Adult Swallow-tailed gull (Creagrus furcatus) on Espanola Island in the Galapagos Island Archipelago, UNESCO World Heritage Site, Ecuador, South America

creagrus furcatus espanola island galapagos ecuador birdwatching wildlife avian marine nature coastal environmental animal habitat shore seaside gray plumage black head red eyes beak perched serene landscape island species conservation ecology distinct features daytime shoreside rocky terrain biodiversity migrant endemic tropical ocean south america fauna vibrant animal behavior ecological significance natural habitat observation ornithology cliffside marine ecosystem