The Threat to Wildlife
Wire Mesh Canopies are Inadequate
Wire mesh canopies with rabbit-sized entrances to cover poison baits are sometimes used to restrict access to the baits. However the effectiveness of such canopies is limited. Firstly, wallabies and kangaroos can simply knock them over or lift them up to gain access to the poisoned carrots. The NRA review recommended "fencing to exclude larger species such as macropods”. But few landholders are likely to build such fortifications to keep non-target animals away from the bait. The canopies used by local councils and government authorities are simply a V-shaped mesh cover with open-ends half-heartedly held down by tent pegs (see photo).
Regardless of how strongly fixed the canopies might be, small native animals will be able to access the bait as easily as the rabbits do. It is for this reason that the pindone label forbids users to "lay bait trails in the vicinity of kangaroo, bandicoot and native rodent refuge areas". Yet thethe Local Land Services (LLS), formerly the Livestock Health and Pest Authorities (LHPA), has promoted pindone use in areas that include native animal habitat harbouring small mammals and assuring local residents and council officers that native wildlife are not at risk.
Even if the canopies are properly constructed, routinely used and securely fastened to the ground, possums will still get access to carrot baits. We have been conducting experiments to test which animals will eat carrots and which will gain access to carrots covered in a heavy wire mesh cage with a restricted entrance. We have found that wallabies and possums will readily eat carrots and both possums and swamp wallabies will squeeze through a confined entrance, forcing back the mesh, to get at carrots. Possum mothers carrying young on their backs also allow the infants to dismount and forage independently. Some of these observations are shown on the video below.
At best the canopies only defend against primary poisoning of larger wildlife. They cannot prevent secondary poisoning. If pindone baiting is successful there will be dead and dying rabbits around for predators and scavengers to feed on.
A Thai translation of this page can be found at http://eduindexcode.com/the-threat-to-wildlife-2/