Adam Walleyn leans against the gunwale of the Russian icebreaker and scans the horizon. Lesser twitchers surround him, most about twice his age, binoculars glued to eye-sockets. They point out specks on the horizon. Is that a Wanderer? they say. No, that’s a Southern Royal, Adam replies, briefly raising his binoculars to confirm what he already knows. He is the Justin Beiber of twitching.