Grey Squirrel control to prevent bark stripping of native trees:

5 years experience using Kania 2000 trap

Why control Grey Squirrels?

• Introduced Species [1876 from North America] that can now be found living in densities of up to 8 -16 per hectare in broadleaved woodland.

• Threat to native Red Squirrels and other wildlife

• They strip the bark from trees.

Bark Stripping

• End of May to end of July

• Young trees, 15-20 years most vulnerable.

• Particularly Beech and Sycamore.

• Can completely kill tree or lead to stunted trees that will never reach natural maturity.

• Older trees [+40 years]creates wounds leading to branch failure [majority of all tree surgery required is the result of old squirrel damage!]

Why do squirrels strip bark?

• Discard outer bark and eat unlignified tissue beneath [implies is a feeding habit?]

• Frustrated males/juveniles

• Population density, associated with 5+/ha

• Not a major problem in their native North America!

• A lack of natural predators.

Only thing you can say for certain is that this squirrel won’t be stripping any more bark!

Other methods of Grey Squirrel control

• Warfarin poisoning by baited hoppers

• Shooting

• Live trapping

The Kania 2000 spring trap

• Developed in Canada in the early 1980’s

• Approved for use in the UK in 1993

• In 2007 started to experiment with the Kania 2000 trap

Using the Kania 2000

How does it work?

Pre-baiting

• Up to at least a week before setting traps.

• Dramatically reduces trapping time as squirrels get used to eating at/around the trap.

• Pre-bait twice during the week [beginning and middle of week]

Baiting the traps

Locating traps in woodland with regards to the Public

• MUST be fastened up trees well out of reach.

• Choose trees that aren’t easy to climb.

• Try to locate where not easily seen by the public.

• Can paint green to camouflage.

• Attach warning labels.

Locating traps in woodland with regards to ease of trapping

• Make them visible from a route that you can drive [perhaps with aid of binoculars].

• Location of traps can be trial and error. Tree species and/or size doesn’t seem to matter.

• Average of 1 trap/hectare.

Trapping

• Check traps at least once per day [volunteers?].

• Use ladder and climbing harness with long strop/prussik loop.

• Set/unset trap with it firmly secured up the tree.

• Re-bait with fresh bait regularly.

When to trap?

• 2007: Experimented with setting just one trap in our compound for a few weeks in July and caught 11 squirrels!

2008

• Set 13 traps in 14ha of mature woodland from 13th Feb to 29th April.

Males Females

26 23

Total : 49

Then June 2008 saw some of the worst squirrel damage for years!!!!

So what went wrong??

• Even though we probably wiped out the entire resident population by the trapping earlier in the year we failed to appreciate just how quickly squirrels can re-colonise an area! •Squirrels are extremely mobile and studies have shown that they can re-colonise even an isolated woodland within three months and non-isolated woodland within one month!

Timing is crucial

• Trapping too early in the year will allow squirrels in neighbouring areas to move in before the beginning of the stripping period.

• Trapping too late may not allow enough time to reduce the population sufficiently to prevent damage.

2009 trapping season

• From 11th March to 31st March and 28th May to June 15th. [74 squirrels] • Resulted in no squirrel damage during the 2009 stripping season!

2010 trapping season

• From 19th April to 23rd June.

Males Females

67 41

Total : 108

2011 trapping season

• From 7th March to 12th April and 31st May to 30th June.

Males Females

54 23

Total : 77

2012 trapping season

• From 28th March to 30th April and 8th June to July 26th. [108 squirrels]

Advantages of the Kania 2000 trap • You know exactly how many you are killing.

• Appropriate for sites with high visitor numbers.

• Can be used in areas of trees that are highly susceptible to bark stripping.

• Humane non-chemical method of control

• It works! In the last 4 years have only spent a total of 6 ½ months trapping yet caught nearly 400 squirrels and there has been virtually no bark stripping!!

Disadvantages of the Kania 2000 trap

• Time consuming: 2 ½ months trapping per year [May – Mid July].

•Requires two people [ladder and harness]

•Very expensive if use contractors.

• Public may find unpleasant

•Trapping of non target species.

Non target species

2010 : [108 squirrels] but also 4 Jackdaws and 3 Great Spotted Woodpeckers!

• Traps modified for 2011

2011 : [77 squirrels]1 Jackdaw and on the last day of trapping 1 Great Spotted Woodpecker!

2012 : [108 squirrels] No Great Spotted Woodpeckers, though 1 crow and 1 Magpie

To Conclude: The Kania 2000 trap

• An effective way of controlling grey squirrels.

• Only real disadvantage is cost [contractors]. Is more expensive than other control measures, but these are usually not effective!

• Woodland managers need to re-prioritise resources.

Final comment • If there isn’t a concerted effort to control grey

squirrel numbers then there won’t be any native woodlands in the future of the type that we so love and cherish today!

Any questions? Any questions ?