Miniature tracking devices have revealed the epic 30,000km (18,640 miles) migration of the diminutive northern wheatear. The birds, which weigh just 25g (0.8oz), travel from sub-Saharan Africa to their Arctic breeding grounds.

“Scaled for body size,” the scientists report, “this is the one of the longest round-trip migratory journeys of any bird in the world. The team reports its findings in the Royal Society journal Biology Letters.

“Think of something smaller than a robin, but a little larger than a finch raising young in the Arctic tundra and then a few months later foraging for food in Africa for the winter,” said one of the lead researchers, Prof Ryan Norris from the University of Guelph in Ontario, Canada.  The species is of particular interest to scientists, because it has one of the largest ranges of any songbird in the world; with breeding grounds in the eastern Canadian Arctic, across Greenland, Eurasia and into Alaska. Prior to this work though, it was not clear where the birds spent the winter.                            –BBC