New Delhi: As the searing heat of the summer intensifies, bringing life to a standstill in most parts of India, a majestic bird takes off from its wintering grounds in east Africa on a long eastward journey.
For the next few weeks, the pied cuckoo flies a long arc over the Indian Ocean to the west coast of India. On arrival, it spends a few days recuperating from the long and exhausting journey, after which the sleek black and white bird takes off once again. This time it flies over land, spreading out across the subcontinent.
Wherever it goes, the loud metallic calls that it lets out at regular intervals from its perch on a high and exposed branch are greeted with joy. They hold the promise of hope and cooler weather; for in folklore and popular imagination, the arrival of the pied cuckoo heralds the monsoon.
Eagerly awaited: The pied cuckoo. In folklore and popular imagination, the arrival of the sleek black and white bird heralds the monsoon. Clement M. Francis
This association between the rain and the “rain bird” is as widespread as it is old.
In his epic poem Meghaduta, Kalidas draws parallels between the thirst of the pied cuckoo for the rain and the yearning of a pious heart for the divine.
In parts of north India, the bird is known as the “chatak”, or the one that lives on drops of rain. Its black crest is construed as a second beak that points up at the sky, waiting for rain to quench its thirst.
Farmers in Gujarat have christened the pied cuckoo “kharadiyo”, because they believe that its song is louder and more plaintive during kharad, the intermittent dry period between rainy days.
Similar anecdotes are found in Uttar Pradesh and West Bengal, but as interesting as they might be, they don’t qualify as scientific evidence.
Does the bird always arrive before the monsoon? In all parts of the country? How does it know when the monsoon is going to arrive? Couldn’t the relationship between the two be purely coincidental?
There had been no detailed scientific studies, until 2009, when Suhel Quader, a professor of behaviour and evolution at the National Centre for Biological Sciences in Bangalore, created the pied cuckoo campaign.
The campaign might never have happened had the participants of MigrantWatch, a unique citizen science programme that Quader had started in 2007, not been getting bored.
The goal of MigrantWatch was to collate data on migratory birds in India. Amateur birdwatchers could register on the programme’s website and post details of their sightings of migratory bird species, which would be verified, and at the end of the migratory season Quader would collate the data.
This, it was hoped, would over the years lead to a comprehensive database that could be used to analyse migration patterns.
The programme had a successful start, but Quader was soon faced with a problem.
Migratory birds start coming to India in August and leave by April. “So I had this huge group of very enthusiastic birders who had nothing to do in summer,” says Quader laughing.
He was searching for a solution, when it occurred to him that he could use MigrantWatch to verify the longstanding but rumoured relationship between the pied cuckoo and the monsoon.
The bird was an exception on two counts. It was the only bird that migrated from Africa to India; and did so in summer. It had not been included in MigrantWatch because it was not exclusively a migrant visitor; parts of south India did have a resident population.
The pied cuckoo campaign would have to focus on those parts of the country that did not have a resident population. Sightings from these parts would, said Quader, be from the migrant African group that came in around the time of the monsoon. The chances of the southern populations migrating north during the monsoon were low.
The only real evidence, apart from stray sighting records over the years, that Quader could rely on, was a paper by ornithologist Hugh Whistler in the Journal of the Bombay Natural History Society in 1928.
In his paper, Whistler marshalled an impressive collection of sighting records of the bird from across the continent. According to him, all of them pointed to the fact that the bird was an “abundant rains visitor for breeding purposes over a very large portion of India”.
But Whistler was candid about need for more detailed evidence. The records he had collected spanned many decades and were from different parts of the country.
To arrive at any plausible hypothesis, Quader would need to collect yearly sighting data from across the country and correlate it with the arrival of the monsoon in that area.
The motley group of 70 regular birders of MigrantWatch got to work. In 2009, they reported at least 160 sightings from different parts of the country.
The delayed arrival of the monsoon was reflected in the sightings.
Udiyaman Shukla, a 13-year-old school student, joined the campaign in early 2009. He was the first, he claims, to spot the bird in Delhi on 14 July. “It was on one of my regular birding trips to Sanjay Van in the Delhi ridge,” he says. “I spotted the bird five times last season.”
Ahmedabad-based software development consultant Aniket Bhatt, who’s been with MigrantWatch from the beginning, spotted the bird on 13 July. In the 25 years that he’s been birding, he says, the pied cuckoo has always stuck to its monsoon timetable.
The results for the season showed that in most cases the pied cuckoo arrived in an area five to 30 days before the onset of the monsoon.
Quader has an interesting, if slightly speculative, explanation for the very advanced arrivals (those more than 10 days before the monsoon).
The pied cuckoo, he says, is a weak flier. It relies on a low-lying oceanic monsoon jet stream (known as the Somali jet) to help it get across the ocean. In 2009, the monsoon arrived at the Indian coast on time, bringing with it the bird.
The monsoon stalled after that, but since they’d arrived on land the birds moved on, reaching their destinations before the monsoon.
If this theory is true, things become fairly straightforward. The bird knows when the monsoon is coming, because it comes with the monsoon.
It will, however, take a few more years for the pied cuckoo campaign to gather enough data to corroborate the theory.
Some birders, such as expert and author of many bird books, Ranjit Lal, believe that there are other confounding factors that the pied cuckoo campaign needs to take into account.
The cuckoo is parasitic, laying its eggs in the nests of babblers. As luck would have it, babblers also breed during the monsoon, so there isn’t a problem. But even minor shifts in the breeding time of the babbler could, says Lal, affect the cuckoo’s migration.
Despite the doubts, observations so far have shown that across the country the pied cuckoo comes first, and then comes the monsoon.
So the folklore could after all have an element of truth.
This year, the campaign hopes to get many more participants. The enthusiasm is even higher.
Shukla and Bhatt are already on the lookout. As are millions of others who can’t wait for the end of the hottest summer that India has had in the last 100 years.