A small migratory bird, named B6, has performed one of the most extraordinary endurance feats known in the natural world.The Bar-tailed godwit, a shorebird weighing only a few hundred grams, has stunned scientists by completing a non-stop flight of around 13,560 kilometres across the ocean, travelling from Alaska to Tasmania.This four-month-old bar-tailed godwit covered the distance in just 11 days back in 2022, setting a record for the longest non-stop flight by any animal.Tracked by a satellite tag from the US Geological Survey (USGS), B6’s trip highlights the wonders of bird migration.Breeding across Arctic regions of Alaska and Siberia, the bird undertakes a biannual journey to its wintering grounds in New Zealand and Australia.The Alaska-to-New Zealand route spans approximately 11,000 kilometres, completed in roughly nine days without resting, eating, or drinking.Flying continuously over the open Pacific Ocean, godwits navigate using celestial cues, magnetic fields, and an internal compass of astonishing precision.Tracked individuals have sustained speeds exceeding 55 kmph, making the bar-tailed godwit an unrivalled migratory species of bird.Navigation is key during such flights, especially over endless water.B6 used Earth’s magnetic field as a natural compass. Special proteins in its eyes, called cryptochromes, detected these fields, guiding it straight to Tasmania.This built-in GPS in birds’ brains turns on during migratory flights to help guide them to their destination. Studies have shown birds also use stars, the position of the Sun, and even smells to navigate. But for long ocean crossings, magnetic sensing is crucial.B6 also didn’t land for 11 days, but it rested in the air using what is called unihemispheric sleep. That is the process where one half of the brain sleeps while the other stays alert to keep flying. It’s like napping with one eye open.The research has been led by migration scientists including Phil Battley and Jesse Conklin, whose teams have spent years tagging and monitoring these birds to understand their extreme journeys.The record-breaking flight has drawn global attention to the astonishing endurance and navigational abilities of migratory birds.