Adult black guillemot (Cepphus grylle) in summer plumage near Vigur Island in Isafjardardjup Bay, Iceland

black guillemot cepphus grylle summer plumage vigur island isafjardardjup bay iceland seabird wildlife coastal habitat bird behavior feathers flapping wings marine life nature ornithology colors rocky shore seaweed avifauna flight preparation aquatic environment birdwatching animal nesting ecosystem interaction fauna natural season change ecology identification species conservation ornithological study outdoor activities