Volunteer Steve Detlaff has developed a novel method of trapping mice and rats. The whole new concept for the Trust is thinking about the trapping of ship rats up in the trees rather than just on the ground. His reports for March and April:
Coronation Tree Trap Trial:
In early 2026 after discussions between Pukenui rangers, NRC and Steve Detlaff, it was decided to conduct a 12 month, two trap trial for rat reduction in the Coronation Reserve and surrounding areas. NRC and Tiakina agreed to supply 100 trap boxes and victor traps for the trial. These traps are counted in the trees at about head height so our trappers can access them with relative ease.
Victor trap in the tree.
Photo credit: Andy Avery
The most prolific species of rats in the Pukenui forest are Norway and Ship rats. Norway rats prefer to scurry around on the ground and ship rats spend alot of time in trees.
Initially 49 traps were supplied and deployed gradually in February. A further 11 D-Rat traps were deployed on 5th March.
Results:
Note we were hoping for a 30% or better strike rate.
February:
Strikes = 28 (57% for the month).
A rat strike comparison for the month of March with other lines in the forest:
X line (tree traps):
| X line (tree traps) | 28 |
| Buffer line | 26 |
| Violet line | 18 |
| Coronation line | 14 |
| Aqua line | 13 |
| Holman line | 12 |
| Red line | 11 |
| All the rest of the lines have under 10 each |
The combined strikes since the first trap was deployed is 36, giving us a massive 73% strike rate. This is indeed an amazing start to our 12 month trial, but early days yet. After just over 3 weeks the 11 D-Rat traps disappointingly at this stage and are yet to get a strike at all. We look forward to getting and deploying the remaining 40 traps for even better results in future months.
April Results:
Feb strikes = 8, March strikes = 28 (57% for the month), April strikes = 27 (55% for the month)
A predator strike comparison for the month of April with other lines in the forest:
| Buffer line (border around the forest) | 55 |
| X line (tree traps) | 27 |
| Green line (around Whau dam) | 22 |
| Whero line | 15 |
| All the rest of the lines have under 10 each |
The 11 D-Rat traps disappointingly have yet to strike. They have recently been moved to a location around Whau Valley Dam to see if they will start catching rats there.