Artificial nests like this one have helped the African Penguins recover from destruction of nesting grounds. Similar tactics are in use in Peru. Photo courtesy of St. Louis Zoo.

African Penguins in their nests on Dyer Island off the coast of South Africa. Photo courtesy of St. Louis Zoo.

The unrestricted harvest of guano in South Africa left penguins and other seabirds without adequate nesting grounds and consequently in danger of extinction. Photo courtesy of St. Louis Zoo.

Workers pose with packaged guano ready to be sold for fertilizer to area farmers after the 2007 harvest. Photo courtesy of St. Louis Zoo.

This scene from 2007 will be repeated every day for several weeks while the new guano harvest continues. Photo courtesy of St. Louis Zoo.

Yellow tape marks the line that workers cannot cross during harvesting.