Forest & Bird ramp up efforts for pekapeka

The mahi is never-ending for Forest & Bird across Te Hoiere catchment as these Project partners are leading work to protect pekapeka (long-tailed bats) and restore their habitats for future generations. Two species of pekapeka (long- and short-tailed bats) are New Zealand’s only native land mammals, with the long-tailed species classified as threatened-nationally critical (just one step away from extinction). Forest & Bird are leading efforts for predator trapping and monitoring, weed clearing and native planting, as well as enhancing its longstanding pekapeka monitoring programme.

In 2010, Forest & Bird volunteers began their trapping efforts to protect this taonga species from predators at Pelorus Bridge Scenic Reserve. Today, this reserve’s large network has about 630 traps with 30 volunteers, each looking after a trapping line. By partnering with Te Hoiere Project and Jobs for Nature, Forest & Bird has expanded its efforts to protect pekapeka in neighbouring Rai Valley where these bats have been found to roost in other Department of Conservation (DOC) reserves. With the help of Ngāti Kuia, F&B has established a high-density trapping network across two reserves in Rai; and with the help of Department of Conservation, F&B has also established predator monitoring across three Rai reserves.

In November, a Predator Control Officer was hired to look after the high-density trapping network in Rai Valley—about 240 traps for one person! Rats remain the primary predator for our local pekapeka, says Dr, Daria Erastova, Te Hoiere Bat Recovery Project Manager for Forest & Bird.

“For predator control, there are two major differences between the reserves in Rai Valley and the Pelorus Bridge. Rai’s trapping network is higher density than Pelorus, and Rai reserves are isolated islands of native bush among farms. By contrast, Pelorus has neighbouring forest and bush that aren’t part of the reserve, where rats are freely coming and going,” she says.

“In Rai, our tracking card rat monitoring this year has, so far, shown zero incidence occurrence of rats, while monitoring at Pelorus is unacceptably high with rat paw prints in 30 percent of our monitoring tunnels,” she says.

While work continues on predator control, the Forest & Bird Eco Team has also ramped up efforts for habitat restoration across the Pelorus and Rai reserves, with the largest effort at Ronga Reserve in preparation for a major native planting. The Eco Team spent months prepping the site and removing invasive weeds, followed by a planting with the help of J&S Mears Contracting in winter 2024. In total, 20,400 seedlings across six hectares were planted, joining thousands of native plants that have been placed by volunteers over the past decade.

“Forest and Bird volunteers hold an annual planting at the reserve, headed by member Michel North. He’s planning to resume these volunteer plantings in 2025, with seedlings already ordered for both 2025 and 2026,” Daria says.

While predator trapping and native restoration work are happening year-round, Forest & Bird has just completed its sixth year of seasonal bat monitoring, which kicked off in December 2023. This annual work has gone high-tech over the years to now include radio transmitters, infrared technology and acoustic monitoring to understand the catchment’s pekapeka population. Over the summer, bat specialists and volunteers use the mark and recapture method to estimate how many pekapeka are present, which can be difficult because they can move to a new roost each night. Pekapeka are marked with a band and released, where they can then mix back in with the unmarked bats. When researchers sample the populations each year, they can estimate the catchment’s total population when banded pekapeka are recaptured. This monitoring, alongside the use of radio transmitters, takes place at the Pelorus Bridge, Carluke, Ronga and Brown reserves over the summer.

“The populations in Rai Valley are less understood, so we will ramp up our monitoring there next year,” Daria says. “Unfortunately, we now know enough about the populations at the Pelorus Bridge Scenic Reserve, and we know that they are in decline. While we can’t say for certain whether the decline is due to migration or predation, we are leaning towards predators because the habitat is ideal for pekapeka with mature roosting trees and plenty of food resources.”

In March 2024, bat specialists and volunteers also conducted a second round of acoustic monitoring. All up, 24 acoustic monitors were placed across the catchment from Kaituna to Rai Valley to capture pekapeka movements.

“This is when juveniles leave the roost to establish their new territories and start moving around. From November until late April, they haven’t moved much and have been very reliant on the females in the roost,” Daria said.

The work is ongoing for Forest & Bird, which has also undertaken rat and wasp poisoning at the Pelorus Bridge Scenic Reserve over the past year. Rat poisoning is expected to continue at Pelorus Bridge, as the numbers remain high.

“Winter is a good time to target rats with poison, as food is scarce,” Daria says. “We’ll also be looking at our existing trapping lines in Pelorus, to make them more accessible for volunteers, such as re-deploying traps from ridges to the valley floors where pekapeka roost in mature trees.”

For Forest & Bird’s Eco Team, the planting in Ronga is now behind them, and their focus will be on further weed control and plant aftercare in the area (the latter is with the support from J&S Mears Contracting and Marlborough District Council). F&B staff and project volunteers will address predator control and the seventh year of bat monitoring.

To prevent bat extinction, starting from the next year, Forest & Bird will concentrate on predator control and bat monitoring, with habitat restoration and plant establishment in the hands of Forest & Bird volunteers and Marlborough District Council.

For now, all eyes are on predator control.

“For our local populations of pekapeka, the main issue is rat control, and that’s where we will re-focus our efforts in the future,” Daria says.