swallow-tailed gull creagrus furcatus mating at genovesa island, galapagos islands

america avian beach behaviour bird birds breeding colony creagrus darwin ecuador endemic eyes fauna furcatus galapagos genovesa grey gull island laridae latin legs mating national nature nesting ocean ornithology outdoors pacific pair park plumage red rimmed rock sea seagull sitting south swallow swallowtailed tailed tropical two vertebrate white wild wildlife