A Heermann's Gull (Larus heermanni) on a buoy near Isla Rasa, a small island in Mexico's Sea of Cortez (Gulf of California) in 1992. The small flat island, which gives it the Spanish name (Isla Rasa), is home to almost all the Heermann's Gulls and Elegant Terns in the world when they go there to breed. The Heermann's Gulls from as far away as British Columbia and the Elegant Terns from Peru and Chile. Mexican Biologist Enriqueta Velarde has studied the birds on the island for years, and claims to see a direct result of overfishing just from what they eat. As the populations of sardine were over exploited by fishing, the birds were bringing back more and more anchovy - a fish with less nutritional value. Thanks to her efforts the species are now officially protected by Mexican law and populations have rebounded. (Australfoto/Douglas Engle)

A Heermann's Gull (Larus heermanni) on a buoy near Isla Rasa, a small island in Mexico's Sea of Cortez (Gulf of California) in 1992. The small flat island, which gives it the Spanish name (Isla Rasa), is home to almost all the Heermann's Gulls and Elegant Terns in the world when they go there to breed. The Heermann's Gulls from as far away as British Columbia and the Elegant Terns from Peru and Chile. Mexican Biologist Enriqueta Velarde has studied the birds on the island for years, and claims to see a direct result of overfishing just from what they eat. As the populations of sardine were over exploited by fishing, the birds were bringing back more and more anchovy - a fish with less nutritional value. Thanks to her efforts the species are now officially protected by Mexican law and populations have rebounded. (Australfoto/Douglas Engle)