Bats Need Protection
South Africa has 56 recorded species of bats. Of the 74 species found in the sub region of southern Africa, 20 species of insectivorous bats and 2 species of fruit-eating bats are listed as Threatened in the IUCN Red List of Threatened Animals. Of these 9 are listed as either Critically Endangered, Endangered or Vulnerable, meaning that they face a high risk of extinction in the wild.
The survival of bats is threatened
Because bats have low reproductive rates, populations are very susceptible to elevated mortality or depressed recruitment. There is scientific concern about the conservation status of bats as many species of bats are increasingly affected by multiple actions of humans such as ignorance, suspicion, pesticide poisoning, roost destruction and closure, habitat loss, over-exploitation, and extermination as pests. Avoid disturbance of bats in caves, including the lighting or use of fires in caves.
Some bats have moved into residential areas because human expansion has resulted in loss of habitat, forcing bats to look for alternative roosts in which to live and raise their young.
Dispelling the Myths
An uncontrollable, irrepressible fear of bats may exist, but it is often the result of centuries of prejudice, misinformation and ignorance about bats. Dracula and other horror stories have contributed greatly to these misconceptions causing people to fear them and therefore be unconcerned about their conservation.
- The incidence of rabies is rare.
- Bat droppings in buildings usually are not a source of Histoplasmosis.
- Bats are not filthy and will not infest homes with dangerous parasites.
- Bats are not aggressive and will not normally attack people or pets.
- South African bats do not feed on blood. (Vampire bats, which do feed on blood, live in Latin America.)
Although bats are extremely beneficial and help maintain balance in our delicate ecosystem, there are times when bats become a problem or nuisance to home or business owners. An understanding of the habits of these beneficial animals can help solve problems that sometimes develop when bats roost in buildings. Bats living in buildings do not cause structural damage nor do they chew on wires or wood.
Why not exterminate?
Hiring an exterminator or "doing it yourself” may seem like the simple solution. Consider these thoughts before attempting any exterminating:
- Chemicals that kill bats are also hazardous to humans and pets. All chemical usage on bats is illegal.
- Some bats will assist in insect control like devouring mosquitoes.
- It will ultimately fail because the roost is still available for other bats.
- Bats are protected by provincial legislation.
- It is inhumane when better options exist.
- Some services will offer to catch and release bats far away, but bats have been proven to return from up to 600 kilometres away – a few weeks later they will be back.
- Sealing the structure while providing an alternate roost (a bat box) is the permanent solution.
Should you bat-proof your house?
There is little reason to evict bats from buildings where they are not causing a nuisance. However, bats should be prevented from entering human living quarters and in some instances, noise or odours from large colonies of bats can become a nuisance.
Before deciding, make sure that your fears are not unwarranted!
It is best to evict and implement exclusion methods in South Africa between February and May.
Never try to evict bats from their roosting places during the following periods:
- In winter during hibernation. They won't be able to fly far to find new roosts, cannot forage and due to exposure, will die.
- During the maternity period from middle September to the end of December. This is when new babies are born and nursed by their mothers. Babies can't fly and if you evict the adults, the babies being trapped inside, will die and create an odour problem.
Exclusion and Eviction Methods
- Inspect your house for markings, droppings or physical presence
A simple inspection of the outside of the building can be made to determine whether bats are living in. Bats usually enter a building at the roof/wall joint, under loose fascia boards, or through broken vents or other cracks resulting from building deterioration. Some bats can crawl through openings as small as half a centimetre.
- Watch out for bats leaving their roosts at dusk.
The bat watch should be started about 30 minutes before dusk. Station enough people around the building so that the entire roof and wall area can be kept under constant observation. If bats are present, they will start leaving the building about dusk; the last bat should come out of the building within one hour of the first bat. All bat exit and entrance points should be noted, as well as the number of bats. This procedure may take several evenings to accomplish, but it is important to identify all bat holes.
- Plug or seal exit holes – February to May.
If only one exit/entry hole is found in the course of the inspection, it can be plugged as soon as the last bat leaves the roost (hence the reason for counting the bats). If several holes are identified, all but one of them should be plugged during the daytime. Wait a day or two to give the bats a chance to get used to using the last opening, then plug it as soon as the last bat has left in the evening.
- One-Way Valves
An excellent way to plug an entrance hole is to install a bat-proofing valve. This device, which consists of a rigid base tube with a pliable outer sleeve attached, is placed over the entrance hole, allowing bats to exit the dwelling but not to re-enter.
- Using 'One-Way' Netting to Exclude Bats
Bats sometimes enter buildings through openings on smooth surfaces of exterior walls or through louvers. In such cases, plastic or lightweight, flexible netting with 0.4 cm mesh or smaller, should be secured to the building along the top and sides of the opening to allow bats to exit the building, but not return.
After this has been done, watch to make sure the bats are able to exit safely. If they do not appear to be exiting, or appear to be having trouble doing so, make adjustments or add new valves as needed.
- Using PVC Pipes to Exclude Bats
There are a number of situations in which tubes work best as bat exclusion devices. Examples include openings used by bats on buildings constructed from materials that do not create smooth exterior walls, such as those found on brick or stone houses, and log cabins. Tubes also work best for holes located at corners where walls meet and on horizontal surfaces.
Exclusion tubes should have a 5 cm diameter and be approximately 25.4 cm in length. Exclusion devices can be made from PVC pipe or flexible plastic tubing. Use of a flexible plastic tube makes it easy to either squeeze one end of the tube so that it fits into a crevice, or cut one end of the tube into flaps that can be fit over an opening and stapled, nailed, or taped to the building. Bats are unable to cling to the smooth surface of these tubes. Once the tube has been inserted over the hole, a piece of light weight, clear plastic can be taped around the end of the tube that projects to the outside to further reduce the likelihood of bats re-entering, though this is typically not necessary.
Bat-proofing has two potential drawbacks.
One is that exclusion can be stressful for a maternity colony. When prevented from using their usual roost, the bats may move into a nearby building, where they may be expelled again, or even exterminated. Also, research has shown that displaced colonies will not relocate into buildings that already house other maternity colonies. In other words, an excluded colony cannot just move down the road into a barn or church that already has bats. If a displaced colony cannot find a new roost, it may leave the area. In fact, researchers have found that expelling bat colonies can contribute to serious declines in local bat populations.
A second drawback is that homeowners may find it difficult to bat-proof their home completely. Bats can crawl through cracks as small as 0.5 - 1cm, so persistent bats may find a way to re-enter their former roost.
Bat boxes can solve both of these problems because they provide alternative roosting sites for maternity colonies. When constructed properly, bat boxes can serve as suitable places for females to raise their pups. With bat boxes, the bats get a safe roosting site outside the home, while homeowners benefit from the bats' control of insects.
What to do if you find a bat
Many people come across young, injured or grounded bats and wonder what to do with them. Care and caution should be exercised and such cases should be referred to the nearest bat interest group, rehabilitation centre or the SPCA.
It must be stressed that bats should not be handled by the general public. Do not kill the bat – it may be the last one of his species.
A bat found indoors is most likely to be a crevice-dwelling species. These bats are often lost youngster or babies that cannot fly or migrating bats that do not know how to find their way outdoors. They may be roosting somewhere in a small part of your home, most likely up high, like a crawl space, attic or perhaps between the crawl space roof.
The following steps will help your bat guest find its way outdoors.
- Close any doors you can to contain the bat in a single room or space.
- Open all the doors and windows as wide as you can in that room or area.
- Turn any outside lights on, e.g. the porch light.
- Turn the lights in the room off or down.
- Stay in the room, sit down, relax, and watch the bat. If you don't, you will not know if it actually left or has landed and is resting somewhere.
- Do not try to guide the bat with a broom, tennis racket etc. You do not need to cover your head; it does NOT want to get in your hair.
- The bat, if allowed to, will navigate its way out using the light outside and the draft created by the open window or door. This may take 20 minutes.
If the bat has landed somewhere, it may be captured and released outside after sunset. Approach your visitor very slowly and quietly. NEVER TOUCH THE BAT with your bare hands. Gently place a can or box over the bat, slide cardboard underneath and release your visitor out of doors at dusk, placing it on a high surface where it will be able to take off.
Bats that are in good health should be released as soon as possible (during dusk) and as close to their area in which they were found as possible. If a bat has simply fallen out of its roost after being disturbed, it can be placed straight back into the roost. Bats cannot take off directly from the floor but need to be able to drop down for a distance before beginning to fly.
Bats found during hibernations should not be woken as waking requires a huge amount of energy which may be more than the bat can afford to survive.
With acknowledgement to the Gauteng and Northern Regions Bat Interest Group (http://www.batsgauteng.org.za/)
Updated: 26 November 2012