Our secret allies
Bats are fast and agile animals. They have an insatiable hunger for insects, and can consume hundreds of bugs in a single night. Doesn’t that sound like something that most people would appreciate? Surprisingly, they are often feared, hated and even eradicated. Perhaps it’s the unknown and secret world of these amazing animals that makes people uneasy; this lack of knowledge perpetuates imaginative myths and negative perceptions.

The majority of bat species prey on insects. The effect of insect pests on crops is a major problem in agriculture. An estimated 13 per cent of the potential world crop yield is annually lost to pests, with insects being the main culprits⁹. De Hoop Guano Cave in the Cape Province of South Africa is home to the largest aggregation of bats in South Africa, with a calculated 300 000 bats roosting there⁶. This colony consumes an estimated 100 tons of insects annually, making an invaluable contribution to the pest control on farms in the Bredasdorp area^{3, 7}. Similar examples are found in other parts of the world, like that of the Brazilian free-tailed bat that preys on Corn earworm moths (Helicoverpa zea). A single Little brown bat (Myotis lucifugus) is able to consume 500 insects in less than an hour¹.

Bat houses
Bat houses are a cost-effective initiative that increases the prevalence of bats on your property, and thereby decreases the number of insects in your area. Urban residents, lodge or recreational venue owners, and farmers, can all benefit greatly from having inhabited bat houses on their properties. It is a cheaper and environmentally friendlier way of helping to keep insect populations under control as opposed to the continual use of poisonous chemicals that, apart from being illegal, do not provide an effective long-term solution. If bats that have been living in your house roof are poisoned and die, new bats will simply take their place. It is preferable rather to bat-proof the roof and provide alternative housing for the bats.

EcoSolutions have a wealth of knowledge in the supplying and installation of bat houses, and are committed to the continuous improvement of the success and cost-effectiveness of these bat houses. Furthermore, EcoSolutions can also deal with bat problems in roofs of houses and buildings by excluding the bats and then offering them an alternative home in the form of a bat house.
In addition, nature lovers might enjoy the spectacle of watching bats emerge from a bat house, swooping around them to catch insects with unmatched agility.

Why empty?
There are many reasons why bats may choose not to live in a bat house. They are wild animals and, like all wildlife, cannot be totally controlled by humans, or forced to move into a bat house. Current research is increasing our knowledge of the factors that determine whether a bat chooses to live in a roost or not.

If your bat house is empty it may be because:

• The bats in the area reside in a nearby safe roost and may decide not to leave their home unless they are excluded from a house roof, for example.
• The bat house is being disturbed too much, e.g. shining a flashlight into the house every day or during the night to see if bats have moved in. The house should not be checked more than once a fortnight.
• The bat house is not getting enough sunlight. Shrubs and bushes around the bat house may have grown to such an extent that they prevent sunlight from warming up the bat house. Building a new lapa or other structure in front of the bat house can also block the sunlight, so observe the position of the sun carefully and consider it for all seasons before installing the bat house.
• Insecticides in the garden or on crops that are poisonous to mammals when taken orally, may mean the bats have either died from eating insects contaminated by the chemical or they may have moved to safer grounds. Refrain from using obnoxious insecticides; this will benefit the entire environment.
• The food source for the bats has decreased. This may happen when insects decline during winter, which is natural, or when large spaces of grassland or bushes have been cleared around the bat house. In both cases the bats will probably return when their food source returns.
• Your bat house is too wet or cold inside. This may happen if the bat house is not maintained and rainwater leaks in or cold draughts blow through the house. Bats like warm, dry roosts and will move to such a place if their home is too cold and wet. EcoSolutions offers a standard maintenance service with their bat houses.

Our bats
The Order of bats, called Chiroptera by scientists, is the most diverse group of mammals in the world second only to the Order Rodentia (rodents). There are over 1100 species of bats, which occur in all parts of the world except for the most extreme desert and polar regions. There are 74 bat species known in Southern Africa, of which 56 species occur in South Africa and 39 in the northern part of South Africa, which comprises Gauteng, Limpopo, Mpumalanga and part of Northwest Province¹⁰. The Chiroptera is subdivided into the larger fruit-eating bats that belong to the Suborder Megachiroptera and the smaller predominantly insect-eating Suborder Microchiroptera¹⁰.

Figure 1: The general anatomy of a bat. Image from Taylor (2000).

Figure 2: The body parts that may be measured by scientists when identifying bats. Image from Taylor (2000).

South African bats may live in a variety of different places and the choice of roost usually differs with the species. These different roosts can include caves, cracks and crevices in rocks, under loose bark, under overhanging leaves, inside road culverts or hollow tree trunks (especially baobab trees), aardvark burrows, in basements and as many people already know, inside roofs. Only bats associated with human structures or gardens are discussed here. Almost all our insect-eating bats forage at night and seem to be opportunistic in their choice of food, limited only by the size and/or hardness of the bug.

Table 1: The most common South African bat species usually associated with human residences and manmade structures, with less common species shaded red.

Author of About bats: Werner C. Marais (2009)