The Forest Bridge Trust – Long-tailed bats in Rodney

For the past few months, The Forest Bridge Trust’s ecologist and biodiversity advisor Virginia Moreno has been putting bat detectors up across the rohe and is happy to report that the long-tailed wattled bat, or pekapeka-tou-roa, a nationally critical species, has been detected in the Rodney area. One of our most intriguing residents, long-tailed bats (Chalinolobus tuberculatus) are endemic to Aotearoa.

These remarkable mammals have evolved in isolation for millions of years, resulting in unique characteristics that distinguish them from other bats around the world. As their name implies, they have elongated tails that can be as long as their bodies, yet they are only the size of an AA battery, weighing between eight and 14 grams and with the wingspan of a hand. Long-tailed bats are active at dusk and into the night, playing an essential role in pest control, pollinating plants and dispersing seeds including kiekie, dactylanthus and pōhutukawa. Bats can also greatly reduce the population of mosquitoes – it is claimed that a single bat can consume around 1000 mosquito-sized insects a night.

With impressive aerial agility, long-tailed bars can fly at 60kmph navigating by producing ultrasonic sounds. It has been through their high frequency echo-location calls that we have been able to detect and monitor them with electronic bat recorders. Long-tailed bat’s echo-location calls include a relatively low frequency component, which can be heard by some people, though most calls are at a frequency of 40kHz which is higher than the human ear can detect. We have detected long-tails on Govan Wilson Road and are confident that there is a sizeable population in Rata Bush. This is positive news as pekapeka-tou-roa is on the nationally critical list (most severely threatened, facing an immediate high risk of extinction).

Long-tails like to roost and raise their young in the cavities of older trees, making them easy prey. Predation by introduced mammalian predators such as mustelids (stoats and weasels), as well as rats and possums, have had a devastating impact on their numbers since the early 20th century. During winter, bats go into a state of torpor, taking very long naps of up to 10 days to conserve energy. With a drop in temperature and food scarcity, their winter activity is estimated to be only five per cent of their summer activity. This is when they are at their most vulnerable. Ship rats and stoats are also working hard to survive the winter. Ship rats use their acute sense of smell and incredible climbing skills to search every nook and cranny for food.

There is no doubt that predator control will play a vital role in protecting this precious taonga. That’s why we are calling on landowners and the community to help to keep predator numbers down through trapping. Now is a great time to set and check traps so that we can give invisible treasures like bats a chance to make it through winter.

Contact The Forest Bridge Trust to find out how you can get involved with backyard trapping or volunteering to help maintain a trapline: admin@theforestbridgetrust.org.nz