adult babies baby beak bird brood cygnet Cygnus olor England english family Great Britain mute natural nature neck spring Sussex swan waddle young cob crowded feathers flock group plumage swim uk waterfowl white Windsor preen walk head peck background birds color colored colors colour coloured colours cygnus-olor harmonious harmony leisure light paddling pair reflection reflections reflective ripples rippling river riverside river’s-edge serene serenity swans swimming synchronised synchronized tranquil tranquilly water water-birds waterways webbed-feet white-swans