Pete Oxford / Galapagos Giant Hood Tortoise, saddleback form, female (Geochelone elephantophus hoodensis) Charlse Darwin Research Station. Puerto Ayora, Santa Cruz Island, Galapagos

Pete Oxford / Galapagos Giant Hood Tortoise, saddleback form, female (Geochelone elephantophus hoodensis) Charlse Darwin Research Station. Puerto Ayora, Santa Cruz Island, Galapagos

Pete Oxford / Marine Iguana (Amblyrhynchus cristatus) being cleaned by Darwin's finch, James / Santiago Island, Galapagos Islands, South America

Pete Oxford / Darwin's aster in flower (Darwiniothamnus tenuifolius) Santa Cruz Island, Galapagos

Pete Oxford / Marine Iguana (Amblyrhynchus cristatus) being cleaned by Darwin's finch, vulnerable, Santiago Island, Galapagos Islands, Ecuador

Tom Vezo / Galapagos flycatcher (Myiarchus magnirostris) Galapagos Darwin Centre, Santa Cruz Island, Galapagos

Tom Vezo / Galapagos Flycatcher {Myiarchus magnirostris} Darwin Centre, Santa Cruz Island, Galapagos.

Tom Vezo / Galapagos Flycatcher {Myiarchus magnirostris} portrait on branch, Darwin Centre, Santa Cruz Island, Galapagos.

Pete Oxford / Darwin Bay landscape, Tower / Genovesa Island, Galapagos Islands.

Michael & Patricia Fogden / Darwin's Frog (Rhinoderma darwinii) male on forest floor with vocal sac full of young, austral Beech forest, Chiloe Island, Chile

Michael & Patricia Fogden / Darwin's Frog (Rhinoderma darwinii) male with froglets, in vocal sac, austral rainforest, Chiloe Island, Chile

Michael & Patricia Fogden / Darwin's Frog (Rhinoderma darwinii) male on forest floor with young, austral Beech forest, Chiloe Island, Chile

Michael & Patricia Fogden / Darwin's Frog (Rhinoderma darwinii) male with froglets, in vocal sac, austral rainforest, Chiloe Island, Chile

Mark Moffett / Small Tree-Finch (Camarhynchus parvulus) perching, Floreana Islands, Galapagos Islands, Ecuador

Mark Moffett / Small Tree-Finch (Camarhynchus parvulus) perched in tree, Santiago Island, Galapagos Islands, Ecuador

Mark Moffett / Large Ground Finch (Geospiza magnirostris) feeding, endemic species, extra large bill for cracking large seeds, largest of Darwin's 13 Finches, Santiago Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Brown Pelican (Pelecanus occidentalis) breeding adult bathing, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Darwin's Finch (Geospiza sp) picking ticks from Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi), Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) mature male, one of only two used for captive breeding, Charles Darwin Research Station, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) showing beak shape for crushing large seeds, Academy Bay, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) endemic, extra large bill for cracking large seeds, largest of the 13 species of Darwin's Finches, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with fully inflated throat pouch, Darwin Bay, Genovesa

Tui De Roy / Galapagos Sea Lion (Zalophus wollebaeki) subadult bulls sparring, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Brown Pelican (Pelecanus occidentalis) adult in resplendent breeding colors, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Warbler Finch (Certhidea olivacea) endemic small insectivore, one of 13 species of Darwin's Finches, Genovesa Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) endemic, extra large bill for cracking large seeds, largest of the 13 species of Darwin's Finches, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) endemic, extra large bill for cracking large seeds, largest of the 13 species of Darwin's Finches, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Warbler Finch (Certhidea olivacea) endemic small insectivore, one of 13 species of Darwin's Finches, Genovesa Island, Galapagos Islands, Ecuador

Tui De Roy / Great Frigatebird (Fregata minor) male in courtship display with extended gular pouch, Darwin Bay, Genovesa Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Darwin's Finch (Geospiza sp) group picking ticks from Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi), Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Red-footed Booby (Sula sula) white morph pair building nest in tree, Culpepper Island, Galapagos Islands, Ecuador

Tui De Roy / Red-footed Booby (Sula sula) nesting birds flying back to isolated island at dusk, Culpepper Island, Galapagos Islands, Ecuador

Tui De Roy / Sharp-beaked Ground-Finch (Geospiza difficilis) drawing blood from base of Masked Booby (Sula dactylatra) feathers, an adaptation unique to Wenman Island, Galapagos Islands, Ecuador

Tui De Roy / Cocos Finch (Pinaroloxias inornata) 14th Darwin Finch that lives in dense rainforest, Cocos Island, Costa Rica

Tui De Roy / Eroded volcanic tufa arch, world class dive site, Darwin Island, Galapagos Islands, Ecuador

Tui De Roy / Layered lava cliffs of Darwin Island, Galapagos Islands, Ecuador

Tui De Roy / Sooty Tern (Onychoprion fuscatus) pair courting, easternmost Pacific Ocean colony, Culpepper Island, Galapagos Islands, Ecuador

Tui De Roy / Small Ground-Finch (Geospiza fuliginosa) feeding on sedge seeds, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Small Ground-Finch (Geospiza fuliginosa) female feeding on sedge seeds, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Small Ground-Finch (Geospiza fuliginosa) male feeding on Opuntia (Opuntia sp) cactus fruit, Santa Fe Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) portrait, Tower Island, Galapagos Islands, Ecuador

Tui De Roy / Medium Ground-Finch (Geospiza fortis) female in breeding plumage, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) mature male, one of only two used for captive animal breeding, Charles Darwin Research Station, Santa Cruz Island, Galapagos Islands, Ecuado...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) mature male, one of only two used for captive animal breeding, Charles Darwin Research Station, Santa Cruz Island, Galapagos Islands, Ecuado...

Tui De Roy / Saddleback Galapagos Tortoise (Chelonoidis nigra hoodensis) mature male, one of only two used for captive animal breeding, Charles Darwin Research Station, Santa Cruz Island, Galapagos Islands, Ecuado...

Tui De Roy / Pinta Island Galapagos Tortoise (Chelonoidis nigra abingdoni), Lonesome George, the last survivor of his race, Darwin Reserve Station, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Darwin's Finch (Geospiza sp) group picking ticks from Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi), Alcedo Volcano, Isabella Island, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra) hatchlings checked on by park warden, Galapagos Islands, Ecuador Giant Tortoise at Charles Darwin Research Station, Galapagos Islands, Ecuador

Tui De Roy / Volcan Alcedo Giant Tortoise (Chelonoidis nigra vandenburghi) at Charles Darwin Research Station, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra) field trip to show children wild tortoises, Charles Darwin Research Station, Galapagos Islands, Ecuador

Tui De Roy / Galapagos Giant Tortoise (Chelonoidis nigra) hatchling emerging from egg in incubator, Charles Darwin Research Station, Galapagos Islands, Ecuador

Pete Oxford / Darwin Bay, Tagus Cove, Isabela Island, Galapagos Is.

Pete Oxford / Darwin Bay, Tagus Cove, Isabela Island, Galapagos Is.

Pete Oxford / Hood or Saddleback tortoise {Geochelone elephantopus hoodensi} looking up at leaves, Darwin Research Centre, Hood Is, Galapagos

Pete Oxford / Hood (Saddleback) tortoise {Geochelone elephantopus hoodensi}, Hood Isl, Galapagos Darwin Research Centre

Paul D Stewart / Sailing ship off Galapagos (Daphne Major island in background) and Giant Tortoise (Chelonoidis nigra), photo composite. The Galapagos were visited by Charles Darwin in his Beagle voyages and also by a...

Paul D Stewart / Illustration of 'Albemarle Island' (now Isabela) engraving by Huyot and Bepard facing page 520 in 'All Around the World' published in 1872 by William Collins & Son. Shows the large caldera of a volcan...

Paul D Stewart / Illustration of 'Albemarle Island' (now Isabela) hand coloured engraving by Huyot and Bepard facing page 520 in 'All Around the World' published in 1872 by William Collins & Son. Shows the large calde...

Paul D Stewart / A Galapagos Mockingbird, from the collection of the Charles Darwin Research Station on Galapagos. While actually on the Beagle voyage, it was the mockinbirds, and not the celebrated finches gave Darwi...

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...

Paul D Stewart / Illustration of the extinct Falkland Island Wolf or Fox (Dusicyon australis). Hand coloured lithograph, Plate IV, The Zoology of the Voyage of H.M.S. Beagle, edited and superintended by Charles Darwin...

Pete Oxford / Cars on Charles Darwin Avenue, Puerto Ayora, Santa Cruz Island, Galapagos Islands, Ecuador

Tui De Roy / Green Sea Turtle (Chelonia mydas) with Steel Pompanos (Trachinotus stilbe) rubbing on its shell, Culpepper Island, Galapagos Islands, Ecuador

Tui De Roy / Large Ground Finch (Geospiza magnirostris) feeding on Angiosperm (Scutia sp) seeds, Santa Cruz Island, Galapagos Islands, Ecuador