O n a crisp bright early spring afternoon on a small uninhabited island in the Ångerman river in northern Sweden , the stars of The Great Moose Migration are proving suitably elusive. Just as they do, for the most part, to viewers of the world’s biggest slow TV phenomenon – a three-week-long, 450-hour, free-to-view continuous livestream from the Västernorrland wilderness that has a global audience of millions mysteriously captivated every year, despite precious little happening at all. Hardcore watchers will be lucky to spot an älg , as they are called in Swedish, making their annual crossing of the Ångerman en route to richer summer pastures north any more frequently on average than about once every 400 minutes. But among this landscape, which moose have traversed for 6,000 years, traces of the illustrious beasts are everywhere if you know where to look for them.…