Bat population down 84 per cent

Cayman’s common fruit bat population might have been reduced to about one-sixth of what it was before Hurricane Ivan in September 2004. Two other types of bats previously found in Cayman have not been seen at all since then.

Fruit bat

This juvenile female has calmed down after being caught in a net, allowing her head to be petted. Once wildlife biologist Annie Band has recorded her data, the bat is released. Photo: Carla Reid

Local bat expert Lois Blumenthal said the lower numbers of bats could affect the ecosystem.

‘Bats are crucial to a healthy ecosystem,’ she said. ‘Without bats for insect control, we see imbalances like the current losses of so many beautiful old fig trees, which survived Ivan only to succumb to the onslaught of a particular caterpillar population explosion, probably due to the losses of birds and bats.’

The findings concerning the bat population are two preliminary conclusions of Annie Band, the wildlife biologist who visited Cayman last month and compared her findings to studies she did pre-Ivan, the latest in 2002.

People who are afraid of bats or who blame them for damaging crops may not care about the fate of bats in these islands.

But that would be a mistake, Ms Band said.

For example, she said 90 per cent of the fruit bats in Cayman and 99.9 per cent elsewhere eat only fruit that is overripe – past the point of being harvestable. They do not, for example, eat unripe naseberries, Ms Band emphasised.

The bats are very important ecologically because they pollinate plants and disperse seeds.

Ms Band was saddened not to see any white-shouldered bats or buffy flower bats this visit, even though she checked numerous sites at which she had found them previously.

After Ivan’s winds stripped and downed trees, the bats may have found it difficult to survive without flowers and fruits to eat, even if they shifted their diet to what was available, she explained.

Insect-eating bats have fared better. Although many were killed in the storm, those who survived had plenty of food because the insect population exploded after the hurricane.

Ms Band, who teaches and does research in Wyoming, U.S.A., was on her fourth visit to Cayman. Her trip was sponsored by the National Trust for the Cayman Islands, the Department of Environment and the Darwin Initiative – a grant for studying the variety of local wildlife.

Mrs. Blumenthal and her husband Jim provided housing and a vehicle so that Ms Band could check all areas of the island. By day she explored caves. At night, sometimes past midnight, she kept vigil in dense bush or on farmland, with owners’ permission.

Ms Band counts bats by setting up a device that looks like a finely meshed volleyball net. When bats fly into the net she gently extricates them, wearing thick leather gloves. Each one is checked for sex and level of maturity, then weighed and measured.

Ms Band then snips off a tiny strip of a wing before the bat is released; the strip is carefully stored for future DNA analysis. The cutting does not seem to hurt the bats for they regularly tear their wings on the twigs of trees or rough terrain surfaces, but the damaged area grows back.

Mrs. Blumenthal, known as ‘Miss Lois the Bat Lady’ because of her own bat conservation efforts, had strong words of praise for the visiting scientist and her mission.

‘I always look forward to Annie’s visits,’ Mrs. Blumenthal said. ‘She is tireless in the scientific documentation of Cayman’s rare bat species and a huge help in getting the conservation message across to the public and the government.

‘We expected Annie’s findings to be discouraging, especially for the fruit and flower bats, and so it was, but we were glad that she did find evidence of some species’ survival in cave systems, and I think that her message that we must preserve the islands’ caves cannot be overemphasized.

‘Countries like Guam and Israel have lost their bat populations and are now suffering fairly severe environmental consequences.’

Mrs. Blumenthal believes Grand Cayman’s bats need help.

‘Despite Ivan, Cayman still has a chance to save our remaining bats, but without cave and forest conservation, backed by serious funding from government or private donations, wildlife like bats and birds won’t survive, and humans will suffer as a result.’

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