Ben Goldfarb

This article originally appeared in longer form in bioGraphic.
Every spring, as the daylight lengthens and the weather warms, rivers of birds flow north across the Midwest. They fly high and at night, navigating via the stars and their own internal compasses: kinglets and creepers, woodpeckers and warblers, sparrows and shrikes.They come from as far as Central America, bound for Minnesotan wetlands, Canadian boreal forests, and Arctic tundra.

Spring is a bloody season on American roads. Yearling black bears blunder over the asphalt in search of their own territories. In the West, herds of deer, elk, and pronghorn scamper across highways as they migrate from winter pastures to summer redoubts.