Book: Fencing Chapter: 9 Fencing ­- special uses Section: Rabbits, badgers and foxes Metadata: Details Buy this book

RABBITS

Rabbits eat 30% of their body weight each day, and are a serious pest to forestry, farming and horticulture. The loss to agriculture is estimated at £120 million each year. In the 1950s, myxomatosis virtually wiped out the rabbit population, but numbers are now at 30% of the pre-myxomatosis level, and rising. For new woodland planting, the problem is particularly bad on ex-agricultural land, where rabbit numbers are often high.

Rabbits cause damage in the following situations:

1. Newly planted trees are vulnerable to damage from rabbits browsing on the leaves and shoots, and by stripping the bark. Browsing is more common and serious than bark stripping. Damage is most severe in winter and early spring, especially during snow when other food is scarce. Damage normally occurs from ground level up to about 540mm (21"), but will be higher when snow is lying on the ground. Trees up to about 10 years old are vulnerable to bark stripping, especially those with smooth bark such as ash and beech.
2. Natural regeneration of trees and shrubs may be prevented by browsing and bark stripping. This is damaging where it prevents desirable regeneration in woods and other habitats.
3. Coppice re-growth is vulnerable in the first part of the growing season after cutting. Rabbits are most likely to be a problem for intensive coppice such as short rotation coppice for energy production. For other coppices, deer are normally more severe a problem than rabbits.
4. Agricultural and horticultural crops, such as cereals and vegetables, can be severely damaged by the grazing of rabbits.

Newly planted trees and natural regeneration can be protected by individual guards, or by rabbit-proof fencing to enclose the area. The choice will depend on the density of planting and the perimeter to area ratio, which affect the relative costs of guards and fencing. Other factors such as access may also be important. For details see special uses.

It may be too expensive to enclose completely the area you wish to protect, or to enclose the infested area. Adult rabbits rarely move more than 200m from their burrows, and often move along well-defined paths. In situations where the crop is vulnerable on only one or two sides from attack, a rabbit-proof fence along this line will give sufficient control. Extend the fence 150m at each end beyond the vulnerable area.

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Hexagonal wire rabbit netting

The Forestry Commission recommend the use of hexagonal rabbit netting of the following specification: 1050mm (height) x 31mm (mesh size) x 18g (thickness of wire). The 31mm measurement refers to the diagonal, as shown. If measured vertically, the mesh size is large enough for juvenile rabbits to get through, which are capable of starting a new colony. The thinner 19g wire is not thick enough to stop a heavy infestation of rabbits, as they will chew through it. It's also important that the wire gauge is measured before galvanising, and that the galvanising is evenly coated (see materials). Some imported netting may have thinner wire, uneven mesh size and poor galvanising.

The old British Standard BS 1485:1983 (now withdrawn and superseded by BS EN 10223:1998) included the specification given above. Some wire manufacturers are still manufacturing to BS 1485. Others manufacture to BS EN 10223:1998, in which the mesh size is measured between the twists as shown below. Check before purchase that the mesh is no larger than 31mm between the wider parallels. Note that dimension B tends to widen, and dimension A tends to narrow, if the netting distorts.

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The bottom 150mm (6") of the netting must be turned in the direction of attack, and pegged down with loops of wire or covered with turf or soil. The netting works at ground level because the rabbits try to dig immediately next to the vertical barrier, and don't learn to burrow 150mm (6") back! Netting 1050mm height is recommended, to leave a fence 900mm high. For lesser levels of protection, 900mm height netting can be used, leaving a fence 750mm high. However, if this sags over time, the fence will no longer be rabbit proof. High tensile line wires to support the netting are recommended for all but the shortest lengths of rabbit fencing, to ensure that the fence stays taut.

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Wire netting has a useful life of about 10 years, before the galvanising breaks down and wire begins to rust, particularly at ground level. Coated netting (Sentinel Green rabbit netting) is claimed to have a longer life, and may be worth considering where long-term protection is needed. Badgers can dig through wire netting, and make it accessible for rabbits. Install a badger gate, or use electric fencing, which normally deters badgers.

Electric fencing

Electric netting or electrified line wires, designed specifically for rabbit control, are both effective against rabbits. To be effective, fences must be electrified the same day they are erected. Electric fences are suitable for protecting crops, young trees and coppice regrowth where there is regular maintenance to keep the fence free of vegetation, and where there is an absence of vandalism. Electric systems can be moved from one site to another, which is useful in many circumstances. If properly looked after, electric netting or wire systems have a useful life of about ten years.

Several manufacturers supply electric netting and line wire systems. Electric wire systems are more durable, and less of a hazard to non-target species including frogs, toads and hedgehogs. Netting is quicker and easier to erect. Netting must always be electrified when it is in position, as if animals are not deterred from touching it they are very likely to get entangled. Rabbits may chew through netting when it is not electrified. Wire rather than polywire is recommended for line systems, as polywire is also liable to be chewed.

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A 7 wire system is recommended for protection of high value vegetable and horticultural crops, and a 4 wire system for cereal crops (Rappa Fencing Ltd).

Two types of Flexinet netting are available. The 50cm (20") high netting is designed to protect grasses and cereals, with the 76cm (30") high netting, with smaller mesh, giving added protection for high value vegetable and horticultural crops. Both nets are available in 25m and 50m lengths.

Similar systems are available from other manufacturers, including Hotline (AEC Electric Fencing Ltd) and Rutland (see suppliers).

Gates

Pedestrian gates can be made rabbit proof by installing a solid sill of concrete, metal or wood, which extends about 300mm (12") below ground, and leaves a clearance gap no larger than 31mm (1¹/₄") between the top of the sill and the bottom of a rabbit proof gate.

Vehicle gates are more difficult to rabbit proof, as the gate has to be hung very accurately to leave only a 31mm (1¹/₄") gap between the sill and the bottom of the gate, whilst still opening freely. For infrequently used gates, attach a length of rabbit netting to the bottom of the gate to cover the gap and fold in the direction of attack, then lift up as necessary when opening the gate. A concrete sill is recommended.

Pedestrian step-over rabbit proof gates are available from Centrewire Ltd.

BADGERS

Badgers move around at night between sets, watering places, latrines and feeding sites, often on tracks that have been in use for many years. Badgers are very strong, and can push their way underneath or between tightly strained wires and stock netting, and can break through hexagonal mesh. Tracks should be easy to recognise. Look for tunnels, 150-300mm (6-12") high, through hedges and scrub, bare scuffed ground beneath fences, and clearly defined paths across permanent pasture that look like narrow footpaths, but lead to badger-height gaps in boundaries.

In many situations there may be no need to make any special provision, as even if new fences are put across the tracks, badgers will find their way through, although possibly damaging the fence to some degree. Problems arise when:

1. Gaps forced by badgers make the fence no longer stock proof, for example allowing young lambs through.
2. Badger gaps make the fence no longer proof against pest species, in particular allowing rabbits into newly planted woodlands. This requires either totally excluding badgers, or fitting badger gates or protecting the trees by other means such as tree guards.
3. Badgers themselves cause damage. This can be a problem with high value agricultural crops, horticultural crops, nurseries and gardens. Badgers cause damage by digging holes to get at worms and slugs.
4. Badgers crossing motorways or other busy, fast roads are liable to be killed, as well as causing accidents. Badger-proof fencing is necessary at vulnerable sites. In some places fencing has been combined with tunnels under the road to give badgers safe passage.

Badger-proof fencing

As badgers can get under a fence by digging, badger-proof fencing has to extend below the ground in the direction of attack. Tornado manufacture a range of high tensile netting specifically against badgers, of which the bottom 58cm (approx. 2') is designed to be buried. The section which is buried has very close horizontal wires only 83mm (3") apart, and all the vertical wires are 80mm (3") apart, to provide the strength necessary to resist a badger.

Sizes available are as follows:

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For explanation of coding, see materials.

The netting should be curved out in the direction of attack, as shown.

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Alternatively, use heavy grade chain link, with a mesh size of 50mm (2"), of sufficient height so that the bottom 600mm (2') can be buried in the direction of attack, as shown above. Lightweight chain link and hexagonal mesh are not strong enough to use against badgers.

Badgers are deterred by electric netting or line wires, of the types used against rabbits. However if they do try and break through, they are likely to damage the fence, and in particular, get caught in the netting.

Badger gates

These can be included on badger runs that cross a fence line, to allow access for badgers but exclude rabbits.

On new fences, the badger gate must be assembled in stages, to allow the badgers to get used to using the gap, before the gate is fitted. On existing fences where the gap is already in use it may be possible to proceed a little more quickly, but it should still be done over a few days.

Work is best done in early summer when badger activity is high, and in the season before young trees are planted.

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1. Erect the new fence, cutting away a piece about 200mm (8") across and 270mm (11") high in the rabbit netting. Disguise the bottom line wire by putting sods of earth beneath it, and loose earth over it. Leave this for a week or so, until you are sure it is being used. Check by looking for footprints in the loose earth, by placing a small stick across the hole (though this may be dislodged by other animals), or by watching. In early to mid summer badgers emerge regularly at dusk, and if the run is near a sett you are fairly certain of seeing them.
2. Fit the floor block in position, stapling the line wire to it. Cover this with loose earth and leave for a week or so, and check it is being used.
3. Fit the uprights and lintel, and staple the netting in place. Leave for a week or so.
4. Fit a free-swinging, temporary wooden half door, about 120mm (5") high. Leave and check for use.
5. Fit the full door, and check for use.

Foxes are recorded as using badger gates, but rabbits apparently either do not learn the trick, or are not heavy enough to push the gate open.

FOXES

Foxes can cause serious losses of poultry, game birds, lambs and piglets.

Hexagonal wire netting with a mesh size of 25mm (1") is used for making runs and enclosures for poultry and game birds. This mesh size both prevents chicks escaping, and prevents predators from getting into the run. Where chicks are enclosed, the run may need roofing in against magpies and other predators. The larger mesh size of 50mm (2") is suitable for runs which do not enclose chicks. Netting of 1.5m (5') or 1.8m (6') height should be used, to enclose the birds and prevent foxes jumping over.

Hexagonal netting with a 100mm (4") mesh is suitable for lamb pens, and is available in heights up to 1.2m (4').

For larger areas, electric fencing is the best method of deterring foxes. Various systems are available, which should be chosen according to the stock enclosed. Electric netting, such as Flexinet poultry netting, has a small mesh for better security against foxes, and to make it suitable for separating different flocks of poultry. The netting is 1.07m (42") high, with verticals 7cm (3") apart, and 11 horizontals which are closer spaced towards the bottom.

Systems of electric line wires are available to contain poultry or pigs, and to deter foxes. Rappa recommend a 9 line fox boundary fence for pig runs and boundary poultry fencing, and an 8 line internal fence for poultry sub-division fences.

PHEASANT FRIENDLY FENCING

This netting (HT6/83/22), available from Tornado, is designed to restrict stock, whilst allowing the passage of pheasants into coverts and woods.

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