Archive for the ‘Bats’ Category
The last month has seen me back behind my laptop dealing with excel spreadsheets and data analysis. It must have been my karma for the wonderful months spent roaming tropical paradise on Pemba Island. I pinned up some maps of Pemba and pictures of the Flying Foxes on my wall, to help me remember them, as believe it or not – I miss observing them. They are full of such character and really are fantastically interesting creatures. Occasionally I see seed pods in the trees in the UK and my eyes are so tuned into bat searching that for a second I might forget where I am! If I miss seeing the bats around, I cannot imagine how much Pemba would do so, if they had become extinct or reduced to such a critical level, as was once imminent. The bats are such an important part of the Island. They have played a role in pollination and seed dispersal for many years, which is evident when stumbling across mango trees in the most remote and sparsely inhabited areas – it was not people who planted these trees, but the bats! They are part of the history and culture of the Island, whether as magical spirits in legends, as a traditional food source or as forest regenerators, they define Pemba and now make the perfect flagship species. Kidike Roost. How many bats can you count! Photo J. Robinson Conservation of this species on Pemba has been a success story. The last few months of research have revealed an absolute minimum population of 18,000 Pemba Flying Foxes! This might sound like a lot, but it is important that we don’t give up on these bats as they are still in danger from habitat loss and hunting, amongst other threats. It is the local communities who live side by side with the Pemba Flying Fox and have been working to protect it. This is not always straightforward to do so during times of poverty, when food is scarce and with little alternative means of income. When you look up Pemba Island on the internet you read about a lush green island with fantastic diving, spice tours and secluded pristine bays, but what I think helps make the island so special is this wonderful Endemic Flying Fox. It would be a shame if anybody visiting the island didn’t drop in to visit the Pemba Flying Fox and in doing so support the communities who are working hard to secure their future (bats and people)! Children on the beach, Pemba.
Photo J. Robinson Welcome sign at Kidike Pemba Flying Fox roost. Photo C. Farese Evening view of Pemba Island
Photo C. Farese
I noticed a behavioural response amongst the Pemba Flying Foxes that intrigued me. The bats natural predators on Pemba are likely to be birds of prey, and humans. I saw the bats exhibit the behaviour twice; once when a bird of prey swooped in close to the colony from above, and once when my field assistant approached the edge of the colony from the ground to take a GPS reading. A large number of the bats simultaneously opened their wings, and the movement travelled across the colony like a Mexican wave. Now it could be that they were just preparing to take off if the threat was considered great enough. But it appeared to me that it may have been a defence mechanism and they were flashing their wings and revealing their russet chests to appear bigger, and startle the predator. I would be interested to know if anyone else has observed this behaviour in Flying Foxes. Pemba Flying Foxes stretching in mid day sun Photo kindly provided by Denise Déziel
Last night we visited Ngezi Forest for the second time to search for the Pemba Flying Fox roost known to be within the vicinity somewhere. On the first visit, we failed to locate them in the thick forest and it had also been raining heavily which may have caused them to hide. Ngezi forest is the largest remaining indigenous forest tract in Pemba and is representative of the type of vegetation that was once thought to cover much of the Island. It is a majestic place full of tall old trees and a thousand shades of green. The understory and vines make hiking difficult if you venture off the path – which of course the Flying Foxes do! The forestry ranger at Ngezi prepared in advance for us to find the bats and managed to locate them before hand – he is an expert tracker and knows the forest very well as you could easily get lost without him. After 40 minutes hiking we located the roost. Inside Ngezi Forest Photo J Robinson In some areas the bats are quite nervous and will take flight at the scent of humans, but here they obviously felt safe enough and protected by the powerful old forest, as they hardly noticed our arrival. They kept their wings wrapped tightly around them as if in sleeping bags. Whereas in most of the graveyards where the bats roost, they chose the tallest emergent trees with the thickest vegetation and often cluster together, in Ngezi they were scattered on low trees with empty branches. The foliage appeared to have been stripped off the branches by continual use and these branches were bent like coat hangers from the weight of the bats. After making a patch count estimate of the bats and admiring some more of the tall trees on the way out we positioned ourselves for a night count. Again our ranger took us to the perfect position to get a great view of the emerging bats. Pemba Flying Foxes roosting on denuded branches within Ngezi Photo C. Farese Ngezi forest was a hive of activity as night fell, the frogs started calling in their remarkably loud voices, bush babies emerged from their daily hiding places and started bouncing about the trees – possibly bouncing into each other judging by the surprised and angry exclamations they were making! As the bats started emerging we had to check ourselves for not mixing them up with the silhouetted birds that were also flying at this time. We witnessed one bat make an extremely fast and dramatic dive to avoid a duck – which was a surprise divergence from their usual relaxed, straight and powerful flight. We counted 834 of the flying foxes on this evening, and are approaching a total population count for this vulnerable species.
I read in a paper by Enwistle and Corp (1997) that the Pemba Flying Foxes like roosting in graveyards – and I can now understand exactly why! There is a graveyard in most villages, and it is the only place which is usually completely undisturbed. The people here believe that if they disturb the graveyard and cut the trees, they are disturbing their ancestors sleep. The graveyards are an absolute heaven for animals as we have discovered as it is here that we have met chameleons, snakes, and most of our bats and monkeys. The trees are so tall, thick in foliage and covered in climbers – that they resemble green skyscrapers, and the whole graveyard is like a fantastic green city. Unfortunately because these graveyards are so close to human habitation they are still subject to some disturbance. Agriculture and plantations often reach right up to the graveyard edge with no buffer zone. The bats are protected in these areas and are also in a great position for finding fruit where people are planting them, but it’s uncertain how long these graveyards will remain undisturbed. Typical village graveyard acts as a wildlife refuge Photo J. Robinson
The socio-economic interviews have been really interesting, and are a nice opportunity to sit down with the villagers and take a break from the hot sun. We have been talking to three main groups of people; the conservation club members that have been set up in some areas around important roosts, the wider public, and school children (who are considered principal players in the future conservation issues of the island). We are discussing general knowledge on the flying foxes, intriguing stories, and key conservation issues. The fluffy bodies, great wings, and mysterious behavior of the Flying Foxes causes some degree of confusion. A few villagers have proposed that that the flying foxes are half birds and half mammals, because of their ability to fly. Some children have even described them as big insects. Most however, know that they are mammals, as they produce young and generate milk like other mammalian species. We are hoping to make a general assessment of fruit damage by the bats and assess through these interviews the possible conflicts with man where the bats feed on these fruit crops. This may have an important implication for the future conservation of the Pemba Flying Fox if the numbers continue to increase. We are also discussing what control measures they have for problem animals on the island. So far it seems that the people think that the bats do cause some damage but other animals, such as monkeys and bush babies, cause more severe damage. The Flying Foxes especially like mangoes, jackfruit, bananas, bread fruit and papaya – which are of course all fruits used by the local population to eat and sell. However they only really eat fruits such as mango when they are very ripe. Many villagers therefore have the opportunity to harvest the fruit in time, and whatever’s left then goes to the bats! The Pemba Vervet Monkey (or green monkey), locally called ‘tumbili’ seem to cause the most problems – as they not only eat fruit but also raid other staple crops such as cassava. It’s a tough situation when you have people and wildlife competing for resources – especially on islands where the pressure for land can be intense. We’ve met a few troops of these monkeys on our travels looking for bats – they normally end up positioned in a tree appearing to shout abuse at us. Although this could be in response to one of our team members realistic ability to make monkey noises at them in the first place!
Being nocturnal, darkly-coloured and fast fliers, bats are notoriously difficult to count! The trees here on Pemba are large and thick in foliage which also makes counting a hard task. Because of the difficulties in counting the flying fox roosts, last week we decided to test some different methods of counting. We will be comparing the numbers we get from the evening dispersal counts with our patch count estimates to get an idea of whether there are any major over or under representations in the methods. Evening dispersal counts are conducted at night as the bats leave the roost to forage. The teams take up positions around the roost with good view of the dispersing bats and wait for them to take flight. Yesterday we were in the South of the island watching a roost of approximately 1500 Pemba Flying Foxes. As it started to get dark and the sky was turning red, the animals started waking up. During the day they are often still and inactive, and because of their rusty coloured fur and black wings wrapped around them, they look almost like dead leaves or seeds hanging from the trees. This evening they really came to life and became quite animated and thoroughly enjoyable to watch. They started stretching their wings, scratching, and the occasional friendly squabble would break out amongst the odd individuals. A few individuals started flying in circles around the roost – perhaps testing the conditions or communicating with the others. However as soon as the sun had set, they took flight, as if on a serious mission. They fly powerfully and fast, and within about 20 minutes, they had nearly all gone apart from the last dots in the sky. What a wonderful experience! Bats take-off after sensing danger
Photo C. Farese
Work is continuing at Kidike roost. This week the toilets are expected to be finished, becoming the first roost site with facilities! The staff here are always welcoming and proud of their roost. The roost is little bit different to many of the others on the island. The species of trees the bats are using are smaller and sparser, meaning this is a great place to get a good view of the bats and if you’ve got a good camera – even a good photo of these beautiful animals. This week we will be helping the environmental conservation club at Kidike to translate their new information brochure into English from Swahili.
First I want to say how happy I am to be working with these wonderful animals, and in such a beautiful place! The first time I saw flying foxes was in a forest in Northern Madagascar – they completely enchanted me and I remember thinking how much I would love to work with them in the future! And here I am. Counting all the Flying Fox roosts on the island is no easy task I can assure you! The flying foxes don’t always stay in the same roost, but regularly shift between sites and move according to season. The bats also roost on steep ridge tops, in thick forest, in mangroves, and on some of the small islets surrounding Pemba. It’s hard to predict when they are going to move – so we have to try and cover as much of the island as quickly as possible, to minimize the chance of double counting some of the bats or missing them completely. Without radio tagging these animals, much of their movements remain a mystery. The infrastructure is basic on Pemba Island, so some of these sites take a long time to reach by car, driving slowly to avoid the pot-holes and hoping it doesn’t rain and turn the whole road into a mud slick! Pemba Flying Fox in flight Photo J. Robinson As part of this project we are not only completing a comprehensive survey to get a recent population estimate and mapping the distribution of the Pemba Flying Fox, but we are also spending time talking with the community, to try and gage their feelings and attitudes towards the Pemba Flying Foxes. As flying foxes eat fruit, seeds and nectar there is potential for them to be viewed as pests by the local people – for damaging their fruit crops. Although so far the opinions are mixed, many people here seem to appreciate the role of the Pemba Flying Fox as a primary seed disperser, and they are often proudly referred to by the local people as ‘tree planters’. In many places the conservation education the DCCFF have been working on over the years appears to have been very effective in increasing understanding of the importance of these animals to this special island. First of all I must apologize for the lack of updates! The last couple of months have been very busy in the field. Since the arrival of our volunteer, we have been conducting a comprehensive survey of all the Pemba Flying Fox roosts on the island. Janine is studying for her MSc in Applied Ecology and Conservation at the University of East Anglia in the UK, and is going to be updating this blogg for the next few weeks while completing her research project on the island. So far things have been going great, apart from a few delays with fuel, power shortages and some heavy rains work has been continuing successfully. Hello everyone, am sorry I have been away for so long. I got really sick and couldnt do very much but I am now better and can now work. I decided to post a few facts about the Pemba Flying Fox for those who have never really heard of it or seen it.
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