Fruit bats lost and found: mixed news from the first roosts of the survey

The period in the run up to the start of these surveys proved that even the most thorough plans are made to be adjusted and readjusted… first it was me breaking my toe, and then it was torrential rains just as the ‘dry’ season was supposed to be starting. But finally we were ready, and could get started on the surveys. As we were already behind schedule, there was no time for a slow warm up so we launched straight in, covering four roosts in the first week.

Livingsone fruit bat research team

Daniel, Ishaka and Amelaïd tucking in to bananas and fish

We set out all together as a team of four: Ishaka, Daniel, Amelaid and I, so that we could refresh the methodology together, making sure that we’re consistent in the way we count the bats at each roost. For the next outings we’ll split into two groups so we can cover all fifteen roost sites in Anjouan in as short a time as possible, to make sure the results are comparable (it’s not a good idea to compare a count from June with a count from September for example, as the populations at each roost fluctuate throughout the year).

Before starting these surveys we studied roosts over a whole day to work out the best time to carry out our counts – we want to count the bats at the time when the roost is busiest. We found this was between 8am and 11am when the bats are resting before they set out to forage in the afternoon. So normally we slog up to the roost in the late afternoon, and set up camp not too far away so that we are in place and ready to start the count in the morning.
It’s been a while since we were all in the field together so sprits were high as we set off up the mountain to the first roost in Salamani. But after the sixth person passed us heading down from the forest with huge planks of wood on their heads we knew this wasn’t a good sign for the bats.

When we got to the roost we found it had changed a lot since our last visit in December: more crops had been planted directly under the roost, and a whole new banana field had been cleared nearby. It really shows how quickly the landscape is changing. Ishaka has been counting the Livingstone’s fruit bats for over 15 years and remembers this site to have been dense forest only ten years ago. Since then, as well as agriculture moving in, some of the original roost trees have been felled. The bats have moved slightly away from the intensifying agriculture, but luckily they haven’t abandoned the main roost tree.

Forest clearance Anjouan Comoros

The newly cleared banana field by the Salamani roost

After checking out the roost we settled back down to the all too familiar field rhythm of setting up camp and eating our dinner of cold fried fish and bananas, before bedding down in our tents to be ready for the morning counts.

In the morning we counted only 40 bats, which is worrying as we counted 97 during the wet season; the bats don’t seem to be coping well with the disturbance around the roost. With the first count behind us I was slightly relieved: I seemed to remember the climbing being harder last time… However part way back down and the familiar shaking knees returned as I slid down the slope. It’s the downhill that always gets me.

The next day Ishaka and I set off for the roost near the village of Ouzini, a village high in the mountains, an hour’s walk from the nearest road, while Daniel and Amelaid headed off to count the roost near another mountain village called Outsa.

Landslide Ouzini

This landslide tore through a farmer’s field in Ouzini

Livingstone fruit bat roost hit by landslide Anjouan Comoros

The landslide that swept right by the Livingstone’s roost at Ouzini but luckily didn’t hit any of their favourite trees

Back in May the island suffered from some terrible storms, with flooding wiping out many houses, roads and water supplies. The equivalent of a whole year’s rain fell in four days. The area around Ouzini is particularly steep, even for Anjouan and suffered many landslides following the flash floods. It was quite something to see the boulders that had been carried down the slopes, obliterating entire fields and some farmers’ entire crops. By the time we got there though we found villagers hadn’t wasted any time in planting banana plants in the newly turned soils.

Ishaka and I were not ready for what awaited us at the Ouzini roost. One of the landslides had swept right through the centre of the cluster of trees the bats roost in. This site is so steep that the trees are not likely to be targeted for construction materials because there’s no way of carrying the planks out, but they were hit by storms instead.

By some small miracle the landslide had missed the particular trees the bats choose for roosting and we found 72 bats in the same 14 trees that we did back in December, much lower than the 105 from last time. The field owner was busy chopping up the fallen trees for firewood, creating a lot of noise in an area which was previously undisturbed. We don’t know how the change in physical environment will affect the colony, but fingers crossed when the noise stops, it will be calm enough for the other bats to return again.

Mongoose lemurs Anjouan

Inquisitive mongoose lemurs came to see what we were up to as we were searching for the new roost

So it was depressing news from our first two sites, but every cloud has a silver lining and back in the village of Salamani we heard rumours of another roost that has previously never been counted, found far, far into the forest. So we were all excited to explore further into the forest in the hope of discovering more bats.

We had been warned that the new roost was far away, but after an hour of scrabbling up an incredibly steep slope I started to wonder if it would be my heart or legs that would give out first. We finally found nine big black bats lazily dangling in a forest tree. Even though it’s a small number it’s a relief to find a new site, and this brings the total number of roosts in Anjouan up to 16.

Livingstone fruit bat roost Salamani Anjouan Comoros

The new roost we found deep in the forest above Salamani

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