Barn Owl Trust Waterleat, Ashburton Devon TQ13 7HU Rodent Control
Tel: 01364 653026 email [email protected]This leaflet provides information on
rodenticide on wild Barn Owls. There is a concern
minimising the risks to Barn Owls whilst
that it may affect hunting efficiency and breeding
controlling mice and rats. It lists rodenticide
success. Monitoring of Barn Owl carcasses has
products, indicating which ones are less likely
shown an increase in secondary poisoning; the percentage of carcasses containing residues of
to kill Barn Owls and a non-toxic product
second-generation rodenticides increased from 5%
which is now available.
in 1983-4 to 53% in 2003 (Predatory Bird Monitoring
Scheme). In 2006 a new, more sensitive method of
analysis was used. This revealed that 63% of the
British Barn Owls mainly hunt over agricultural land but
also hunt around farm buildings - particularly in winter.
generation poison in their livers. Had the old method
Rodents, especially rats, can be a serious problem on
been used, the poison would have been detected in
farms and tend to inhabit buildings used for feed, bales,
just 39%. While this shows that levels of poisoning
or livestock. The number of rodents in and around farm
have gone down since the high of 2003, it also
buildings increases during the breeding season (in the
suggests that previous levels have been significantly
summer) and during autumn extra animals often move
underestimated. What the 2003 figure would have
in from hedgerows and watercourses. Traditionally,
been had the new method been available then can
wintering Barn Owls hunted within farm buildings and
only be guessed at. The figure for 2007/2008, again
helped to keep rodent numbers down. This also
maximised the owls’ chances of surviving periods of
severe winter weather. As farm hygiene improved the
use of rodenticides (poisons to kill rodents) became
In cases of rodenticide poisoning of non-target animals,
common. These days about 90% of farms use them.
take the victim to a vet immediately for an injection of
vitamin K1. For a poisoned Barn Owl, daily injections
Rodenticide bait usually takes the form of grain or
for 5 to 7 days are recommended (note: there is no
pellets to which the poison has been applied, and is
specific antidote to alphachlorolose or calciferol). If you
often coloured blue. There are lots of brands available
find a dead Barn Owl or indeed any animal and
with various chemical ingredients (see Tables 1, 2 and
poisoning is suspected, please telephone DEFRA
3). They are normally supplied loose, in small boxes
immediately on 0800 321600 to report the incident.
for the rodents to enter, or in small bags (scatter-
packs) and are incorporated into bale stacks, etc.
Exposure to the risk of secondary poisoning is both
There is also a product now available that is not a
frequent and widespread. The original first generation
poison but a plant-based product that kills by
types such as Warfarin (Table 1) have been
upsetting the digestive system of rats and mice and
superseded by second-generation poisons (Table 2)
is apparently harmless to other animals. Please
because rats in some areas became Warfarin resistant.
see the information box entitled Eradibait.
Due to their foraging behaviour, Barn Owls along with
Red Kites and Kestrels are far more likely to suffer
How the poisons work
secondary poisoning than any other species.
Most rodenticides are anti-coagulants - they prevent
the blood from clotting and thin it until the victim
All rodenticides listed in the tables overleaf are toxic
eventually dies from internal bleeding. The time taken
and can kill Barn Owls. However, the instructions
for a rodent to die after eating the bait varies from two
provided on rodenticide product containers do not
to twelve days. A rodent eating a sub-lethal dose (not
mention the risks or explain the mechanism of
enough to kill it) may carry the poison in its liver for
secondary poisoning in spite of the fact that these are
several months. Before a poisoned rodent dies it may
well known to the manufacturers and the government
be caught by a Barn Owl which then ingests the
who licence the products. Instructions are given to keep
poison - this is called secondary poisoning. Creatures
the bait covered up in order to protect non-target
which have been killed by secondary poisoning include
species, but this does nothing to reduce the risk of
Barn Owls, Tawny Owls and foxes. Animals which have
secondary poisoning. Recent efforts by the rodenticide
been killed by directly eating rodenticide baits include
industry to tackle misuse and the inclusion of the words
dogs, cats, pigeons and blackbirds (DEFRA).
“Harmful to Wildlife” on product labels is certainly a
step in the right direction. However, it is important for all
Research has shown that poisoned Barn Owls either
rodenticide users to be aware that secondary poisoning
die slowly or survive and carry a residue of poison in
cannot be completely prevented no matter how the
their bodies. Typically it takes 6 to 17 days for a Barn
poisons are deployed. The approved use of rodenticide
Owl to die after eating three mice containing
products (that follow the manufacturer’s instructions)
Brodifacoum. Unfortunately no research has been
cannot possibly prevent poisoned rodents being caught
carried out on the effects of a sub-lethal dose of
Barn Owl Trust - Conserving the Barn Owl and its Environment First Generation Poisons - to be used in areas Table 2 continued….
where rats demonstrate little resistance to these chemicals.
Chemical Product names Manufacturer
Killgerm Sewercide, Killgerm Chemicals Ltd
Sakarat Bromabait Killgerm Chemicals Ltd
Second-generation Poisons - to be avoided on
farms where Barn Owls are known to be present within
Chemical Product names Manufacturer
Brodifacoum Paste Rentokil Initial UK Ltd
Jaguar Rodenticide, Bell Laboratories Inc
Bromard, Bromotrol, Rentokil Initial UK Ltd
See next page for a Non-Toxic product! Barn Owl Trust - Conserving the Barn Owl and its Environment Other poisons - to be avoided on farms where Eradibait Also sold as - Growing Success Rat & Mouse Killer Chemical Product names Manufacturer NON-TOXIC PRODUCTS
þMade entirely of food-grade natural vegetable
materials with NO added toxins or artificial chemicals.
þHighly effective against rats and mice (when used
properly) and apparently safe for other species.
Deerat Concentrate Rentokil Initial UK Ltd
For more information and a list of suppliers
please visit www.eradibait.com or phone the distributors
01673 885175 References
Incidents of secondary poisoning can be reduced by adopting more sympathetic methods of rodent control.
Pesticide Poisoning of Animals: Investigations of
The Barn Owl Trust is now recommending a new
Suspected Incidents in the United Kingdom. (Annual
product which is apparently effective against rats and
Publication - Various Authors and Years). DEFRA.
mice and completely non-toxic to other animals and
Natrocell Technologies information pack. 2001.
birds (see information box). If you have a rodent
problem, please consider the following suggestions:
Newton, I., Wyllie, I. & Freestone, P. 1990.
1. Find the rodents' source of food and prevent their
Newton, I., Shore, R.F., Wyllie, I., J.D.S. & Dale, L. 1999. Empirical evidence of side-effects of
2. Remove their hiding places, block access holes
rodenticides on some predatory birds and mammals.
with stone or balls of squashed wire netting.
Pp. 347-367 in ‘Advances in vertebrate pest
3. Use non-toxic products such as Eradibait (see box)
management’, eds. D.P. Cowland & C.J. Feare. Fürth,
or alternative methods of killing such as traps, cats,
Ramsden, D. 1998. Effect of Barn Conversions on
4. If you must use poison, choose one containing
local populations of Barn Owl. Bird Study 45, pp68-76.
Warfarin or another first-generation poison as
these are less likely to cause secondary poisoning
Walker, L.A. et al. 2007. Wildlife and pollution:
than a second-generation rodenticide. To find out if
2005/06 Annual Report. JNCC: Peterborough.
rats in your area are resistant to first-generation
rodenticides visit: www.bpca.org.uk/microsite.asp?site=1113&pageid=8
Acknowledgements We would like to thank Alan Buckle, chairman for the
5. Put down the bait for a maximum of five weeks and
Campaign for Responsible Rodenticide Use (CRRU) for his
remove it after this time or sooner if the rodent
help in the revision of this leaflet. Further information on
wildlife and rodenticide use can be found at www.
6. Current disposal guidelines given by The Health
Barn Owl Trust 1989
and Safety Executive are as follows: Search for
Latest revision 2011
and remove rodent bodies at frequent* intervals
during treatment. Collect and dispose of the
The Barn Owl Trust is a registered charity dedicated to
remains of bait and any remaining rodent bodies
the conservation of the Barn Owl and its environment.
after treatment. All waste should be double-bagged
You can become a Friend of the Barn Owl Trust and
using bin liners or similar before disposal in a bin
support our work by making a regular donation. Friends
with a secure lid to prevent accidental poisoning of
receive our biannual magazine Feedback, our Annual
dogs, cats, birds, foxes and other wildlife or by
contacting either a specialist contractor or the Local
Authority where waste bins are not provided. Do
The Trust provides a wide range of free leaflets on Barn
not dispose in any other way. (*Intervals will vary
Owl related matters. For details of these and further
depending on product used; see manufacturer’s
information about the Trust and its work, please write
including a large SAE to the Barn Owl Trust, Waterleat,
7. Rodenticides are designed to kill. Treat any
statement that products can be "safely" used with
Email: [email protected] Web: www.barnowltrust.org.uk
Barn Owl Trust - Conserving the Barn Owl and its Environment
Pharmacology Table 3: Skeletal Muscle Relaxants Usual Dose1,2,3,4,5 Monthly Cost6* Comments 1,2,3,4, 5 Antispasmodics-Nonbenzodiazepine Metabolized to meprobamate, an addictive sedative-hypnotic agent. Concern over abuse and dependence. Controlled substance in some states. Recommend to avoid. Evidence does not support use beyond 2-3 weeks. Withdrawal symptoms may occur with Rare h
Stefan Sonnekus - Curriculum Vitae/CV Personal Attributes • I am a hard-working individual that enjoy taking on diverse challenges. • I can stay focused and stick to a task until the job is done. • Thoroughness is important to me and through research I equip myself for successfully completing • I strive to constantly increase my knowledge and understanding of newer technology a