The term 'graceful seabird' can be broken down into two crossword solutions: ERNE (4 letters) and TERN (4 letters). ERNE is a type of large, fish-eating bird of the family Accipitridae, which includes hawks, eagles, and kites. It is found in Europe, Asia, and North America. TERN is a type of seabird of the family Laridae, which includes gulls, skimmers, and auks. It is found in temperate and tropical regions around the world. Both ERNE and TERN are graceful birds that can be seen flying over the ocean.