New Zealand researches bat behaviour on Southern Links road project
Thermal imagery, acoustic monitoring, expeditions in the dead of night and a bat named Kathy might sound like a sci-fi storyline, but it’s all happening south of Hamilton.
The NZ Transport Agency and Hamilton City Council have been conducting environmental research into bat behaviour as part of the Southern Links road transport project south of the city, and the data is providing exciting information for scientists and bat enthusiasts.
Hamilton City Council’s Nathanael Savage says the research is still in its early days but is already adding new information to what was previously thought about bat habitats and flight patterns for the long-tailed bat (pekapeka-tou-roa), one of the two surviving native bat species in New Zealand.
Among the findings has been the confirmation that bats are roosting in man-made roosting boxes – referred to as ‘Bat houses’. This is first time detailed recordings have been made of groups of bats using the artificial houses in Hamilton. Tracking has also shown extensive bat flight paths, including across open countryside, although Nathanael notes that the research is not yet complete.
“The research team captured a number of bats and placed transmitting devices on a small sample of them. The tiny radio transmitters only last a few weeks before they fall off the bats, but we’ve been able to follow the movements and record them,” Nathanael says.
“Over the course of two weeks one female bat, nick-named Kathy (after the original Batwoman Katherine Kane), seemed to travel extensively to forage and roost. Our team were able to follow her further between various roosting sites and on multiple nights found not just Kathy, but several other bats roosting in a ‘bat-house,’ one of dozens of man-made nests placed around the city.”
The bat houses have been made and sponsored by local schools, scout groups and volunteers, since 2011. The initial project was the brainchild of a University of Waikato student Darren Le Roux while undertaking his masters study and promoting bats within the city. The concept initially was that bats one day might roost in the artificial houses and at the time he thought it could be years, if ever at all, before this happened.
The houses are made from untreated wood, with a mix of design versions adapted from overseas experience with similar bat species. The houses have either single or multiple chambers, and are situated in areas to maximise the potential roosting habitats characteristics of both female and male long tailed bats.
The tracking and monitoring programme was undertaken by specialist bat ecologists engaged by Hamilton City Council and NZ Transport Agency as part of environmental investigative work underway for the Southern Links roading project. The Department of Conservation was engaged with on this work and contributed extra funding to extend the tracking programme to increase the amount of data gathered.
“Long-tailed bats are an important part of the ecology of Hamilton and it’s great to see that through this project we’re getting a better understanding of them,” says Transport Agency Project Manager Barry Dowsett.
Looking out for the city’s bats is not a new thing for Hamilton. Project Echo is an advocacy group established with support of the Council, Waikato Regional Council, and the Riverlea Environmental Society Inc. As a volunteer group they conduct their own education and monitoring programmes aimed at monitoring the state and advocating for the welfare of, the bat population.
Project Echo spokesperson Anna Casey-Cox says the results of the research are adding to what is known about bat populations in and around Hamilton and was a great boost for the project.
“I’m told when Darren found out the bats had arrived, he was ecstatic, as were all involved in the project. It’s been a number of years with regular checking in the hope, with disappointment each time. We did get pretty excited once only to find that a large spider had taken up residency! The discovery is great news for all involved!,” she says.
“Hamilton is one of the only cities in New Zealand still supporting a resident population of long-tailed bats and because they tend to roost during the day and live in holes in old and dead trees, there’s a lot more of them than many people realise,” Anna says.
“This research is great news for our team and adds something new to what is known of the behaviour of these unique mammals. The next trapping and tracking programme will happen in March and we are delighted to see Council and the NZ Transport Agency working together and with others to better understand our bat population. We’re looking forward to seeing the findings of this work.”
Nathanael says the new data will raise the profile of Hamilton’s bat population, but adds a note of caution: “We’re quite excited to be gathering such great information and seeing bats so close to the city. However, we all need to remember the bats are a protected threatened species. We use expert bat ecologists to do all our work which requires specific permits under the Wildlife Act,” he says.
“If anyone is interested in learning more about bats and perhaps becoming involved they should do this in a responsible way such as through the Project Echo group and existing education programmes such as the popular Bat tours run out of the Waikato Museum.”