Keep the pest police on call

Bats and owls have a significant contribution to make to controlling pests on farms. Provide them with adequate housing, and these insect and rodent eaters will offer a cost-effective, consistent pest-control service. Lindi Botha looks at best practices for building and erecting owl and bat boxes.

Owls and bats are specialised hunters. Research has consistently shown that they can make a big impact on reducing pest numbers on farms.

A pair of barn owls and their chicks feed on 2 000 to 6 000 rodents a year, according to research conducted by the Ministry of Agriculture in Israel.

Israel initiated a project to monitor the efficacy of barn owls for rodent control in crops in 1983 already, and following the success, increased owl boxes across the country to nearly 4 000 boxes today.

Many grain farmers there have shifted to using barn owls, and have reduced the use of pesticides or refrained from using them altogether, without an evident impact on yield. A research project looking at the impact of bats on insect damage caused to macadamia nuts in Levubu, Limpopo, found that damage caused by macadamia-nut borer and false codling moth could be reduced by 35% if sufficient numbers of bats and owls were present in the orchards. Removing the winged creatures from the orchards, on the other hand, resulted in a 60% reduction in yield.

Jordan-Michael Hardey, the communications manager at EcoSolutions, refers to bats as the ‘bug police’. “They fly around, catching insects using a process called echolocation to find their insect meals. They make high-pitched sounds that bounce off objects and return to the bat as echoes. Bats in flight can distinguish the difference in sound between a tree, your head and an insect, which is how they locate their food in the dark.”

About 70% of all bats eat insects, with each eating half their weight in insects a night. Bats are also responsible for pollinating fruit like avocados, bananas, dates, figs, mangoes and peaches, and they spread seeds.