Firstly it must be said that there is no problem living with bats in your roof – people and bats throughout the world have cohabited for millennia. There are no known health hazards associated with bats in roofs and bats do not have parasites that can transmit diseases to humans.

However if bats are entering living quarters through chimneys and broken air vents then they should be prevented from doing so by covering the holes with a mesh of a gauge of 4 mm or less. In South Africa, bats roost in roofs and if undisturbed are typically present throughout the year. However, bats may be present just for a particular season. For example, a maternity colony where females produce and rear their young may only be present in summer (breeding months).

The maternity colonies of bats are often vital to the local survival of a particular species. If that species has only one or two roosts suitable for breeding within a large area then the species is extremely vulnerable if there is any disturbance or destruction of a roost.

Bachelor males may use several roosts on a transient basis as they attempt to establish their harem. Successful breeding males of some species may never roost together with the females except for a brief period of mating.

The majority of bats do not abandon their roosts when disturbed, although when roosts of Large-eared Giant Mastiff bats are disturbed, the bats abandon the roost and temporarily occupy several alternative roosts in the general area.

Colony sizes of roof-dwelling South African bats generally vary from just a single male to over 500 bats in the case of some free-tailed bat species. However, bats are slow breeders and householders need to understand that bats do not “breed like flies”, nor will their colony size keep on growing beyond a certain stable size.

Quite often householders only notice bats in their roof during the breeding season when mothers and young become more vocal. This does not mean the bats are not present throughout the year. Bats occupy all sorts of buildings, including both cavity and solid-walled and roof structures varying from corrugated iron through tiles to thatch. Because of their different temperature needs different species may prefer different kinds of roofs.

For example, Angolan free-tailed bats in the Lowveld are adapted to roosting under hot corrugated iron roofs; on the other hand, bats that readily go into torpor, like the Yellow House bat, may prefer colder roosting sites.

Bats often emerge from roofs at dusk erratically and unpredictably, or in bursts, presumably to confound potential predators. Roof-dwelling free-tailed and vesper bats are capable of landing and crawling, and using very narrow roost entrances, while horseshoe, leaf-nosed and slit-faced bats are all incapable of crawling, and when occupying either roof or basement spaces (which occurs only rarely as these are typically cave-roosting species) require a substantial opening to fly through and then hang up on a suitable perch.

There are several human activities that may impact bat colonies in roofs and lead to disturbance, evacuation, or even to bats becoming trapped and dying of starvation. In cases of renovation, re-roofing, demolition, timber, or pesticide treatment, when bats are present householders should seek the advice of an expert to minimize disturbance of the bats. Possible mitigation measures may include erecting bat houses and evicting the bats or timing the work to avoid the breeding season when flightless young could be trapped.

Are there bats in the roof?  The first step is to find out whether bats are present.

Frequently householders hear noises in the roof and believe they have bats. Often these noises turn out to be caused by rats or birds. Bats may have been seen flying around outside the house and it is assumed they came from the roof. In other cases, a previously known bat colony may have moved away or even been inadvertently poisoned.

To confirm whether bats are present in a roof, follow this simple procedure: Check for the presence of bats by listening for their chittering noises in the roof.

• Shining a torch on areas where bats are likely to be hiding may help to elicit a response; note that some of the smaller bats hide in crevices and will not be seen during the day.
• Always look out for tell-tale piles of scattered bat guano (droppings). Bat droppings are irregularly-shaped and not pointed at each end like a rodent dropping; they do not have the white uric acid tips characteristics of gecko or bird droppings. They also crumble easily into fine chitinous insect parts. As a rule, bat colonies in roofs are localized in one area, although bats roosting between the tiles and roof lining may sometimes be more widespread. In most cases, bats seem to roost close to where they emerge and enter the roof, but some colonies will crawl some distance between their preferred roost site, and the point of emergence.
• The first and favourite place to look for a bat colony is on the gable apex wall, often tucked up between the brick wall and rafters. Piles of droppings at the base of the gable apex are usually the first sign of such a colony.
• Other common roost sites are above the eaves, on top of the ridge beam and other rafters, underneath the ridge tile, between tiles, and in broken air vents.

Fruit bats messing on walls are often a problem. This frequently occurs when bats are feeding on a nearby tree. It appears that the most effective way of preventing this is to illuminate the wall by shining a light onto it. This allows the bats to see the wall in good time and avoid it.

Yellow paint seems to be harder for the bats to see, white paint should be used in areas of high fruit bat passage. Painting the walls with a smooth high-quality paint (such as Plascon Velvaglo) can help as splats can be easily washed off, providing that this is done first thing in the morning before bacterial decomposition of the faeces causes a stain.

Complaints are often received from homeowners about fruit bats calling outside their bedroom windows at night. The calls are either the bats squabbling with each other or the males calling to advertise their territory and attract females.

The male’s call is a resonant “pinging” sound. Although loud, calling fruit bats are indicative of a healthy environment and part of the night sound of Africa. If the ruckus of the bats is feeding on a fruiting tree in the garden, then the disturbance will probably last just a few weeks until the fruit is all consumed.

Trimming the branches closest to the windows will move the bats further away. We do not recommend cutting down trees, especially since many indigenous trees are now protected and may only be felled if a permit is granted by the local authority. Cutting down trees decreases the natural habitat available to all species of wildlife.

“White noise” will counteract bats’ calls. This can be produced by playing a radio off-station to produce a “hiss”, by running an air conditioner or an electric fan.

If all else fails, try using earplugs! Never hose fruit bats out of a roost. Their wings are fragile and the force of water from a hosepipe is sufficient to seriously injure them.

Exclusion is the process by which bats are removed from buildings, using a humane, non-lethal method, at those times during the year when there is no young present.

Simply put, the exclusion is the blocking up of the bats’ access points after they have left the roofs during the evening to hunt for food.

While it is preferable to simply allow the bats to remain in the roof spaces, some circumstances could make exclusion necessary.

These are:

• If poisoning or fumigation of the roof is to take place to eliminate wood borer or other insects;
• Renovation or reconstruction of roofs which could result in the injury or death of bats, or the closing of their exit points;
• If a very large colony of bats has caused problems like excessive noise, smell, or sagging ceilings due to the accumulation of guano, other methods of minimizing these problems have had limited success.

Exclusion is difficult and time-consuming and best done by experts, although this is expensive.

EXCLUSION MUST NEVER BE DONE IN THE SUMMER MONTHS WHEN BABY BATS ARE PRESENT.

In Europe legislation specifically gives protection to all bats, their roosts, and their habitats, with severe penalties for interfering with bats.

In South Africa, only Otomops martiensseni enjoys such specific national legislation under the National Biodiversity Act, but all other bats are protected under more general national legislation such as the prohibition of cruelty to animals, and the prohibition of the use of non-registered poisons.

Bats are also protected by provincial legislation. Provincial Nature Conservation Ordinances provide for the protection of plants and animals through various levels of protection and schedules which differ between provinces.

For example, in KwaZulu-Natal, two species of bats, the Large-eared Giant Mastiff bat (Otomops martiensseni) and the short-eared trident bat (Cloeotis Percival) are listed under the highest priority ‘Specially Protected’ category, along with species such as the black rhino!

Several other bat species are listed under the ‘Protected’ category, where they are afforded legal protection against human disturbance.

It is illegal to kill bats, except to euthanase a sick or injured bat by an approved humane method.

It is illegal to use any poison or chemical to kill bats.

It is illegal to shoot bats.