Vlermuise in die dak

Vraag:
Ek het 'n probleem met vlermuise in my dak, die goed knaag aan die kragdrade en dit veroorsaak dat ons krag kort-kort uitgaan. Hoe kan ek van hulle ontslae raak? - Mindi (mindi@ese-sa.co.za)

Antwoord:

My advice (rather lengthy!) to people who phone in about having bats in their roofs is the following:

People often confuse bats and rats. The presence of bats and noises in one's roof are not necessarily related. Bats are highly specialize mammals (i.e. they have fur on their bodies, produce live young, feed the young on milk etc.). They are also the only true flying mammals. Bats can be divided up into two main groups, the insect-eaters and the fruit-eaters with the insect-eating bats feeding on a variety of beetles, moths, mosquitos and other insects, and the fruit-eating bats feeding on ripe fruit and nectar. Bats roost by hanging upside down in trees, roofs, overhangs/verandahs or caves. The site where they roost varies according to species. Fruit bats generally roost under overhangs or caves and not in roofs. Roof-dwelling bats are almost certainly insect-eaters. Although the noise bats make is generally of a higher pitch than what humans can hear, some of their calls are audible to us, i.e. their social contact calls.

Being so highly specialized, especially in terms of feeding, and not requiring material to build a nest in the way rodents do, the gnawing sounds heard in one's roof can seldom be attributed to bats. The presence of dung is also not a good reason to accuse the bats of causing damage. Although visually similar, the faeces of the two species is very different - bat dung is crumbly and dry as a result of the insects they eat whereas rat faeces is sticky and doesn't break up easily when rubbed between the fingers.

There are many misconceptions about bats. For example, bats are not blind, they have excellent eye sight. Bats will not nibble your ears at night nor get entangled in your hair. While some bats do carry rabies, this percentage is small and you stand more chance of getting rabies from your dog than from a bat!

Bats have a crucial role to play in the ecosystem. Fruit eating bats are the natural pollinators of the sausage and baobab tree and also play a role in the pollination of commercially important plants such as mangos, figs and avocados. Insect eating bats eat a variety of insects including mosquitoes and coddling moth, a major problem in wheat farming areas. The spraying of these crops has a direct impact on the bats feeding on the insects in the area. Secondary poisoning and a decreased availability of food being the main concerns.

There is little to no protective legislation for bats in South Africa. Currently, only two species are formally protected, despite 10 species being listed as threatened with extinction in South Africa's National Red Data Book; the Short-eared Trident Bat (Cleotis percivali) and Rendall's Serotine Bat (Neoromicia rendalli) both being listed as Critically Endangered.

Despite the advantages of having bats around, they are still considered a pest species by many people, especially homeowners, as they can be noisy and their faeces and urine can stain walls and floors and create an unpleasant odour. As a result, members of the public sometimes want bats removed from their properties and may take matters into their own hands, often with disastrous results. There are no poisons registered for use against bats in South Africa. Therefore, the use of any poison, Jeyes Fluid, Chlorine or other substance, is illegal and can result in a fine or even a jail sentence. These use of these substances is also cruel and unnecessary.

Should you have bats in your roof, there are other ways to get rid of them. Firstly, establish that they are actually bats. You might have bats roosting in a tree near the house and have rats in the roof - suitable products such as Racumin can then be used. Then, if they are bats, determine where the bats are going in and out of the roof - there may be more than one hole. Seal up all but one hole. Hang a cloth (a dishcloth is suitable) over the one remaining hole. This allows the bats to fly out but not get back into the roof. (The function of the cloth can be compared to a non-return valve). Leave this up for a day or two to ensure all the bats are out and then seal the remaining hole. For thatch roofs or roofs with uneven surfaces, the expanding spray foam which hardens is convenient option to use for filling in holes. Bats are able to get into holes the size of your little finger so make sure all the holes are filled in.

Most people don't want to get rid of the bats, just to have them out the house. The use of bat houses is encouraged and these can either be purchased or built. Bat Conservation International's website (www.batcon.org) is very interesting and well worth consulting should you wish to put up a bat house. Alternatively, contact the Endangered Wildlife Trust's Bat Conservation Group for more info. The EWT's web address is: www.ewt.org.za