By Sophie Hardach

White storks are breeding again in Britain, helped by a rewilding project

(Credit: Knepp Estate)

Helped by a bold rewilding project, storks are migrating between Britain and North Africa again for the first time in 600 years. How can we make their journey safer?

It is a cool morning in March and I am wading along a muddy path, part of the vast, ancestral grounds of Knepp Castle in southern England. The scenery looks ancient and dramatic, a patchwork of well-trodden grass, deep puddles and tangled scrubs, studded with majestic, bare-branched oak trees. High up in the crowns of the trees are huge storks' nests the size of tractor wheels, their dark silhouettes contrasting with the pale blue sky. White storks glide through the sky and land in the nests, while others sit and warm their eggs. Every now and then, the air is pierced by a joyful clattering sound as they greet each other.

"We sometimes describe this as stork headquarters," says biologist Laura Vaughan-Hirsch, gesturing at the nests around us. She leads the White Stork Project at Knepp Estate, which started in 2016 and is part of a wider stork reintroduction project in southern England. As we talk, a stork in one of the highest nests climbs on top of another: "They're mating," says Vaughan-Hirsch. A short while later, a clattering sound is heard from the nest, which is, she explains "all part of the bonding".

"The first time I saw them here, it was a bit like Jurassic Park (the movie) really, the way they were flying over your head," says Amy Hurn, a volunteer who has been helping monitor the birds for two years. "I had never seen a white stork in the wild before, I never knew that that was near to where I live."

Since 2019, the younger birds have started migrating – adding a whole new dimension to the project. A number have been equipped with trackers, allowing the team to trace their epic journeys. Their travels are connecting Knepp Castle with storks' wintering sites as far as Spain, Portugal and Morocco. But in the process, new hazards to the rebounding population have emerged, including collisions with power lines.

This poses another challenge for those keen to protect England's new stork community: how do you go from providing suitable nesting sites, to helping the birds travel safely and find supportive habitats across a whole continent?

Storks generally try to choose the shortest route across water, research suggests, since they can't use their usual soaring flight strategy there as thermal updrafts over water tend to be weaker than on land. They therefore need to flap their wings to cross water, instead of just gliding. As this is tiring, they look for the shortest crossing – and the tracking lines indeed show most of them choosing the shortest stretch of water, between Dover in England and Calais in France, Franco points out.

There are some exceptions, however; one stork ended up on a fishing vessel in Cornwall and used it to travel to the west coast of France.

Once they reached the other side, the storks appeared to instinctively use a tactic common among young wild storks: follow more experienced wild storks. As young storks join the flocks along the way, the travelling flocks can swell to hundreds of storks all flying and circling up the thermals together, in one of nature's great spectacles.

Source: adapted from <https://www.bbc.com/future/article/20240326-how-an-english-castles-grounds-became-a-stork-paradise>

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