Imagine travelling 40,000 kilometres using only your body to propel yourself from one point to another. And then imagine travelling another 40,000 kilometres to get back home again. This is what the beautiful Arctic tern does to achieve the longest known migratory route of all bird species. It breeds in Arctic regions, such as Russia and Greenland, before migrating to feeding grounds all the way over in Antarctica. And even across these enormous distances, they manage to find the colonies they were born in, and return to them each year, says the episode of A Week in Science above.

But while the Arctic tern's endurance is very impressive, they do stop for food, water, and rest along the way. The record for the longest non-stop migratory journal for a bird is held by the bar-tailed godwit, which was tracked flying, without a rest, from Alaska to New Zealand, all the way across the Pacific Ocean. "This unbelievable flight was 11,600 kilometres, and took nine days," says RiAus. "It's a bit like a human running at 70 km an hour for a week."

These birds are just incredible. Find out more of them in the latest episode of A Week in Science above.

Source: RiAus