Chew cards measure Miramar’s predator-free efforts
March 28, 2019
Chew cards collected on Saturday will reveal the effect of predator free groups in Miramar.
Collection volunteers reported noticing less bite marks than last year but only the official results will tell.
This data collection exercise was part of a Wellington-wide project by Predator Free Wellington, a partnership between Greater Wellington Regional andWellington City Council, the NEXT Foundation, and local iwi.
Forty-four Wellington suburbs are involved in a project to become New Zealand’s first predator free city and restore native birds and plants to the area.
Small squares of corflute (a type of plastic often used for real-estate signs) were injected with peanut butter to attract animals and placed in a 200msq grid on the Miramar peninsula.
About 20 volunteers placed the chew cards around the peninsula, some on foot or on bikes, some with backgrounds in orienteering for the harder to reach locations.
The cards stayed out for three nights,and volunteers collected them for analysis on Saturday.
Analysis will involve looking closely at the size and shape of the bite marks in the cards to predict the type and quantity of animals living nearby.
Team leader of environmental science for the regional council Dr Philippa Crisp said chew cards were used as a way of gauging the density of predators in Miramar for the last two years.
Last year’s results showed a 5 per cent increase in rats despite increased trapping efforts.
However, Crisp said the season had been particularly good for rat breeding, with mild weather and abundant food supplies, so the small increase was to be expected.
Chew cards were small, and did not account for the animals that might walk past without biting them. They also worked less effectively in the rain.
Crisp said chew cards were easier for use in residential areas as they were smaller and less obtrusive than other methods and were suitable for the “snapshot” they wanted to get of the area.
She predicted they could have the official results back in under three weeks.