A study full of books and pictures of birds is the weekday workplace of Dr Pilai Poonswad. On weekends, the renowned biologist and emeritus professor at the Microbiology Department of Mahidol University moves her “office” to the dense forests, where she has spent days and nights researching hornbills for 37 years.
“My interest in birds came to me by accident,” she recalled of the time in 1965 when she was first introduced to the avian world, when working with the late Dr H Elliott McClure, an eminent scientist, for his Migratory Animal Pathological Survey project.
“The late Dr McClure was like my godfather,” said the scholar. Together with her mentor, they visited Khao Yai National Park, which was where Pilai saw hornbills for the first time. Dr McClure wrote a scientific article about the birds for the Natural History Bulletin of Siam Society (published early 1970). Some years later, Pilai was contacted by a BBC documentary team to help locate hornbills in Khoa Yai for its series Safari To Thailand: Fig Feast At Khao Yai.
This was a good decision as Pilai was a hike leader for about 10 years, ever since her student days at the Faculty of Education in Chulalongkorn University. It was during this time that Khao Yai became like her second home.
Unfortunately, however, she roamed around the forest with one ranger for a week, but they came out empty-handed. She tried again by finding a fig tree with ripe fruit, the food of hornbills. This time, she found the rare bird within two days.
“It’s very beautiful and very impressive to see the big bird taking the ripe fig fruits,” she said. A couple of months later, she found a hornbill’s nest cavity in a tall tree. She remembers that it was like winning the lottery. She and the ranger came back a day later to observe the birds.
After hours of waiting, a male bird came back to the nest. While it was about to regurgitate the fruits to a female bird, it suddenly noticed Pilai and the ranger and became distressed. It cried out loud, broke some tree branches and swooped at them, attempting to chase them away.
The pair waited until late noon feeling remorseful that maybe the female bird would be hungry as the male had refused to return to the tree. Pilai and the ranger decided to quietly leave the spot.
That experience inspired Pilai to learn more about the hornbills, an ancient species that has roamed the Earth for nearly 50 million years (see box). Using her own budget and with support from her friends to establish the Thailand Hornbill Project in 1978, she started following and keeping data of the first couple of hornbills she found at Khao Yai. Today, at 69, Pilai still goes on the field looking for the majestic birds that have become part of her life.
The great hornbill always stains its wings in yellow with oil from its preen gland.
Into the Woods
As a malariologist and an expert on bird parasites, Pilai has to manage her time between her classes, being in the lab, and her ongoing hornbill research. Back when she started out in the field, she had company. One was her Japanese friend, Atsuo Tsuji, a mathematician of Japan’s Meijo University and an expert in observing shorebirds who helped Pilai take pictures of hornbills. The other was the late Boonma Saengtong, a ranger of Khao Yai National Park, who helped Pilai locate hornbill cavity nests and, at times, protect her from unexpected harm. They would often run into herds of gaur, wild elephants, bears and even cobras.
“While on the field, I never thought of danger as my focus was on the hornbills,” she said. In the field, Pilai can wait in silence for more than 10 hours a day and trek all day in the forest with a backpack that weighs around 20kg, almost half her weight, which has, unfortunately, caused her back pain for many years.
One day in 1984, while she was in the field alone, her legs became semi-paralysed. She had to crawl back to the camp before nightfall. There, she was rushed to hospital and was diagnosed with a degenerative disc disease. For the next few years, she had to swim everyday to bring the strength back to her legs.
This kind of demanding physicality has been part and parcel of her lifelong work, as well as the countless hours spent recording and analysing details about the birds. Pilai recalls the first time she hid inside a bird hide — a camouflage shelter — to observe the bird’s cavity entrance in the next branch. She covered the hide with a piece of large, black cloth and sat holding her knees to her chest for hours. A female wreathed hornbill eventually went inside the cavity and Pilai saw it survey the cavity and fly up to the ceiling. That was when she found that the height of the ceiling must exceed one metre to allow for air ventilation and an escape route if there is a predator, while the floor is around 10-15cm lower than the entrance edge as it is then easier for female and chicks to reach for food fed by the male bird.
While watching the activity, the male bird came back to the tree and landed on the vine. Its powerful grab shook the whole tree.
“The female bird fell down to the cavity floor and found my eyeglasses behind the peek hole. It might be instinct that the bird used its beak to grab my black covered cloth until it filled up the hole and flew away,” she said.
Pilai came back to the tree on the following day. This time she hid behind an observation blind on the ground. She wanted to see how the big bird passed through the small oval shape of the cavity. Instead of quickly getting inside the nest, the bird flew around the tree and observed for a couple of hours. “After the incident, I knew I had to be cautious. The bigger the bird is, the more careful it will be,” she said. She managed to take pictures of the bird when it slipped in sideways, firstly with one wing, then it pushed the body by using feet scrabbling for traction.
Behind the observation blind, she recorded every activity of the birds, including the types and amount of food the female was fed and the time spent on feeding, and throwing out broken nest plaster.
A rare-to-find helmeted hornbill.
And the Wild
The hornbill, whose unofficial population numbers around 3,500 in Thailand, with some genus categorised as endangered, is an endless source of biological and behavioural knowledge. For instance, the male always takes full responsibility of taking care of the family. When the male feeds the female, it regurgitates each fruit stored in its expanded oesophagus one by one and feed her bill-to-bill. The process is very quick, she said. Every day, a large hornbill can eat up to 400g of food and it mainly eats ripe fruits, but also needs protein from animals like insects, lizards or squirrels, when the female molts and when the chick hatches from the egg.
“If the male brings a snake to the nest, it takes a lot of energy,” she said, adding that it often looks very tried. It tends to take a rest, like a quick nap on one branch before flying away for more food again. Sometimes, the female can be fussy. It might be because the male keeps feeding only ripe figs to her until she gets bored with the fruit and so refuses to eat it. Often, the male has to change the types of fruits to please her, Pilai recounts, laughing.
Pilai and her team also studied the home ranges of hornbills. With a limited budget during the early period, they used radio telemetry for tracing the birds and later upgraded the tools to GPS transmitters. The data revealed that the great hornbill covered about 600km² of forest while the wreathed hornbills covered about 880km².
Her research scope covered forests throughout the nation with specific focuses on Khao Yai National Park, Huai Kha Khaeng Wildlife Sanctuary and Budo-Sungai Padi National Park in the south.
“I was very excited when I saw a rare species of helmeted hornbill in Si Phangnga National Park in Phangnga and rhinoceros hornbill [believed to be extinct] in Budo forest,” she said. In Budo, she was informed that some villagers were poaching hornbills for a living. One chick could cost up to 20,000 baht, especially the rare white-crowned hornbill.
Dr Pilai and the team captured the hornbill by using a mist net to attach a radio telemetry for the home range study.
She approached poachers in nine villages near the park, educating them about hornbills and asked them to be part of her conservation team for field researches. They would receive a salary in return for their field data.
About 10 years later, she established Budo Hornbill Conservation and Education Centre. More than 40 people are now members that keep their eyes on hornbills and their nests. She succeeded in turning hornbill poachers and illegal loggers to hornbill protectors.
Her research team also inspects nest cavities and repairs nests, such as adding soil to raise the floor, enlarging the cavity entrance and creating new nests. This also makes a huge contribution to increasing the population as hornbills can’t carve out their own cavities. In Khao Yai National Park, the bird population has increased more than three-fold. The research team found more than 1,600 chicks and about 500 chicks each for Huai Kha Khaeng and Budo-Sungai Padi during the past 30 years.
Her contribution to hornbill conservation has been widely recognised, not only in Thailand but also throughout Asia. Her team helps train team researchers in many countries, such as Malaysia, Bhutan, China and India.
“I am proud of my team and the work we have done so far. Our hornbill research is the most in-depth in Asia. The hornbill research project is not only for us, but for our country to be proud of,” she said.
