Two peregrine falcon chicks huddle in their cliff nest, along the Colville River in Alaska. This bird is one of the most widely distributed species in the world, found on every continent except Antarctica. Historically, the use of DDT as a pesticide resulted in a rapid decline in their population, but since the ban on DDT use in the U.S. took hold in the 1970s, peregrine populations have recovered significantly.
Joel Sartore
