"They reset themselves 100 times, and also rebait themselves every night. The trigger mechanism is an infrared beam, so the pest doesn't even need to touch anything, lessening the chance of trap shyness."
The trap pictured had caught 17 possums, two rats and a mouse in seven nights. Three months on it had despatched more than 40 possums.
The traps would be on a 75m x 75m grid, ensuring one would be within every rat and possum's territory.
"The other great thing is our volunteers no longer need to scrape out maggoty rats, where there is a real threat of catching leptospirosis. Checking the trap lines becomes enjoyable," the spokesman added, "but the real winners in all this is our amazing native wildlife.
"We still need a further 287 traps to complete the project, but this is a fantastic start. If you are keen to sponsor a trap, please visit our website (www.baybushaction.org.nz) for details."