Let the moose-spotting begin. As thousands of Swedish moose begin their annual migration for the summer, moose aficionados and casual fans from across the globe are tuning in to witness the journey.

Before Swedish slow TV hit “The Great Moose Migration” began airing Tuesday, Ulla Malmgren stocked up on coffee and prepared meals so she doesn’t miss a moment of the 20-day, 24-hour event. “Sleep?

In an ever more frantic world, it transpires there is a vast audience for moose meandering across the wilderness. Since 2019, The Great Moose Migration (in Swedish, Den stora älgvandringen) has used ...