He says the main reward is seeing the North Island robin and tomtits return to the bush.
"The birdlife up the Hinemaiaia is phenomenal."
He says modestly that trapping 1000 rats is not that big an achievement.
"People like David Bedford trap that many vermin a month and plenty of others have trapped many times more than I will. It's also taken longer than I expected because of doing weed control, picking up rubbish etc."
In the past eight weeks Didymo Dave has cleared away Japanese honeysuckle, broom, blackberry and gorse. His next goal is to turn areas in the upper Hinemaiaia back into recreational areas he calls "parks".
Plenty of visitors have come to see how he's getting on at the Hinemaiaia and Didymo Dave says he wants to thank everyone who came along.
"Thanks to everyone who brought me gluten-free biccies, anti-inflammatory cream for my tweaked Achilles and who helped me drink heaps of coffee while solving the problems of the world."
His humorous posts on Facebook have drawn people into conservation, and Didymo Dave says he will supply traps to anyone who will use them.
"Other people contribute in different ways. One person paid $200 for a resettable trap."
A year ago Lesley Hosking and Chris Pritt took over the running of the trap line Didymo Dave established between the Hinemaiaia's first and third carparks.
"They said, we'll do this so you can go and do something else. They are doing a fantastic job." He encourages anyone to get in touch as he is keen to share his knowledge and encourage conservation efforts. Find him on Facebook @DidymoDave or contact him on 027 240 9603.