Tui De Roy / Brown pelican (Pelecanus occidentalis) in flight above wave. San Cristobal Island, Galapagos, Ecuador, June.

Kevin Schafer / Marine Iguana (Amblyrhynchus cristatus) walking on sand, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Yellow warbler (Dendroica petechia) female in shoreline manzanillo tree just after bathing in sea water, Playa Ochoa, San Cristobal Island, Galapagos Islands, Ecuador, June.

Tui De Roy / San Cristobal lava lizard (Microlophus bivittatus), San Cristobal island, Galapagos, South America

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki) mother and pup resting on volcanic beach. Endangered. San Cristobal Island, Galapagos, Ecuador, June.

Tui De Roy / Galapagos sea lions (Zalophus wollebaeki) resting on volcanic beach. Endangered. San Cristobal Island, Galapagos, Ecuador, June.

Tui De Roy / Galapagos sea lion (Zalophus wollebaeki). Endangered. San Cristobal Island, Galapagos, Ecuador, June.

Tui De Roy / Brown pelican (Pelecanus occidentalis) diving. San Cristobal Island, Galapagos, Ecuador, June.

Tui De Roy / Brown pelican (Pelecanus occidentalis) in flight against dusky sky. San Cristobal Island, Galapagos, Ecuador, June.

Tui De Roy / Brown pelican (Pelecanus occidentalis) dipping head to catch fish. San Cristobal Island, Galapagos, Ecuador, June.

Pete Oxford / Galapagos Sea Lion (Zalophus wollebaeki) and tourist boats in the harbor, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / San Cristobal Mockingbird (Nesomimus melanotis), San Cristobal Island, Galapagos Islands, Ecuador

Pete Oxford / Marine iguana (Amblyrhyncus cristatus) tracks in the sand. Cerro Brujo, San Cristobal Island. GALAPAGOS

Pete Oxford / Human footprints in the sand. Cerro Brujo, San Cristóbal Island. GALAPAGOS

Pete Oxford / Marine iguana (Amblyrhyncus cristatus) tracks in the sand. Cerro Brujo, San Cristobal Island. GALAPAGOS

Pete Oxford / Coastal landscape, Cerro Brujo, San Cristóbal Island. GALAPAGOS 2006

Pete Oxford / Beach. Cerro Brujo, San Cristóbal Island. GALAPAGOS 2006

Pete Oxford / Silhouette of Blue-footed Booby (Sula nebouxii excisa) flying, San Cristobal Island, Galapagos

Pete Oxford / American oystercatcher (Haematopus palliatus) Cerro Brujo, San Cristóbal Island. GALAPAGOS

Pete Oxford / Silhouette of Blue-footed Booby (Sula nebouxii excisa) flying, San Cristobal Island, Galapagos

Pete Oxford / Human footprints in the sand. Cerro Brujo, San Cristóbal Island. GALAPAGOS

Pete Oxford / Blue-footed Booby (Sula nebouxii excisa) at nest with eggs, San Cristobal Island, Galapagos

Pete Oxford / Human footprints in the sand. Cerro Brujo, San Cristobal Island. GALAPAGOS

Pete Oxford / Beach, Cerro Brujo, San Cristobal Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Sea Lion (Zalophus wollebaeki) pup and tourist, Cerro Brujo, San Cristobal Island, Galapagos Islands, Ecuador

Pete Oxford / Galapagos Sea Lion (Zalophus wollebaeki) sunning, watched by tourist, Cerro Brujo, San Cristobal Island, Galapagos Islands, Ecuador

Pete Oxford / Magnificent frigatebird {Fregata magnificens} attacking booby, San Cristobal Island.

Mark Moffett / Aerial view of the coast showing finger rock on the background, San Cristobal Island, Galapagos Islands, Ecuador

Mark Moffett / Aerial view of tree-covered crater, San Cristobal Island, Galapagos Islands, Ecuador

Mark Moffett / Aerial view of craterized district, San Cristobal Island, Galapagos Islands, Ecuador

Mark Moffett / Galapagos Giant Tortoise (Chelonoidis nigra) feeding on grass that has already been eaten back to stubble, San Cristobal Island, Galapagos Islands, Ecuador

Mark Moffett / Galapagos Giant Tortoise (Chelonoidis nigra) pair mating, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Galapagos sunset with Kicker Rock, an old eroded tufa cone, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Kicker Rock, an old eroded tufa formation with tour vessel, near San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Old tuff cone formation deeply eroded by rain and time, some of the oldest terrain in the islands, Punta Pitt, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Sea Lion (Zalophus wollebaeki) cow swimming underwater, San Cristobal Island, Galapagos Islands, Ecuador

Pete Oxford / Kicker Rock (Leon Dormido), San Cristobal Island, Galapagos Islands

Pete Oxford / Lava lizard (Tropidurus bivattatus). Punta Pitt, San Cristobal Island, Galapagos

Paul D Stewart / Two Galapagos Mockingbirds (right, upper from Espanola lower from San Cristobal), three Galapagos finch species (upper left) and Yellow Warbler (gold, lower left), from the collection of the Charles D...

Mark Moffett / Aerial view of craterized district, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Sailboat dwarfed by Kicker Rock, an old eroded tuff cone, San Cristobal Island, Galapagos Islands, Ecuador

Tui De Roy / Kicker Rock, old eroded tuff cone, San Cristobal Island, Galapagos Islands, Ecuador