Paired on a perch

Razorbills' passing resemblance to penguins is appropriate: They're the last living relatives of another large, land-bound bird. The great auk, once found all over the North Atlantic, was one of the first species to raise ecological concern around overhunting. By the mid-1500s, the bird was gone from European shores, and it went fully extinct by the 1850s. Today, the high-flying razorbill (sometimes called the lesser auk) faces threats of its own such as pollution and habitat destruction. But even as monogamous birds who mate for life, determined razorbill parents keep their species' numbers soaring. Up to 1.6 million razorbills—and counting—currently live in the wild.