Loss of Nectar Bats Threatens Durian Farmers


A Cave Nectar Bat pollinating durian flowers
A Cave Nectar Bat pollinating durian flowers

The story of Cave Nectar Bats’ contributions and requirements is complex and only beginning to be fully understood. These bats traditionally formed huge colonies in caves, 100,000 individuals in a single cave. However colonies are extremely vulnerable, and few large colonies remain. People commonly set nets over cave entrances, capturing large numbers to be eaten as a delicacy. Also, limestone quarries pose constant threats of permanent destruction of essential caves, and durian growers themselves sometimes kill large numbers.



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Documenting Billion-Dollar Bats

Cave Nectar Bat pollinates durian.
Cave Nectar Bat pollinates durian.


Dr. Sara Bumrungsri, a leading bat ecologist, invited us to help document the essential roles of Cave Nectar Bats (Eonycteris spelaea) in pollinating some of SE Asia’s most ecologically and economically valuable plants near Hat Yai in Thailand’s Songkhla Province. We set up our bat photo studio in Sara’s lab at the Prince of Songkhla University, caught two cave nectar bats in mist nets set beneath durian flowers in an orchard, tamed them so they would go about their normal activities in Merlin’s enclosure, then brought them fresh flowers so he could photographically document their importance as pollinators.


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Thai Temple Flying Fox Photography

Lyle’s flying fox and pup

Large flying foxes are always difficult to photograph, especially since they’re intensively hunted over their range. But in Thailand there are still several colonies of Lyle’s flying foxes (Pteropus lylei) that are protected by Buddhist monks. The bats have learned that they are safe when close to the monks’ quarters. And by also remaining close to the monks’ quarters we were able to photograph them much closer than usual, though it still required a great deal of searching for just the right individuals.


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Khao Chong Pran’s Bat Economics

Poachers were killing huge numbers of Khao Chong Pran’s bats and selling them to restaurants until guards were hired to protect the bats. In Thailand bats were killed for the restaurant trade before a law made it illegal.

The Buddhist temple at Khao Chong Pran is said to have been built largely from guano fertilizer sales. When Merlin first visited the site in 1981, monks were alarmed by a precipitous drop in guano production and asked his advice on the problem. He discovered that poachers were killing large numbers of bats by setting nets over the cave entrance late at night when the monks weren’t looking. The bats were sold to restaurants as a food delicacy. After Merlin convinced the monks to hire a guard in 1981, bat guano sales increased from $12,500 U.S. annually to $89,000 within 10 years, and by 2002, annual sales had reached $132,000 U.S.  Recently, the guano producing bats had been in gradual decline despite 24-hour protection by a team of four guards, so Merlin was quite pleased to discover several evenings ago that the most likely cause of renewed decline was simple to remedy–remove gradually encroaching vegetation.



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Thailand Bat Cave Revisited

Merlin meeting with the head monk at Wat Khao Chong Pran who was happy to see him again.
Merlin meeting with the head monk at Wat Khao Chong Phran who was happy to see him return.

We arrived at Wat Khao Chong Phran unannounced and surprisingly the head monk agreed to see us immediately on the same porch where we met him with Daniel Hargreaves in 2012 (See Sept. 20 blog Guano happens). Merlin even wore the same shirt, his favorite field shirt! Pongsanant, our BatThai guide and interpreter then and now, told us the monk was quite happy to see us again. We had a short visit and were granted permission to go up to the cave entrance to photograph the emergence. We made an appointment to see him the following morning to discuss our findings.

Merlin at the cave entrance with our guide Pongsanant interpreting, while he explains to the head guard and a monk which trees and vines need trimming for the safety of the bats as they emerge each night.

The wrinkle-lipped bat (Chaerephon plicatus) colony had been slowly declining in recent years, despite protection, so Merlin was concerned to discover why. After climbing to the cave we noticed that trees and vines had gradually grown up around the entrance, disrupting the bats’ emergence, as thousands collided with obstacles. We saw clear problems that in other free-tailed bat caves have caused abandonment and reported this the next morning. Merlin was happy to provide an on-site explanation and delighted when the tree trimming was promptly ordered. The cave managers are now aware that this should be repeated every couple of years in the future as a routine part of protection.

Given Merlin’s involvement in gaining the first protection for these bats 34 years ago, he’s especially interested in ensuring their continued safety.







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Angkor Wat and Bats

Angkor WatLiterally thousands of temple ruins are near Siem Reap to explore, and at least three days is recommended to see most of them. In one day we visited ten, and were pleased to find bats in most of them.

The complex of temples known as Angkor was built from the 9th to 13th century by successive Khmer rulers, and the mother of them all is the Angkor Wat Temple, the largest (first Hindu, later Buddhist) temple in the world. Between the 12th and 13th century, when London had a mere population of about 50,000, it is estimated that Angkor had 1,000,000, making it the largest city in the world at the time.  They were the people, under successive Khmer kings, who built these massive construction projects on the scale of the Egyptian Pharaohs’ pyramids.

If you’ve ever seen the Angelina Jolie movie Lara Croft: Tomb Raider, many of the scenes were filmed at Angkor. I join the chorus and recommend you see Angkor Wat before you die!

At nearby Phnom Kulen National Park, we set up a four-panel bat trap over a small stream in the forest for about an hour, and caught five species of bats. (more…)

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Dawn Bats Pollinating Parkia and Wild Banana

Merlin feeding a Greater Long-tongued Nectar Bat (Macroglossus sobrinus)

On our first day in Hat Yai, after a 20-minute drive from our hotel, we arrived at the Prince of Songkla University (PSU) with Sara and Pushpa. We were given a large lab room in which to set up our photography studio while Pushpa, Pipat and others went mist netting for nectar bats for us to photograph. They returned with two Dawn Bats (Eonycteris spelaea) which were hand-fed by Pushpa and released into the studio for the night.

Pushpa feeding the bats

After midnight, finding a tuk tuk (auto taxi) on campus to get to our hotel was not possible. Pushpa found a motorbike taxi, and Merlin got on with the driver, while I got on Pushpa’s bike. At 2 o’clock in the morning, we had the roads to ourselves.

Logistically, it was difficult to work so far from the bats, so we were offered guest housing on the PSU campus for the rest of our stay. We are grateful to Tuenjit Sritongchuay (a.k.a. Fon), a Ph.D. student, for coming up with the suggestion and personally making all the arrangements. Except when we got locked into the building where we were working or got lost, wandering around the campus at 3 a.m., it worked out really well!

Merlin in a tuk tuk

In the evenings, soon after sundown, we searched for flowers with limited success. We were most interested in photographing bats pollinating Parkia flowers to show the economic value of bats as essential pollinators of the petai or stink bean crop obtained from this plant. It was the end of their flowering season, so they were neither easy to find nor to reach. Pushpa climbed a tree and used a long-handled pruner and carefully lowered the light-bulb shaped flowers down to Merlin and Fon below.

Cave nectar bat (Eonycteris spelaea) and Parkia flower

One night, we went to the mangroves with Sara and two students from Bhutan to search for flowers from the tree Sonneratia ovata. Unfortunately, they weren’t flowering.

Cave nectar bat (Eonycteris spelaea)
Cave nectar bat (Eonycteris spelaea) pollinating a wild banana flower


We needed to keep our bats working, coming to flowers, so Sara brought us flowering stalks of wild bananas. On a previous trip to Thailand, Merlin had taken an excellent photo of a bat pollinating wild banana all covered in pollen, but why not try to improve?

In total, we photographed 22 genera and 32 bat species, a wonderfully successful trip, thanks to many outstanding helpers.










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Farewell Daniel, Hello PSU

bat photography by merlin and daniel
Merlin and Daniel photographing bats in the field

After a rather tense drive from Hala Bala Wildlife Sanctuary through the risky provinces of Thailand’s Deep South on our way to the Narathiwat Airport, we said goodbye and thanks to Daniel Hargreaves for planning and organizing what had been a fantastic field trip. Daniel needed to return home to the UK, but Merlin and I would stay in Thailand for another week to photograph nectar-feeding bats visiting Parkia flowers, among others. The fruit of Parkia is called petai or stink bean. It’s bat pollinated and exceptionally economically important in Southeast Asia.

Sara Bumrungsri
Sara Bumrungsri

To help us get these photographs, we would be working with Merlin’s colleague, Dr. Sara Bumrungsri, and his graduate students at Prince of Songkla University, a two-hour drive north of the Narathiwat Airport in the city of Hat Yai.

Pipat Soisook
Pipat Soisook

While working at Hala Bala Wildlife Sanctuary, we were in the capable hands of one of the Ph.D. candidates at PSU, Pipat Soisook, curator of mammals at the natural history museum on the PSU  campus. Pipat had delivered Daniel safely to the Narathiwat Airport and then Merlin and me to our hotel in Hat Yai. Only five months earlier, an insurgent’s bomb had exploded in the adjoining shopping mall, killing and injuring civilians.

Pushpa Raj Archarya
Pushpa Raj Archarya

At our hotel, we were met by Dr. Sara and Pushpa Raj Acharya, a Ph.D. candidate from Nepal. Pushpa is his country’s first bat biologist. As a matter of fact, before Merlin had left his position as Executive Director of Bat Conservation International, he had organized a special BCI scholarship for Pushpa to study durian pollination by bats. Durian is another extremely economically important fruit in SE Asia.

Sara and Merlin enjoying durian outside the university.
Sara and Merlin enjoying durian outside the university.

It seems to me, durian should be called stink fruit. It’s so malodorous that hotels and airplanes ban it. Yet despite its unpleasant smell, durian has a lot of loyal fans. Dr. Sara is one of them. He enthusiastically bought one to share with us. Merlin is the ultimate frugivore and never met a fruit he didn’t like. Durian was a big hit with him, but I’d rather eat stink beans.


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The Hala Bala Bat Hall of Fame

Just four nights of photography at Hala Bala yielded photos of 18 species of bats, including the rarely seen Naked Bat, the tiny, cute Tailless and Spotted-Winged Fruit Bats. Here are nine of the beauty queens and runners up:

The Naked Bat (Cheiromeles torquatus)
The Tailless Fruit Bat (Megaerops ecaudatus)
The Spotted-Winged Fruit Bat (Balionycteris maculata)
Trefoil Horseshoe Bat (Rhinolophus trifoliatus)
Lesser Hairy-winged Bat (Harpiocephalus harpia)
Malayan Free-tailed Bat (Mops mops)
The Malayan Slit-faced Bat (Nycteris tragata)
The Gilded Tube-nosed Bat (Murina rozendaali)
Least Woolly Bat (Kerivoula minuta)



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In Search of Naked Bats in Thailand’s Deep South

Our destination was Hala Bala Wildlife Sanctuary to seek and, hopefully, photograph the world’s largest insectivorous bat: the Naked Bat, Cheiromeles torquatus.

Narathiwat Province borders Malaysia.

We were met at the Narathiwat Airport by Pipat Soisook, Curator of Mammals at the Princess Maha Chakri Sirindhorn Natural History Museum, and Sunate Karapan, Director of the Hala Bala Research Station.

The research center’s lodging was spacious and comfortable, and we had it all to ourselves, since the usual clientele of researchers were staying away, we were told, due to violence in surrounding areas.

This background about the violence came from the Lonely Planet’s guide to Thailand:  Over 100 years ago, the Kingdom of Siam conquered this area, but an Islamic separatist group wanted to secede from Buddhist Thailand, and independence is still an issue today. Foreigners are not the targets, but can be in danger, as when a market was bombed just prior to our arrival.

The Hala Bala Wildlife Sanctuary was one of the few places where we could reliably find the rarely seen Naked Bat. It was an exciting place to work, where we could potentially run into a tiger, leopard, sun bear or a King Cobra. In the early morning, we were often serenaded by gibbons while eating breakfast. At mealtime, we had to contend with a pet Great Hornbill named Wang, a bird the size of an eagle who tried to dive-bomb us or rob our food, especially his favorite: roti, a type of flatbread.

Merlin gets a love bite from Wang, the Great Hornbill

Next I’ll tell you about our experiences netting and photographing 18 species of bats, including photos of Naked Bats as well as very cute and tiny Spotted-Winged and Tailless Fruit Bats.

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