One of the biggest pests in our orchard were rats and mice, and we've had our fair share of them. They have eaten planted seeds in the nursery, chewed young trees off, eaten holes in pots and water lines, and just before fruit are ripe enough to pick, they seem to delight in nipping quite a few before they pick the one they decide to make a meal of. I have been heard to say they're jolly little pests.
We've trapped a lot in live traps. We don't like using ordinary rat traps that kill, because other non-target birds, reptiles and little animals are sometimes killed, even sometimes, the predators of the rodents. Poison is out altogether at our place for rats as we are trying to build up the predator population, and obviously the predators eat dead or dying rats, so we would be defeating our purpose by killing off the rat-eaters too.
Domestic and feral cats (that is domestic cats gone wild) are shot on sight. We don't have dogs, so we do have a good cross-section of native birds, reptiles - being snakes all kinds and large skinks, and native cats, 'Quolls', that are all good rodent-eaters. We have seen the swamp pheasants which are very good ratters pinching the young rats from nests in the grass. Most large ground birds will eat rodents if they get the chance. Ibis, all Cranes, Curlews, Herons, Scrub turkeys also polish off mice. Kookaburras and hawks are sure killers.
By accident, we found out how to help one of our best predators - the owl (because it's a night hunter) to increase its catch. Now and again when I was a bit too slack to bury our household scraps, I just dumped them on the open ground near a fruit tree for compost (well, that was my excuse). Using the same tree for about a week which was well out in the open and surrounded by short mown grass, suddenly, bits of rats, tails, legs and white tail rat parts could be found around the yard. We had noticed at night a long sharp whistling sound that we hadn't heard before. "Owls," our bird photographer neighbour told us. The scraps were bringing the rats and mice out into the open at night to feed and the owls had learnt to sweat on the same spot each night for a feed too. After the owls had cleaned out the rats in one spot, we helped them by dumping the scraps in a new spot and bringing more rodents into the open.
I'm not sure what type of owl we have helping us, but a quick look through the bird book shows we are lucky to have quite a lot of owls in our area. The Rufous owl, the Boobook owl, the Barn owl, the Barking owl, the Masked owl, the Sooty owl, the grass owl. The Papuan Frogmouth owl and Rufous owl also dine on flying foxes. There are more owls around than people are aware of, because owls are nocturnal and stay well-hidden and asleep during the day time. We are just not aware of the help owls give us.
The biggest threat to the owls is land clearing and fires. The falling of old trees with holes in them, which owls use for nesting and camping, result in the destruction of whole families which have been in the area for decades. Fires are murder to owls. Besides smoke suffocating the helpless young in nests, the fires usually burn down the older trees with holes in them on a large scale, depriving any surviving adult bird from any chance of re-establishing in the same area.
Fires have brought the grass owl (the one that nests and lives mainly in long grass and reeds) to near extinction. The fires are usually lit "to get rid of the rats," which they never do. The fires just do the opposite and wipe out the rats' enemies.
Another advantage is, while we've got the owls working on our rats, I've got an excuse for not having to bury the scraps. We still set some live traps. Any fauna we catch other than rats are let free, and the rodents, after killing, are left to help bring in more predators.
It's quite nice to wake at night and hear the long shrill whistling of an owl and know our native owls are working for us. With a bit of consideration, we all could have more owls, less rodents and more abundant fruit and healthy life.
DATE: September 1986
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