“It is not the strongest of the species that survives, nor the most intelligent, but the one most responsive to change.” When Charles Darwin first wrote this line, summarising his theory of natural selection, he made the observation based on natural changes occurring in habitats and ecosystems that led to small adaptations in species for survival.
However, in the modern world, where man-made practices have overshadowed natural changes and eradicated much of the natural conditions of ecosystems, survival of species is still dependent on their responsiveness to this change. Here is one of the many examples.
The life of every Indian Grey Hornbill begins inside a tree cavity, which is dexterously chosen and cleaned by its parents, well in advance. The mother hornbill stays inside this cavity sealing the entrance with mud and her excreta. A small slit-like opening is made, which acts as a passage for the father to deliver scraps of food, for next four weeks. This ingenious ‘maternity home’ is devised to keep the fledglings safe from larger birds and snakes. But what happens when there are no trees? Drastically reducing tree cover is eliminating such natural cavities, putting the lives of many hornbills in danger. But to make up for the losing tree cover, the hornbills in the new urban jungles have devised an alternative plan — building their nests and raising the young ones in the same way humans do — inside concrete walls!
When ornithologist Ajay Gadikar began studying the adaptive behaviour of these birds in the cities of Madhya Pradesh, little did he know that he would discover drastic adaptations.
Ajay found that a pair of hornbills in Indore, created a nest inside a cavity of a wall, around three inches in diameter and 20 feet above the ground. The female hornbill had sealed the window leaving only a small opening, just like they would do in a more natural setting. “I observed the nest regularly for around 10 days and found that the nest was occupied one-and-a half months before the chicks arrived. I could hear the chicks’ call for food, as and when the male hornbill came to feed,” he said.
What added to the researcher’s amazement was the newfound ability of the hornbills to live in an area frequented by people and bustling with activity throughout the day. In the wild, the hornbills would shy away from humans and pick a nesting spot that’s not fairly visible to an observer’s eyes. But in the heavily populated city centre, where there’s little chance of escaping prying eyes, the hornbills have nested and kept their activities going on without drawing attention to themselves.
Around 40 per cent of the diet of these hornbills is comprised of the fruits of the fig tree (pipal), closely followed by the fruits of the banyan tree. But there has been a drastic shift in their diet too. A couple of years ago, the same research team, in collaboration with the Madhya Pradesh Forest Department, had discovered how the birds had taken to eating rotis and bread instead of their natural diet of fruits. “For the first time, it was observed that Indian Grey Hornbill fed pieces of chapati and biscuits that it collected from nearby residential complexes and garbage bins to its newborns,” said Ajay, who placed a closed-circuit camera near a hornbill nest to record the daily activities. “Adaptation is the key to survival and hornbills seem to be doing the same,” Ajay said.
It is an uncomfortable thought to imagine what the world will look like and how many of the present animals and plants will survive the onslaught of the rapidly urbanising planet. But the Indian Grey Hornbill has found a way. Concrete nests and processed food might not be the lifestyle they had known in the past, but their adaptive nature ensures that the birds will survive to see the future. And hopefully, the trees with empty cavities will return once again, giving these birds and the people a chance to adapt to the changing times.