TRAPPING and shooting are currently the only lawful means of grey squirrel control, but they are not always efficient or cost-effective ways of keeping populations down.

Trapping is the more efficient of the two (simply because traps work without an attendant human), but the effort involved in checking them is costly, tedious and often discouraging.

With the withdrawal of warfarin as a commercial bait in hoppers for greys, a niche market opened up for a different system. Could a novel multi-catch trap system alleviate things – and was there one around?

Look no further than New Zealand, where mankind has let loose a menagerie of alien mammals that have thrived to become pest species in their new-found home. A number of ingenious and sometimes drastic strategies have been developed to combat introduced rodents and other small mammals such as rats, stoats and opossums.

The company GoodNature has developed a range of multi-catch traps for dealing with such problem mammals.

Under the new Spring Traps Approval Orders, the long-awaited GoodNature A18 Grey Squirrel Trap was approved in England and Scotland from 1 January 2019, available for sale in the UK.

The conditions of use for the GoodNature A18 are different for each devolved country in the UK and sometimes each region too. For example, the trap would not be allowed in areas where red squirrels hang on because of the danger of by-catch.

As a self-resetting, multiple trap, it has considerable potential benefits in efforts to control grey squirrels – not least, it promises to reduce the workload considerably.

The manufacturers claim their range of GoodNature traps have revolutionized pest control – being self-resetting, toxin-free and humane. A world first, they say. Forgetting the PR and media hype, their product is certainly different. 

A GoodNature trap is not a conventional one. It isn’t a medieval-looking, metal contraption with springs and jaws. Instead, the outside casing is tough plastic, and its hidden internal mechanism is powered by the force of compressed gas (carbon dioxide) from a small screw-in cartridge. The A18 is intended to be fastened prominently to a tree at a height of around 1.5 metres. 
The closed top end houses the bait or lure. The animal only has to poke its head in from the open bottom end of the trap, trying to reach the bait inside, and brushes aside a fine wire trigger. Powered by the small compressed gas cartridge, a captive piston about as thick as a pinkie finger is released and hits the back of the animal’s head. The result: near-instant death.

The piston retracts, the dead animal drops out of the trap, and gas pressure from the reservoir resets the mechanism ready for the next unsuspecting victim.

As the name suggests, the A18 will kill up to 18 times before a new gas cartridge is needed, and the lure is formulated to be long-life too (‘A’ stands for ‘automatic’).

In most circumstances, corpses will quickly be removed from the forest floor by scavengers as they drop down. So how do you know how many times the trap has fired and when the gas cartridge needs changing?

A ‘strike counter’ attachment keeps a tally of how many times it has fired. This guides the operator as to when to replace the gas cylinder, even when he or she hasn’t seen any bodies.

Even when the count reaches the magic 18, there may still be enough gas up the spout for one last firing – so users should never poke any fingers up the tube.
Last month, the Royal Forestry Society hosted a free workshop at Battram Wood in the National Forest, when Vance Paines of GoodNature UK demonstrated the trap and how to use it to best effect. This was also a golden opportunity for the 25 participants to share knowledge and experience of grey squirrel control with other woodland managers and quiz the sellers.

This 48 ha block of multi-purpose, commercially viable woodland was established by the Royal Forestry Society between 1999 and 2001 on arable farmland in north-west Leicestershire in the National Forest, which now expands across the English Midlands.

Today, the landscape is still evolving but, like so many other woodlands across the UK, it has not escaped the attentions of the North American grey squirrel. The RFS has three bait stations in the woods where authorised local marksmen, armed with air rifles, kill about 70 squirrels a year.

After demonstrating a range of tunnel, cage, single-use and multiple-catch traps currently available in the UK, Vance Paines introduced the GoodNature A18, talking through the pros and cons of this new multi-catch device and the refinements underway.

Of course, no trap is foolproof. The lure is being refined as any trap is “only as good as the bait”. His favourite so far is hazel truffle, a paste used in the catering trade. Each trap operator tends to conjure up their own recipe. Peanut butter is a hot favourite, but should be organic for optimum results. Smearing just a little of the bait outside on the trunk can boost catch rates.

Situations will vary, but the GoodNature trap should be sited up a tree – preferably one with coarse bark so the squirrel can climb it easily – and pre-baiting may be useful. Sites with a lot of ground cover should be avoided and those with a continuous tree canopy are ideal so greys (and the trapper) can get to the trap in safety.

As the squirrel is dispatched before actually reaching the bait chamber, the amount needed is minimal and, as it’s inside and protected from the elements, it is long-lasting, though it will eventually need changing.

The gas cartridge will need replacing after 18 hits. A diode-style counter keeps the tally. In development is a counter with BlueTooth so the count can be checked from a distance – and even by drone.

The bracket mounts for the traps are sold separately so those can be left in place and just the traps moved around.

The striking orange livery can be doubly beneficial – easy for the right people to see, while attractive to inquisitive squirrels – but a simple slip-over box or coat of spray paint provides camouflage.

The company works with the European Squirrel Initiative, the UK Squirrel Accord and scientists. Traps are monitored using the latest camera technology with studies on what happens to the dead animals once they fall to the ground.

As with any vertebrate pest control (VPC), there may be a risk of non-target birds and other animals falling victims unintentionally. Any by-catch is carefully checked, but to date these have been minimal. 

Trapping greys without the cooperation of adjoining woodland owners will never be effective. Squirrels are highly mobile and disperse rapidly from a wood where they are not controlled to fill the vacuum in the one that is. A collective control crusade is called for (a similar story there to deer control).

The spread of native pine martens and their purgative effect on greys has been heralded as a natural panacea, while work on immunocontraception presses ahead, but has some way to go.

Habitat management and silvicultural practice might also help. Strange though it may seem, smearing a sap substitute such as maple sugar on sacrificial trees in a stand where squirrels are debarking or may debark valuable broadleaves could deflect attention from the main crop. The role of social behaviour and territory marking in debarking could be a factor. Improved predicting on when the often very sudden, intense yet sometimes sporadic debarking happens would assist.

The arrival of the GoodNature A18 grey squirrel trap from the Antipodes and its recent approval for use on this island is welcome. This multi-catch trap may not be the long-sought-after ‘silver bullet’ for making a dent in grey squirrel stocks as a damage-limitation exercise in woodlands in the UK and a saviour of the native reds. But it is certainly a useful addition to the armoury.

Used at the recommended density of one trap per hectare, it is not cheap initially but should be cost-effective in the longer term with low maintenance apart from the gas cartridge and bait.

And efficiency will increase as the operators’ field craft evolves and is passed on in meetings such as that organised by the RFS at Battram Wood.