Predation

Pioneered in the UK by the GWCT and its regional advisory team, the Larsen trap has revolutionised crow and magpie control.

Plans are available from here. Alongside the plans is a set of hints on how to use the trap, which also covers the legal aspects of Larsen trap use.

Here is a link to a sign that fits neatly onto the roof of a Larsen trap, and lends official approval to this form of legal pest control.

The licence allowing the use of Larsen traps says that the trap can be used, amongst many reasons, "for the purpose of conserving wild birds". We therefore believe that trapping magpies during the spring and summer to protect other nesting birds is perfectly legal.

Our hints on using Larsen traps cover decoy welfare and other aspects of best practice, and are available free of charge. We recommend that all Larsen trap users read them and follow the guidance.

Yes. Full details of the licence requirements for Larsen traps are given in our guidelines on how to use them.

Even experts such as our regional advisers and professional gamekeepers can rarely be definitive about what has killed birds in this way, and it is also important to remember that scavengers can often leave confusing evidence on bodies killed by something else.

Many predators are prone to surplus killing, but mink are undoubtedly one of the worst. If the birds are apparently untouched apart from pinprick bite marks and bruising at the back of the head, mink are quite likely to be responsible. Sometimes, having killed a number of birds, a mink will feed from just one, perhaps opening up the belly to get at the internal organs.

Earlier work, particularly during the Coypu eradication scheme, showed that mink are particularly attracted to floating rafts. Our predation research team decided to investigate this, and found that it is possible to place clay lined tracking pans in tunnels on rafts and detect which species of mammals are using these. Once presence of mink is detected it is possible to put a trap in place and catch the mink.

This scheme has two great advantages over existing techniques. First, it saves time since fortnightly checks are all that is needed until the traps are set, when daily checking becomes essential. Second, it reduces the chance of catching non-target species, since it is possible to trap solely on rafts where mink are the only species known to be visiting. Initial results also indicate that this method is far more effective than the normal trapping techniques.

Unfortunately, all of our work with cage traps indicates that foxes are very hard to trap in this way. Cages may work quite well in suburban situations, especially with younger animals, but we have yet to find an effective cage trapping technique for foxes in the wider countryside. We are also concerned about the welfare of cage trapped foxes.

Our experience is that they are likely to suffer painful injuries in their attempts to escape the cage. Our advisory staff can help you devise the most appropriate fox control strategy for your situation, and may be you will want to attend one of our fox snaring training courses.

Foxes and badgers have very different behaviour patterns, and this can allow a good degree of discrimination when fox snaring. However, total avoidance of badgers is difficult in areas where are lots of them.

We offer fox snaring training courses to help snare users to be more target specific, and more efficient at catching foxes.

We also publish a guidance leaflet on fox snaring guidelines.

As of April 2020, a large number of spring traps approved in the UK can no longer be used to target stoats, key examples being Fenn-type designs. Fenns may still be used to target rats, weasels and grey squirrels but consideration should be given to putting non-target species, which now includes stoats, at risk of being caught. Where stoats are present, operators should use traps that are approved for this species.

Tunnels should not be too large. If an animal can turn around in the tunnel it may not be trapped cleanly. Tunnels for spring traps like the Fenn and Springer should be just wide enough to accommodate the set trap with its safety catch off, and just high enough for the jaws to close freely when the trap is sprung. In the case of the No 4 size; this is16cm wide by 13cm high. This gives the animal less ‘room for manoeuvre’, and reduces the risk of the trap not killing to a minimum.

It is also important to set the trap well back into the tunnel, and not in the entrance. In this way your trap is less likely to deter a shy or cautious predator. Also, once the animal is well into the tunnel, it is more likely to be committed to going right through, rather than trying to turn round.