Narcondam Hornbills: Gardeners of their Island Eden

“Could it be rats?” I asked, picking up one of the peels, the inside still wet.

“But there seem to be no gnaw marks,” pointed out Navendu. The two halves, still joined together, fit perfectly like the pieces of a jigsaw to make a hollow globe about the size of a large gooseberry. Someone had with great dexterity cracked open the peel to get at the thin, slimy layer of pulp that coats the large seed inside.

“Or maybe bats?” asked Abhishek.

“Again, no bite marks” said Rohit. We were standing below a Caryota palm (Caryota mitis), our heads together, all at sea, with the peels in question strewn all around us along with numerous, large, shiny grey seeds. And with that we’d run out of the list of fruit-eating mammals on the island. Yes, island, for if the camera was to quickly zoom out and fly far above the thick canopy of the lush tropical forest that we stood in, you’d see that we were actually in the middle of the Andaman sea, on India’s easternmost island — Narcondam.

The tiny 6.8 sq km island is actually a volcano that went extinct long ago and is the only place in the world where the eponymous Narcondam hornbills live — or shall I say thrive? For nowhere else in the world are hornbills found in such high densities. We estimated a total population of around 1,000 birds — that means an average of about 150 birds per square kilometre. And we were here to find out just how such densities were possible.

Rohit Naniwadekar and Abhishek Gopal — who study  the intricate ways in which fruit-eating birds and fruit-bearing trees depend on each other — are scientists with Nature Conservation Foundation, an NGO based in Mysore; Navendu Page is a plant ecologist and a faculty member at the Wildlife Institute of India, Dehradun; and I am an artist. The fifth member of our team was Prasenjeet Yadav, a freelance photographer and filmmaker. Part of a larger collaborative project, the five of us spent time on Narcondam last winter.

We knew that hornbills eat Caryota because there have been reports of seeds from the middens (dung heaps) at nest sites. And we knew that hornbills are extremely dexterous with their beaks. They can pluck tiny berries no bigger than a peanut and toss it into their gullet, then regurgitate it, bringing it back to the tip of their huge beaks and pass it to their partner, all with such consummate skill that it could pass for magic. Their beak, like an elephant’s trunk, serves them as well, if not better, than a hand would.

On Narcondam, we saw how nimble they could be when preening, grooming or playing — the juveniles, especially, would pause while playing, holding each other’s beaks! Watching them day after day, we saw them in all sorts of situations up close, reacting to each other and to their environment. There were even times when I could’ve sworn I knew what they were feeling or thinking. But it’s one thing to express emotions without proper faces, quite another to peel a fruit without hands.

And why would hornbills peel a fruit anyway? I mean, their massive gapes let them pluck, toss and swallow large fruits, right? Letting the stomach juices do their job before regurgitating or dropping the seeds, intact and unscathed, far away from the mother tree.

Where a seed lands is perhaps the single most important factor that determines the fate of the sapling that emerges from it, and so it is dispersal that effectively determines forest composition. Hornbills are excellent seed dispersers owing to the combination of the long time that seeds take to pass through their gut and their wide ranges, which ensures that they’re usually far away from the tree that they were feeding on by the time they drop the seeds. On Narcondam, hornbills are the largest as well as the most numerous frugivores and so over thousands of years they have inadvertently tweaked the composition of the forest to meet their needs. This may have been their isle of exile, but now it is their garden of Eden.

We found veritable orchards of the trees whose fruits they favour, be it the soft barked Discospermum with fruits the size of small plums ripening red like cherries or Chionanthus, with its elongated fruits that go from green to blue starting at one end as if dipped in ink, or figs, whose density was two to ten times higher than that in other comparable forests that harbour hornbills.

And then, of course, there’s Caryota mitis. The fruits of Caryota grow like tiny decorative light bulbs on whip-like chords that hang down, clustered together to look like a chandelier. The whole infructescence may have thousands of fruits but only a fraction will ripen every day, going bright red — like bulbs turning on, one at a time. Each fruiting palm can have two, three or more chandeliers, each at a different stage, so that one can see dry, twisted chords completely devoid of any fruit, a full chandelier and an inflorescence all on the same palm.

We wanted as complete a picture of the island’s ecology as we could manage in the two months that we were there and so we had our work cut out for us. We started with vegetation sampling to understand forest composition and walking more-or-less straight trails through the forest to estimate bird densities. A few weeks went by like this and we were yet to find the mysterious peeler.

Gradually we turned our attention to seed plots to estimate how much damage rats were causing the fallen seeds, and supplemented our trail walks with six-hour long tree watches to ensure we weren’t missing out on any sneaky fruit-eaters during our walks. Then one fine day, as we were laying a seed plot under a Caryota, a few hornbills landed right above us.

Slowly moving our heads to get a good view of the birds through the thick understorey and the spreading leaves of the palm, we saw them perched on top of the chandeliers. It took us all a moment to figure out what was going on. They’d pluck a fruit, toss it, hold it, toss it, and just as you thought they’d dropped it, they’d be swallowing something — while something surely also fell. The hornbills were peeling the fruits!

They pluck a fruit, position it to one side of their beak and press down until the peel cracks and the fruit pops out. At that instant, they drop the peel and catch the fruit mid-air!  And all with a nonchalance that would put a professional juggler to shame.

I imagine young hornbills learning the trick from their parents, just as they learn from them to keep track of when the various orchards that they have all over the island are in fruit. Until slowly, over the years, they get to know every nook and cranny, each ridge and valley, of this magnificent island to which they belong and which, in turn, belongs to them.