We do not know Flappy McFlapperson's age. But we do know that she is an adult. And that she weighed a mere 119 grams — slightly more than a bar of Toblerone chocolate but lighter than your smartphone — when she was caught to be fitted with a 4.5-gram tag. Every now and then, it is this tag that gives Terry Townshend and his collaborators the heebie jeebies. An absence of signal for several days indicates that something is amiss, or in the worst case scenario, that the bird is dead.
"It can be an emotional roller-coaster. Sometimes, we become anxious if we haven't received a signal for several days. When we finally receive one, there is relief," admits Townshend, a British conservationist, birder and a Beijinger for the last seven years.
"There is also elation when we see that one of the birds has navigated the incredible Arabian Sea, crossing safely." Flappy is "one of the birds" — the sole survivor of five common cuckoos (Cuculus canorus) tagged and released from Cuihu Wetland Park, roughly 38km northwest of Beijing, in May 2016. The birds were tagged in an attempt to discover "for the first time where the cuckoos from East Asia spend the winter" as well as to get people, especially children, to engage with avian life. The Beijing Cuckoo Project tagged three more cuckoos earlier this year, but given that their 2-gram tags were smaller, Townshend believes that "the very small solar panels are being shaded by the birds' feathers, so the battery is not charging and thus we're not receiving any signals".
This brings us to Flappy, whose tag has sprung to life each time there's been a lull since she was tagged last summer. Even as you read this, she is flapping about the semi-arid region of eastern Kenya in Africa, having flown thousands of kilometres, crossing the Arabian Sea without a hold or a perch from India. "Flappy is in Africa!! She's crossed the Arabian Sea and is now in Ethiopia, having flown another 650km since making landfall in Somalia. That's more than 3,300km non-stop from India. What a bird," Townshend documented on Flappy's blog on 22 October 2017.
This is the third time he and his collaborators, including scientist Chris Hewson of the British Trust for Ornithology and other partner organisations, have recorded Flappy's long-haul over the Sea. The first time she did so was in November 2016. In three days, from November 1-4, she flew more than 2,000km non-stop from central India to an island off the coast of Oman, and continued the journey south to Somalia. The Beijing Cuckoo Project team was euphoric. "It's another phenomenal journey… more than 2,000km non-stop from her previous position in central northern India. Go Flappy!" they documented on the blog. By 11 November, they'd recorded Flappy's "13th border crossing involving 11 countries since she was tagged in May 2016 (China – Mongolia – China – Myanmar – India – Bangladesh – India – Nepal – India – Pakistan – Oman – Yemen – Somalia – Ethiopia)."
Flappy's second crossing over the blue Arabian expanse came in May this year as she returned to her breeding ground in northern Mongolia. She stunned the team by her near non-stop flight, going north from Somalia into Oman, Pakistan, crossing the Thar desert en route to Uttar Pradesh in India, and then turning southeast to Myanmar — all in just four days from May 11-15. "OK, I am lost for words. Flappy is clearly a machine. She has just flown another 2,000km from northern India to Myanmar. That's 6,500km in 6 days," read the May 15, 2017 blog post.
Even as her return sojourn (along with that of two other tagged cuckoos) solved the mystery of the East Asia cuckoos' wintering grounds (central African nations), Townshend says the public outpouring has been beyond expectation. "I'm overwhelmed by the success. We now know where the cuckoos spend the winter and how they get there. And the media reaction in China and overseas has meant that we have reached millions of people, most of whom wouldn't ordinarily read anything about birds." The outpouring was no doubt spurred by the team's decision to open the project to the public. "We've deliberately involved ordinary people from the start — from catching the cuckoos, fitting the tags, naming the birds, following them via a website/social media — and so these people have been part of the scientific discovery," says Townshend.
BIRDS OF A FEATHER...
... don't always fly together or even migrate. Indeed, many cuckoo species stay where they are all year round, says Indian conservationist Suhel Quader of the Nature Conservation Foundation. "This is particularly true of many tropical cuckoos, including several Indian cuckoos like the koel (Eudynamys scolopaceus) and the common hawk cuckoo (Hierococcyx varius). Cuckoos of temperate regions that get very cold in the winter, are more likely to migrate, including the common cuckoos of China and Europe," says Quader.
Even among the cuckoo species that do migrate, the birds go solo, unlike other small birds such as Amur falcons (Falco amurensis). "As far as we know, cuckoos usually make these flights alone. There are a few records of small groups flying together but we believe the majority fly solo," says Townshend. "This is even more remarkable for cuckoos when one considers that the young birds have never even met their parents (because cuckoos practice nest parasitism i.e. they leave their eggs in the nests of other bird species to be hatched). So they make the journey completely by instinct and are not taught."
This would imply that the winter migration for common cuckoos from East Asia is an expedition that is entirely self-taught — one on which there are many perils. "Starvation is a clear threat. If migrating birds can't feed enough to build up fat reserves for migration, particularly before a long, non-stop flight, such as has to be made when crossing the Arabian Sea, then they are in deep trouble," says Quader. "The other main risk is predation, as raptors are always on the lookout for weak and vulnerable migrating birds. Some birds are hunted during their migration, but I don't think common cuckoos are among them."
He points out another incredible aspect from Flappy's journey. "I had thought that birds fly more or less directly to their destination, except for stopovers to refuel," he says. "So the most striking thing is how non-direct Flappy's route was. In India, in particular, she wandered around, sometimes backtracking great distances, before crossing over the Arabian Sea in one great leap."
WELL BEGUN IS HALF DONE
So how does a small, lightweight bird undertake a journey it has never been chaperoned on before? Does it fly by day or at night?
Does it look for signs while soaring or go with the wind? And how does it manage to cross an enormous expanse of water over a sustained period with no food and no perch?
"The truth is we are not 100 per cent sure," says Townshend. "We know that some birds navigate using the stars and others use the Earth's magnetic fields... but for cuckoos, we're not sure. It may be a combination of magnetic fields, stars and visual landmarks."
He explains that cuckoos tend to follow the rains, and that in late autumn and winter, the rains move south along the east African coast, brought in by the seasonal easterly winds from the Arabian Sea. "They (cuckoos) don't particularly like to be rained on, but they like places that have received recent rainfall, so they gradually follow the rains in eastern Africa."
Quader, who has studied the connection between the Southwest monsoon and the pied cuckoos (Clamator jacobinus) in India, endorses Townshend when he says that the birds exploit prevalent winds — what we call the 'retreating' monsoon in India — to help them make the long journey across the Arabian Sea. These rain clouds are crucial to their journey because cuckoos prefer to feed on soft-bodied invertebrates such as caterpillars, which tend to emerge after rain.
Food and good habitat, such as forests and open woodlands, remain critical factors throughout the cuckoos' migration. Many birds, says Townshend, will lose at least half of their body weight during migration, so they need to build up fat reserves ahead of any long flight. "Flappy would have needed to fatten up and gain weight by eating lots of 'power food' — in her case juicy caterpillars," he adds. "And when they arrive at their destination, often a so-called 'stopover site' on the way, they will feed, drink and rest before beginning the next leg of their journey."
The next leg for Flappy is a few months away. It's likely she'll be flying in and out of the borders of Mozambique and Tanzania as she did last year before embarking on a swift journey back to her breeding ground on the border of Mongolia and Russia sometime in February or March 2018. Yet, the Beijing Cuckoo Project team spends each day anxiously waiting to pick up a signal from her tag, for each signal holds tiny clues to several questions. As Townshend puts it: "The project has reinforced my fascination with the natural world, especially migratory birds. The truth is we know so little about nature's secrets."
A CUCKOO'S CALL
- Flappy McFlapperson, a common cuckoo, was caught in a special net at the Cuihu Wetland Park, Beijing, China, in May 2016. A tag, which includes a transmitter, a battery and a solar panel, was fitted on her nape. The solar panel charges the battery, which in turn, powers the transmitter.
- The transmitter regularly sends out signals that are picked by satellites orbiting the Earth. The satellites transmit the data to a ground station. Using special software, researchers for the Beijing Cuckoo Project calculate the location from which the signal was sent, allowing them to know her location in near real time.
- The data that the researchers get depends on the signal from the transmitted, and there've been days when there's been no signal from Flappy's tag. This, says Terry Townshend, can be for several reasons. The most common reason for this is when the battery isn't charged, which happens when the weather is poor or the bird is feeding on the forest floor, due to which the sunlight doesn't reach the solar panel.
- A lack of signal may also be due to a technical failure, although this is rare. Or if the tag falls off the bird and lands in a spot where it doesn't receive any sunlight. This too is rare.
- Finally, there won't be a signal if the bird is dead. "We often know if this is the case because the transmission from the signal includes data about temperature," says Townshend. "If the bird is healthy, the temperature fluctuation between day and night is relatively small as the bird's body temperature keeps the tag at a relatively constant temperature. If the signal shows the tag temperature is fluctuating significantly between day and night, it means the bird's body temperature is not regulating the tag's temperature, suggesting that either it has fallen off or the bird is dead."
(You can follow Flappy McFlapperson's journey on https://birdingbeijing.com/flappy-mcflapperson/)