Possums
Why are possums pests?
The Australia brush-tailed possums is considered to be major ecological and agricultural pest throughout New Zealand. Possums feed on a variety of native and introduced vegetation. By continually browsing on certain trees possums can eventually kill the trees thus altering the structure of the forests so that they are less suitable as a native wildlife habitat. Possums strip fruit from orchard trees, damage shelter belts and feed on crops, flower and vegetable gardens.
How do you know the culprit is a possum?
Before implementing any control methods correct identification of the pest responsible for the damage is necessary. Possum browsing is distinctive:
- Possum are untidy eaters and the ground will be littered with half eaten leaves, flowers, or fruit.
- The stalk and midrib are left in broadleaf species
- Small branches may be broken near the top of the tree.
- When moving from one area to another possums may leave track marks, particularly through grass.
- Claw marks on trees and fence posts may be visible.
- Possum droppings are 2.5cm long, thicker than a pencil and covered in a slimy film when fresh.
- Possums are highly territorial and fights may be heard or fur left behind.
How to deal with a possum problem
Trapping
The Timms Trap
Timms traps kill possums quickly using a spring loaded metal mouth which snaps down on the neck of the animal breaking the neck or windpipe resulting in a rapid death. Timms traps need to be baited with fresh fruit such as an apple, orange or carrot to entice the possum to stick its head through the key hole. Teach pets to avoid the trap by setting it then dropping it near them. The loud bang will frighten them and encourage them to avoid the trap in future.
The Live Capture Trap
Live capture traps are cages which catch the possum when it reaches for the bait on the trigger arm releasing the trip pin and closing the door. Possums are caught live and need to be disposed of humanely. To remove a possum from the trap coax the animal towards the back, grab its tail and pull it out. Allow the front paws to maintain contact with the ground to prevent it from climbing on you and to distract it for you to deliver a sharp blow between and slightly forward of the ears using a heavy stick or hammer to stun the animal so that it can be placed over a rock or solid tree root where a hard blow to the same place will kill it. These traps are mainly used in areas where the chance of catching domestic animals is high. Traps should be sited near to the plants under attack. Set the trap by attaching a piece of fruit to the trigger arm and lifting the door and holding it open with the trip pin.
The Leg-hold Trap
The Victor No. 1 coil spring trap is a widely recommended leg-hold trap featuring non-serrated jaws with spring tension sufficient to hold a possum without causing major injury. These traps are small with a light structure for easy carrying. Leg-hold traps do not require the possum to enter a cage or box or eat anything. They catch possums behaving naturally. Leg-hold traps should be placed where possums will encounter them during normal movements such as at the bottom of a tree displaying obvious possum sign or a possum track. When setting traps ensure that they are steady and level with the 'dog' orientated to the tree and set at a hand width from the tree base. Where there is a risk of catching other animals traps can be raised or shielded with rocks or sticks. With raised traps the chain needs to be long enough for the trapped animal to fall to the ground.
Lures should not be required with well placed traps but if lures are used these should be applied to the base of the tree and NOT in the trap itself. Trap lines in forested areas are normally set at 20-40m intervals. Traps need to be checked every morning.
Caught possums should be treated with caution as they can inflict injury with claws and teeth. Grab the possum by the tail and pull it out the length of the chain. Deliver a sharp blow between and slightly forward of the ears using a heavy stick or hammer to stun the animal so that it can be placed over a rock or solid tree root where a hard blow to the same place will kill it. Non-target species such as a cat or bird should be covered with a coat or blanket and carefully released. If injured the animal should be taken to a vet for treatment.
For more information
Contact a Bay of Plenty Regional Council pest animal officer.