Bat experts ready for late nights

Our native bats are unique: short-tailed bats fold up their wings and walk on their elbows, and long-tailed bats are small enough to fit in a matchbox.

The first local bat conference to be held in about 15 years is coming to Rai Valley on March 16-19, with more than 20 bat experts presenting papers on New Zealand's only native land mammal.

Its organiser, Forest and Bird regional field officer Debs Martin, said she was looking forward to a presentation focusing on bat populations in plantation forests, as this related to Nelson's forestry industry. She also wanted to hear more about the work being done in Fiordland by bat expert Colin O'Donnell.

Auckland Zoo will give a presentation on the first native bats bred in captivity, which were born at the zoo in November.

Each evening of the four-day conference will end with a bat-catching session. Any bats caught will be fitted with transmitters.

"One of the cool things about a bat conference is that you start late in the morning and finish late at night," Ms Martin said. "The reason why we chose the Rai Valley is because it's fairly reliable to find bats out there most nights."

She said Forest and Bird would speak about the bat recovery project it had been running at the Pelorus Bridge Scenic Reserve since 2010.

The organisation has just been granted funds that will allow it to start working with bats on D'Urville Island next year. "That's really exciting, because our surveys showed that [D'Urville Island] is one of our best chances of protecting bats on an offshore island," Ms Martin said.

She said that if nothing was was done to protect bats, they would become extinct on the mainland within 50 years.

The biggest threat is deforestation, which removes the large, hollow trees bats need to roost in, but predators may pose a growing problem after this year's beech seeding mast.

In a mast year, beech trees cover the forest floor with more than 4000 nutritious seeds per square metre, providing food for a plague of rats. Department of Conservation scientific officer Josh Kemp said the entire South Island could expect to be affected by this year's "massive" mast.

The hunt for Nelson's suburban bats continues at Neale Park, where conservationist Edith Shaw reported sightings of long-tailed bats in August last year.

She said the bats came out when footballers training at the park switched its floodlights on. The lights attracted moths and flying insects, which tempted bats out of the forest.

Ms Shaw said she believed her cloud of bats could be roosting at Founders Heritage Park, but despite several thorough daytime explorations, she has not located their home.

She said that after the Nelson Mail published an article on her discovery, she was approached by people who reported bat sightings at Wakapuaka, the Centre of New Zealand, The Brook, near the Maitai River and throughout Abel Tasman National Park.

"I think there's a lot more bats about than professional people realise."

Ms Shaw said the bats were particularly prevalent on foggy nights. She and Forest and Bird's surveying team near Pelorus Bridge had wondered whether they were using the damp air like a shower, to clean their furry coats.

Ms Martin said Forest and Bird had not detected any bats in the central city using bat locating devices, although this did not necessarily mean they were absent.

She said long-tailed bats had a range of up to 100 kilometres, and it would be easy for them to pass through Nelson.

"What we suspect from a number of recordings is that there might be the odd bat that pops over the Maungatapu saddle from Pelorus.

"There might be a few itinerant hitchhikers in Nelson."