Despite what can feel like Arctic weather sweeping into Iowa during the winter, the state still finds itself a long way from the Arctic tundra.

But since early November, reports of an iconic tundra-dwelling bird, the snowy owl, have been pouring in from all corners of the state.

Wildlife biologists call the phenomenon a “winter irruption,” and it has already yielded numerous sightings of this all-white, vulture-sized owl in Iowa...