated populations such as islands; greysquirrels can colonize
areas quickly, so most grey squirrel control is ineffective.

•Grey squirrels can damage commercial forestry and are cited as having
a negativeimpact on woodland birds. Whilst the evidence with regard to
commercial forestry isunequivocal, controlling squirrel numbers is not
always effective and currentsilviculture techniques may exacerbate the
problem. There is at best limited data tosuggest the minor role of
grey squirrel’s impact on two species of woodland bird.These arguments
ignore damage to forestry and predation on woodland birds
thathistorically were attributed to red squirrels when they were more
abundant. Inaddition, no consideration is given to the benefits that
grey squirrels may have,including the formation of deadwood, an
important component of biodiversewoodlands

•Culling of grey squirrels could lead to more problems than solutions.
Culling maylead to an increased localised density, an increase in
forest damage levels andincrease the spread of disease.

•Red squirrel populations will continue to decline in the face of
increased ecologicaldisplacement by grey squirrels and SQPV. Novel
techniques need to be devised toprotect red squirrels. These include
setting island refugia, and developing aneffective and humane way to
eliminate grey squirrels.

•Large sums of money are being spent on red squirrel conservation.
However, thismoney is not spent wisely. Whilst red squirrels are
native to Britain, many of thepopulations are recently introduced
European stock, and so even if red squirrels doeventually disappear
from Britain, they could easily be reintroduced again. Globally,red
squirrel populations are not threatened and the conservation effort in
Britain is of little importance.