After ten years at sea, postcards sent in a tiny boat to mark 80 years since the evacuation of St Kilda have been found by children in Norway. The miniature wooden schooner was sent to sea to mark the anniversary of the evacuation of the rugged archipelago, 112 miles west of the Scottish mainland.

For 4,000 years, people eked out an existence on the slopes of Hirta, the harbor of St Kilda. But after a pregnant woman died in 1930, the island’s last 36 inhabitants accepted that they had to leave. Ian McHardy, an archaeologist, made the miniature boat to follow an island tradition. People would regularly store mail in tiny craft and launch them in the hope that they would be picked up by passing ships or reach more populated shores.

The archipelago has been in the care of the National Trust for Scotland (NTS) since 1957. The latest boat carried postcards to seven people including NTS patron the Prince of Wales and Norman John Gillies who left St Kilda aged five and died in 2013. It was launched on August 29, 2010.

Almost a decade later, four children found the boat more than 1,000 miles away on the beach of Andoya, the northernmost island in the Vesteralen archipelago in April. Emil Morken, nine, and his siblings were taking their find to their grandfather, Geir Soreng, when they noticed the seven postcards, one of which asked the finder to send them on, which they did. In his letter Mr Soreng said: “My four grandkids found a treasure at the beach on Andoya, North of Norway. It was a postboat in wood, sent from St Kilda in 2010. We had never heard of this fabulous island and are fascinated by the story.”

The card for Mr Gillies was sent to his son John, of Aldham, Suffolk, who said he was delighted to receive it. “For a postcard that has been in the water for ten years it’s in remarkably good condition,” he said. “My dad would have been really chuffed.” Mr Gillies said that he had a family connection to the mailboats. His great grand-uncle, Alexander Gillies Ferguson, was reputed to have started the tradition when he put letters in a watertight bag inside a tiny boat.

Technology that can scan the unique stripes of zebras or the notches on a whale’s tail like a bar code is being used to track some of Africa’s most endangered species.

A census of the dwindling Grevy’s zebra, during which researchers spent painstaking weeks comparing photographs, is now being done in the blink of an eye. Visitors to parks in northern Kenya, home to 95 percent of the Grevy’s population, are being asked to submit pictures of animals they spot. These are scanned by the Image Based Ecological Information System (Ibeis). The technology has also been used to count the unique spot patterns on the bellies of manta rays, the fur patterns of polar bears and notches on the tails of whales. With the help of algorithms similar to those used in facial recognition the software identifies each animal’s unique marking “hot spots” to determine whether an animal has previously been recorded.

An accurate estimate of the number of individual animals in a population is key to determining the health of the population and the species’ conservation status. Ibeis, which was developed at Princeton University, Rensselaer Polytechnic Institute, the University of Illinois and the non-profit organization Wild Me, is far less invasive than tagging.

Grevy’s zebras, the largest of the three zebra species, once roamed five African countries but are now only found in northern Kenya and pockets of Ethiopia. There are estimated to be fewer than 3,000 in the wild.