“Lost” Canadians surge, testing kids for cholesterol, wearable tech for butterflies, and more

Staff picks: More and more Americans whose ancestors moved from Canada to the U.S. long ago, are trying to get Canadian citizenship. A new law offers them a track to citizenship, no matter how far back their connections go.Also: Kids as young as two should routinely be tested for high cholesterol. Leading doctors say many heart attacks and strokes can be prevented with early detection.And: Monarch butterflies leaving for Canada from Mexico have been fitted with tiny transmitters that can track their long flight in detail. You and your phone can help.Plus: Australia’s social media ban for kids, climate change and fishing gear are trapping humpbacks, World Cup soccer fans can’t afford to stay in Vancouver, and more.