Saturday, December 16, 2017

The Oilbirds of Dunston Cave


PERCHED: A nesting adult Oilbird.

(BI) Feedloader User


follow the trail: (At top) A shot of one of the AWNC's nature trails. —Photos courtesy: HAROLD DIAZ

(BI) Feedloader User

JUST as sites deemed holy and sacred lure thousands of pilgrims from every corner of the world each year, the Asa Wright Nature Centre has, for over four decades, enthralled die-hard bird watchers who travel thousands of miles just to scour the length and breath of the nature centre, with binoculars in hand, intent on spotting some of the hundreds of flora and fauna species at the centre. However, the AWNC is more than just a place for rest and relaxation and a hotspot for avid bird watchers.

Beyond its' world famous verandah is Trinidad's rainforest.

The nature centre's nature trails—which range from mild to adventurous—opens up to a world of lush green vegetation, stretching upward, competing for the sunlight. Tall trees with outstretched branches form a canopy overhead and down below brown leaves carpet the ground, still damp from a light shower moments earlier. On this occasion, the Express was invited to visit the Dunston Cave — home of the rare Oilbird.

On the way to the cave, we spot a Gold Tegu (large lizard) in the process of shedding its skin, laying in sort of a trance on the edge of a trail. Further along the trail, we come across a wild tobacco tree and a sandbox tree which has a smooth bark riddled with many dark spines. While the thorny bark wards-off predators, it attracts birds wanting to protect their nests from snakes and other creatures.

Not only are some of the trees and plants at the nature centre unusual, if one were to be on the trails at just the right time, one may spot the strange, yet fascinating antics of the white-bearded manakin, a small black and white bird with orange legs and a chest as white as snow. In a gathering of males or communal lek, the male white-bearded manakin tries to woo its female counterpart during a one-of-a-kind breeding display.

The male white-bearded manakin clears a patch of ground, then perches on a branch. The male would make mad dashes from the branch to the ground as part of his display which isn't complete without his signature display song. While the white-bearded manakin performs his antics close to the ground, the golden-headed manakin can be seen high up in the trees where it makes rapid dashes to and from its perching branch; it then slides back in a move reminiscent of the moon walk. For extra measure he will perform the routine over and over again until he successfully attracts a female.

As we approach Dunston Cave, expectations rise, and the fearsome shrieks of the oilbirds takes our minds away from the sound of rushing water flowing through the cave. The oilbird — which is the only nocturnal fruit-eating bird in the world, was first described by German explorer Alexander von Humboldt in 1799. Today this rare species can be found in this country as well as in Guyana and the South American countries Venezuela, Colombia, Ecuador, Peru and Bolivia.

According to head guide at the AWNC Mukesh Ramdass, young oilbirds weigh twice as much as its parents. Indigenous Amerindians collected the fat nestlings which were then rendered down for their oil. The oilbird's owl/hawk-like appearance, combined with its eerie screams would hardly earn it first prize among cute and cuddly creatures. But whatever the oilbird lacks in the looks department, they make up for it with their amazing abilities.

In a booklet on the oilbird compiled by Ian Lambie for the AWNC, Lambie observed that the oilbird has unique eye features; they also use low-frequency sonar signals which are audible to the human ear. When on their nest-ledge and in total darkness, they use their rictal bristles to feel their way around. Its powerful bill makes it easy for the bird to pluck fruits from trees with a high oil content such as palm and avocado trees. The oilbirds' powerful long wings and extraordinary sense of smell also make them efficient foragers of food.

These birds are protected under the Conservation of Wildlife Act, but some have succumbed to the hands of poachers, noted Lambie. At the Dunston Cave, the oilbirds are carefully monitored and as a result, their population has grown in the last 10 years, said Ramdass.

"It is very important to restrict the number of visitors to the cave because in the past the cave was disturbed by humans and the birds all left the cave at one time. That is why we have two trips to the cave per week," said Ramdass.

The Dunston Cave is the only oilbird habitat in the world where a data count is done every month. As of the last data count there were 164 adult oilbirds, eight chicks and eleven eggs.

"I have been taking the oilbird data count for the past 15 years. It is done by at least three persons. We have to take a long ladder, flashlight, pen and paper and a bucket for collecting seeds. The count lasts for about three hours. We start from the bottom of the cave and work all the way to the front of the cave. After the count we collect regurgitated seeds and give them to the gardener," said Ramdass.

The seeds are then planted at the nature centre, thereby ensuring that the oilbirds never have to venture far beyond their natural habitat for food. Ramdass noted that the oilbird colony at the nature centre is the most accessible in the world. The oilbirds of Dunston Cave are just some of the hundreds of creatures waiting to be discovered at the Asa Wright Nature Centre.