New Scientist reported on a paper by biology professor emeritus Bernd Heinrich on why flocks of redpoll birds burrow in the snow, creating a maze of tunnels. “Spending the night in snow tunnels may help them survive the freezing nights in the Arctic tundra, even though it would also make them vulnerable to burrowing predators, such as short tailed shrew, and could potentially leave them in an ice tomb,” Heinrich concludes. Read this story.