Coronation tree trap trial
Pukenui Trust, Tia Kina, NRC
There has been a lot happening in May.
In addition to the 49 original victor traps, there was another 21 and then a further 30 supplied totalling 100 all up. There are still 19 traps to be deployed into the bush. The 10 D-Rat traps have finally started catching with 5 rat strikes recorded after being moved to Whau Valley dam general area.
NB: As we have been deploying traps throughout May, the percentage is hard to calculate accurately due to numbers in the field constantly changing. May’s figures are based on 70 Victor, 10 D-Rat, and 10 Waiarohia Stream Victor traps. All 100 Victor tree traps should be in the field by the end of June.
I have for some time been concerned that rats from the Waiarohia Stream (Western Hills Drive) will cross the road and repopulate the Pukenui forest, therefore I have expanded the trial to include 10 Tree traps I have installed along the stream from Manse St to Rust Ave. These traps although included in trial numbers are installed under the Tia Kina project not the Pukenui forrest one.
Observations
Bush rats seem resistant to D-Rat traps and it is believed this may be due to their plastic construction. Perhaps city rats who are used to plastic may be more trusting. We are looking at covering the traps with dirt or clay etc to reduce this resistance.
We have found washing the wooden boxes that hold the Victor traps in dirty water seems to lessen rats resistance to new traps. Ironic to wash something to make it dirty.
Rats seem to love milo.
RESULTS. (Includes mice as well as rats)
February Strikes = 8
March Strikes = 28 (57% for the month)
April Strikes = 27 (55% for the month)
May:
70 Victor traps = 54
10 D-Rat traps = 5
80 TOTAL (Pukenui) = 59 (73% for the month)
10 Waiarohia Stream = 11 (110% for the month)
GRAND TOTAL = 70 (77% for the month)
TOTAL STRIKES = 133 (Predators caught since trial began in February).
COMPARISON
A Predator strike comparison for the month of May with other lines in the forrest presented below
X Line catches (tree traps) = 59
Buffer Line (Border around the forrest) = 42
Whero Line = 15
AT line = 13
Green Line (Around Whau dam) = 12
Orange Line = 10
All the rest of the lines have under 10 each
Steve Detlaff 2/6/2026