It was one of the mightiest birds ever to walk on Scotland’s shores, but was hunted to extinction more than a century ago.

The Great Auk stood three feet tall and lived like a penguin – shuffling on land but at home in the water.  

Prized for its meat and feathers, the bird was decimated by sailors who cur down whole flocks they had herded onto their boats – and even used its carcass for fuel on treeless islands.

All that remains of the once mighty species are a few specimens in jars and stuffed carcasses – but the Great Auk is still teaching scientists about the mysteries of its life cycle and how it can be observed in other birds.

A new study using the long-vanished bird is helping to build a picture of how seabirds survive the lean winter months and how manay calories they need at different times of the year.

The study, which comes as seabird populations decline across the UK, could help preserve populations by unlocking the mysteries of their dietary needs during the lean winter months when they are at sea.

The research was carried out by Dr Ruth Dunn, a seabird ecologist at Lyell Centre - an earth and marine sciences centre based at Heriot-Watt University in Edinburgh.

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Dr Dunn has developed a new framework that scientists can use to work out how much energy a given seabird needs at any time of year, whether penguins, gulls, ducks or guillemots.

She said: “Just as the average human needs around 2000 calories a day to function, seabirds also have an optimum calorie consumption.

“The lives of seabirds during winter are a bit of a mystery, as they’re out of sight for months at a time. But we know that during this time North Atlantic species often dive more, they’re colder and they’re facing increasingly stormy weather - those all require more calories.” 

Dr Dunn’s method of calculating any seabird’s intake relies on various factors. Bigger birds need more energy, but lifestyle factors also have an impact.  

She said: “We split seabirds into nine lifestyle categories based on their behaviours and what we call ‘ecological guilds’. Do they migrate over long distances, or stick close to the coast? Do they flap or glide while flying? Do they propel themselves underwater with their feet or wings? 

“Our framework is a series of equations based on all these physical and behavioural factors.”

Dr Dunn and her colleagues tested the framework on the Great Auk precisely because it’s extinct -  all that remains are a few records and some museum specimens.

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The bird expert said: “Using the Great Auk demonstrates the ability of our framework to give insights about even the most data-deficient species. 

“We did know enough to get started. They had small wings, so we don’t think that they flew but they were very efficient divers. They’re also similar to razorbills and guillemots, so we made some inferences based on that.

“We imagined three possible migration scenarios for the Great Auk. The first is that it lived in one place, say Iceland, fished there and stayed put throughout the year - similar to guillemots in Scotland.

“Or it could have been more like a sub-Antarctic gentoo penguin, foraging during the day and returning to the land at night.

“The third scenario is based on the fact that Great Auk bones have been found in Morocco - it may have swum all the way there from Iceland to spend the whole summer in warmer waters.”

Dr Dunn added: “We found that its daily intake would have been between 2485 and 1700 calories, depending on its migration activity. That’s equivalent to 49 and 36 sandeels, a major food source for seabirds.

“It might seem strange to test our framework on an extinct seabird, but it demonstrated its capabilities. Hopefully, this will capture the imagination of other seabird researchers and push them towards more breakthroughs.”

The Herald: The rerearch is helping scientists understand seabirds 

Great Auks ranged over much of the north Atlantic for thousands of years and could be found nesting in crags and cliffs from America to Europe. 

One Great Auk bone dating from the fifth century was uncovered near the Scottish Seabird Centre in North Berwick, indicating they were also eaten by medieval Scots. 

However, they were hunted relentlessly in the 18th and 19th century as European ships spread out across the globe, with sailors using them as living larders they could pack on to boats.  

Hunters were advised to strip the birds’ feathers while they were still alive, before leaving them to perish from the elements. 

Britain banned the killing of the bird in 1794, except by fishermen. But by then it was too late. 

The final great auk found in the British Isles is said to have been taken on a sea stack off of St Kilda, by fishermen hunting gannets.

Dr Dunn said: “Seabirds are critical marine predators. They consume millions of fish to fulfil their energy requirements.

“Understanding their dietary requirements will help us understand their effect on the marine environment.

“That’s especially important when so many of them are in decline, and the seas and planet are undergoing huge changes."