Hope is a thing with feathers

Birds are all around us. They appear and disappear; they go between worlds as we never can.

Across history, birds have bewitched poets and scientists alike. Photograph: Ruggero Maramotti/Gallery Stock

We read so much into birds. The canary down the mine whose death warns miners of gas and the dove with a green twig that tells Noah the flood is receding feed into a feeling that birds are sign-bearers, omens, the gods’ messengers. Across history, across cultures, birds are also an image of escape. “Oh, for the wings of a dove,” says King David, so he could fly to the wilderness and be at rest.

Birds spell renewal. Children in ancient Greece welcomed the swallow as a messenger of spring. “Hope,” Emily Dickinson writes, “is the thing with feathers/That perches in the soul” – and when I hear a wren singing in the freezing cold of the early morning (how can something so small fill the backstreets of Kentish Town?), my heart does something that approximates to lifting.

But all this is just our imagination, as we plunder nature for symbols. In biological reality, birds are even more extraordinary. They are evolved creatures, programmed by their DNA, adapted to a particular place or trajectory, which fulfil the destiny written in their genes through behaviour that bewitches poets and scientists alike.

I spent Christmas and New Year in Assam, India. In the grasslands, I was thrilled to see a rare Asian otter climb out of the river among grazing rhinos and stand up like a periscope to look over reeds. On Christmas Day, I saw a tiger stalking deer. On New Year’s Day, I watched the red sun rise through strata of blue mist from an elephant’s back.

All of that was wonderful but, for me, one of the most exciting things was seeing bar-headed geese graze among wild buffalos. Their migration, a story of fortitude, risk and adaptation, demonstrates how ancient birds are. Their migration routes record the shift in the planet’s tectonic plates. Bar-headed geese nest in central Asia but they winter on the other side of the Himalayas and cross Everest to get there. The oxygen a bird needs to keep flying is 20 times what it needs at rest. The air over Everest has a quarter of the oxygen available at sea level. The haemoglobin of these geese absorbs oxygen faster than most other birds’ and their capillaries penetrate deep into the muscle, so the oxygen reaches further and they get more from each breath. The geese evolved like this because they and their route are older than the Himalayas. As rocks rose across their path, they didn’t look for a new route – they just changed their haemoglobin and went where their DNA said.

Birds are all around us. They appear and disappear; they go between worlds as we never can. They speak to us of distance, other countries, other ways of being. The medieval alchemists had a mystical language of birds which translated what was divine and of the air into the base earth of humanity. That’s why, curating this summer’s new writers’ talks at ZSL London Zoo, I picked the tropical bird house. Each writer will read a specially commissioned piece on an endangered animal in that animal’s presence, alongside one of ZSL’s conservationists. Helen Dunmore will take the Sumatran tiger; Glyn Maxwell has the Majorcan midwife toad; Mark Haddon has the Galapagos tortoise. Jo Shapcott began on 14 May with the slender loris and Andrew O’Hagan ends the series with Malaysian tapirs. I’m concentrating on bleedingheart doves, whose homes in the Philippines are vanishing as forests are cut down.

One of the main roles of the zoo is to fund conservation projects carried out across the globe by the Zoological Society, supported by research from its Institute of Zoology. This conservation work is the envy of the world but also, surprisingly, one of London’s best-kept secrets.

Today, the wren singing in my garden is doing its bird thing, giving me hope as I write – hope that these writers’ talks will light a few candles for urgent conservation.

For details of the writers’ talks at ZSL London Zoo, visit: zsl.org. Ruth Padel’s book on migration, “The Mara Crossing”, is published by Chatto & Windus (£14.99)