Problems with Bats
THE BAT INTEREST GROUP
OF KWA ZULU NATAL
Copyright Paul Buchel
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.
, bat 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).
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 own harem. Successful breeding males of some species may never roost together with the females except for a brief period for mating. The majority of bats do not abandon their roosts when disturbed, although when roosts of Large-eared Free-tailed 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 a number of human activities which may impact on 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 in order 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.
BATS IN ROOFS
For comprehensive information on this subject we recommend the Bats KZN publication Bats in Roofs.
for R75 incl. p&p.
Copyright (C) 2015 Bat Interest Group of KwaZulu Natal All Rights Reserved
082 445 0585
Living With Bats
Bats of KZN