Ключевые слова: algarve, basic plumage, birds, blacknecked grebe, body parts, cluster, coat, europe, feather, feathering, flock, grebe, migrating, nonbreeding plumage, podiceps nigricollis, podicipedidae, podicipediformes, portugal, swarm, water birds, waterfowl, winter plumage, winterkleid,