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Cuckoo’s calling

A nine-year-old boy writes excitedly in his diary: ‘Cuckoo calling, first of the summer!’

Today, decades later, he still feels the same thrill when he hears that distinctive ‘wandering voice’. In fact, Professor Nick Davies FRS has spent the last thirty years studying cuckoos and has just published a new book entitled Cuckoo: Cheating by Nature.

I first meet him at a book launch for another Pembroke Fellow, where he tells me, ‘I’m always amazed by these kinds of events. I look around at all the fantastic books that my colleagues have managed to produce and think: I’m just a guy who likes looking at birds.’ This is a typical example of his modesty. Despite the fact that David Attenborough has called him ‘one of the country’s greatest field naturalists’, Nick is insistent that he is just a bird watcher who was lucky enough to make his ‘obsession’ into a career.

493746-largeNick’s love affair started when he was six year old and would feed the birds in his parents back garden. During his teenage years he began to read books like Lack’s The Life of the Robin and Tinbergen’s The Herring Gull’s World, which gave him a ‘bird’s eye view’ of the world. He came up to Pembroke in 1970 to study Natural Sciences and was told by his tutor: ‘The days when you can go out into the countryside with binoculars and notebooks and discover something interesting are long gone.’ Nick refused to believe it.

His weekends were spent cycling to Wicken Fen, Britain’s oldest nature reserve, to tag the birds and observe their behaviour. After graduating, he spent six years living in a hut in the woods near Oxford before returning to Pembroke in 1979 to study the sex life of hedge sparrows at the Botanic Gardens.

He published his first paper about the harbinger of spring, the cuckoo, in 1987. It was the start of an enduring fascination with their notoriously outrageous behaviour. Since the time of Aristotle, cuckoos have been known as cheats. Chaucer, Shakespeare and Milton all referred to their wily ways; not for nothing has the word cuckoldry entered the English language as a synonym for adultery. Ted Hughes, another Pembroke man, understood the danger implicit in the initial cuckoo call of summer: ‘That first ribald whoop, as a stolen kiss / Sets the diary trembling.’

This sense of fear, and in turn the underlying puzzle of the cuckoo, lies in the way that the birds treat their young. They seem to lack maternal affection – long considered by scientists to be one of the first dictates of nature. Before laying her egg, a mother cuckoo locates the nest of another bird. She throws out one of the eggs and then quickly lays a matching egg in its place. She then abandons it to be raised by the host’s owner. In this video, Nick helps David Attenborough to observe the dastardly deed in action:

Once the cuckoo chick hatches, it pushes all of the other eggs and chicks out of the nest. The host bird then finds itself feeding and caring for the cuckoo chick, even when it has grown far larger than the host bird itself. This absurd image has captured the imaginations of generations of birdwatchers and scientists.

feedingPicture: David Kjaer / Solent

Nick has studied almost every part of this process of deception. How does the cuckoo select a host nest? What if the host bird sees her at the nest? How does she get her egg to match? Does the speed at which she lays her egg matter? Why don’t host birds spot the imposter egg? How does the baby chick know to eject the other eggs? How is the host bird tricked into feeding the cuckoo chick? What defences do hosts co-evolve to avoid the cuckoo’s ruse? Each stage is detailed in his new book, which provides a readable overview of the forty plus scientific papers that Nick has published on the subject.

Cuckoo is also a history of the different ways that scientists have approached the cuckoo conundrum and a record of changing human perceptions of the natural world. From the sixteenth-century naturalist William Turner, a former Pembroke Fellow who Nick feels ‘peering over my shoulder’ as he writes, to Leigh Van Valen, author of the ‘Red Queen’ hypothesis of evolution, this is a story of human understanding being continually thwarted by the ingenuity of birds.

In the later chapters Nick talks about his own work to trick the cuckoo into revealing its secrets using model eggs, taxidermy mounts of birds and radio transmitters. This is cutting-edge science relayed as a charming story of long bike rides in the Cambridgeshire countryside, bootfuls of mud and encounters with confused policemen.

image_normalDespite his comprehensive and detailed work on the cuckoo, Nick’s book is littered with phrases like ‘further studies are needed’ and ‘it would be fun to do the experiment’. Clearly he is far from bored with his outdoor lab in Wicken Fen. Perhaps unusually for an academic, he is more likely to be found in the mud clutching a stick and his binoculars than sat at a desk writing grant proposals. ‘One could spend a lifetime here,’ he writes, ‘just sitting on this bank, and still always be discovering something new.’

Nick has become so embedded in the wild landscape of the fens, and so intensely familiar with the ways of the creatures that he watches, he lapses into sentences that start: ‘I often think that if I was a bird…’ He talks about the need for him and his colleagues to ‘play cuckoo’, to ‘become cuckoos ourselves’ and, in one interview with Cambridge News, he confessed: ‘I’ve always wanted to be a bird’.

The thing that troubles him most is that this love of nature seems to be lacking in younger generations. ‘When I go birdwatching at the weekends I look around and it is just other old guys like me,’ he jokes, ‘All the young people are at home watching David Attenborough documentaries on their computers.’

He is desperately concerned about the lack of literacy in natural history among the students he teaches: ‘I recently met one of my students at the end of a day in the field and she asked if it had been a good day. I told her that I hadn’t managed to get any data but that it had been a fantastic day watching the birds. She just couldn’t understand what I meant. But for me the birds have always been the most important thing.’

This enthusiasm spills out of him like a teenager in the first flush of love. ‘Can I just tell you about the signatures on their eggs?’ he asks, ‘Do you mind?’ It is the same excitement that leads him to stop tourists in the Botanic Gardens to give them an impromptu lecture on orchid evolution or to encourage his non-scientist colleagues to sit in a hide in the pouring rain to see the birds raise their beaks defiantly at the storm. In fact, after all this time, it is the same impulse that led him – as a nine year old boy – to celebrate the arrival of summer’s first cuckoo call with an exuberant, hope-filled ‘!’

cuckooIf you want to find more about Nick’s research, free tickets are available for the 2015 Royal Society Croonian Lecture on Thursday 14th May, when he will give a lecture entitled ‘Cuckoos and their victims: An evolutionary arms race’.

Alternatively, you can listen to him presenting a 30 minute programme about the cuckoo on BBC Radio 4 through the iPlayer website.

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