Damage Prevention And Control Of Bats

Eviction:

Occasionally, a single bat may accidentally fly into a home, garage or other building through an open door or window. These are often lost young bats and their primary concern is to make a safe escape.

Sometimes, they will leave on their own if the lights are turned on, a window or door to the outside is opened and the others are closed.

If the bat does not leave on its own, it can be captured by waiting until it lands, and then covering it with a small box or container. A piece of cardboard should then be slipped between the wall and box and the bat can then be released outside.

Exclusion :Flying-foxes

If flying-foxes roost in backyards, they should be left alone as they are likely to move on within a few days. Flying-foxes tend to return to roost areas regularly, so it is most likely that they have been roosting in backyards, streets and parks without causing harm and without residents knowing they are present (DSE 2007).

During periods of food shortage, Flying-foxes can cause damage to stone fruit, pome fruit (apples and pears), mangoes, lychees, pawpaw, coffee and bananas, in northern New South Wales and Queensland (DEC 2004). However, in Western Australia, few reports of damage have been received by DEC.

The only legal and humane means of protecting fruit crops is by exclusion netting and non-lethal scaring techniques. Small fruit trees can be protected by stretching netting over a frame or by bagging fruit until it is harvested. Netting is also recommended for high value commercial crops.

For protection from Flying-foxes, netting must be installed correctly, monitored daily and kept in good repair to prevent the Flying-foxes from becoming entangled. Netting with a knitted mesh and a maximum mesh size of 40 mm will exclude Flying- foxes (EPA / QPWS 2005).

Thin nylon (monofilament) netting should not be used as it is easily pulled out of shape, causing the animal to become entangled. Once entangled, Flying-foxes become distressed and can break bones and tear wing membranes (EPA / QPWS 2005).

To protect trees from Flying-foxes, the netting must be kept taut by fixing it to a frame. The flying-foxes must be able to bounce off the netting and the tension must be checked daily to prevent entanglement.

If netting is not practicable, combinations of methods such as those used to deter birds (strobe lights, noise, gas guns and patrols) are the most likely to be effective (DEC 2004). As an alternative to deterring the flying-foxes and the associated cost and commitment required to prevent entanglement, landowners may simply allow the flying-foxes to take a proportion of their fruit.

Insectivorous Bats:

Insectivorous bats can roost under eaves and shingles and they can enter the living space through very small gaps of 1 cm diameter. If the bats are not causing a nuisance, there may be no need to evict them, but if they are causing problems, they can be excluded by blocking entrances and fitting one way valves.

Exclusion should only be carried out during the active season from September to late April, but should never be carried out during the breeding season from November to January. This is because dependent, non-flying young are likely to be in the roost at this time (Temby 2003).

All gaps leading to the inside of the building must be sealed using cloth, paper, corrugated iron, expanding foam etc. Entry points may be obvious by staining or droppings in the surrounding area, or on the ground.

A one-way value should then be fitted to the remaining exit point. This allows the bats to leave, but not return. There are a number of designs that can be employed, such as the one-way flap and the PVC pipe exclusion tube . The flaps may be constructed from netting or strong plastic, so that the bats are unable to grip the flap.

After the bats have been excluded from the building, droppings should be removed from the floor, ceiling and from around the entry points. A disinfectant or deodorant should also be used to clean the area. This is because the odour may attract other bats to the roosting site.

 

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