Protecting our native birds for the future

We are proud to be funding the management of the 1,000 hectare Oparara Bird Sanctuary – an environmental offset programme involving the maintenance of 900 predator traps, annual surveys on kiwi and other indigenous birds, and input from indigenous bird and predator control experts.

An independent bird expert notes the Oparara Sanctuary now ‘bustles with birds’ in a way that few mainland forests do, making it a testament to the power of effective predator control and a joy for visitors to experience.

Forest bird abundance

Bird counts were undertaken in 2015 and 2018. The 2015 baseline counts were taken when year-round ground-based predator control started, and the 2018 counts were taken three years later.

Nine of the eighteen diurnal (non-nocturnal) native bird species have increased in abundance in the sanctuary since predator control began.

The increases in the abundance of South Island robins, bellbirds and tuis, have been spectacular. These three species are especially vocal and their song is now a noticeable feature of the sanctuary. The increases in weka, silvereye, kereru, brown creeper, and fantail have also been significant.

The bird community in the Oparara Sanctuary now rivals those on predator-free offshore islands, making Oparara one of the most intact assemblages of native birds on mainland New Zealand.

Kiwi abundance

Kiwi abundance, as measured by call counts in the first two to three hours of darkness, did not change from 2015 to 2018. Although it should be noted that these counts index the abundance of territorial adults and do not detect chicks and juveniles. Because great spotted kiwi probably take three to five years to reach maturity, any increase in population size resulting from predator control won’t be detectable until post 2020.

But the results of the 2018 survey are still encouraging. The two percent national decline in the species as a whole isn’t present in the sanctuary population – presumably because pest control operations both in and near the sanctuary have arrested it.

14 motion-sensitive cameras were established in the Oparara Sanctuary in late 2017 and these cameras are used to hopefully identify young kiwis. A population of young kiwi of around 10-15 percent of the total kiwi population would be sustainable.

This work will continue – along with the predator control work and bird counts to optimise predator control efficiency – for at least another 15 years.

“The increase in the abundance of South Island robins, bellbirds and tuis, has been spectacular.”

Image to left: Great spotted kiwi caught on a motion sensitive camera in the sanctuary.