By Alan Hewett, Chiltern
When we first moved onto out rural property we were plagued by Sparrows. They nested in the roof, were noisy, messy and hostile to the native birds. We tried various measures to get rid of them, including building a Sparrow trap which caught nary a one. Then, over a period of time they completely disappeared. What had happened? The answer came when we saw a Yellow –footed Antechinus drinking from a birdbath. Often mistaken for a rat they are a marsupial mouse and they are a predator. They had feasted on Sparrow’s eggs and probably nestlings. Since then we have had no introduced birds in our garden. Of course Antechinus don’t discriminate, and they have predated on the Wrens that live permanently in our garden.
We had a similar experience when we discovered a Gould’s (Sand) Goanna that had nested in a burrow in a fire pit. It would come out and sun its self and became used to us walking by, even allowing some close up photographs. Soon though it began to cruise around the garden looking for victims: birds and their eggs, small mammals and lizards. It was hard not to interfere and chase the intruder away, but they are wide ranging and soon moved on.
Species survive by predating on others. Raptors fall into this category. They keep mice and rabbit numbers down. Birds such as Ravens, Kookaburras and Currawongs will often eat small birds and nestlings.
But what happens when a native species population gets out of control? We have experienced a kangaroo explosion in numbers in recent years. Some covenanted properties have tried constructing bigger fences to keep kangaroos out, but this is expensive and forces the problem onto neighbours. We have applied for a permit to cull but there are restrictions. A more powerful rifle has to be used; carcasses cannot be taken off the property because of bio- security reasons so have to be buried.
We have created the conditions for kangaroos to flourish. Ample feed and water means they breed at a rapid rate. They are not selective grazers either and orchids, wild flowers and ground cover suffer.
Culling presents an ethical dilemma for landowners who are dedicated to protecting their native flora and fauna, but is it so different from predation?