Bird beaks come in a variety of shapes and sizes, depending on the species. The two crossword solutions for the term 'bird beaks' are NIBS and NEBS. NIBS stands for 'Nibbling', which is the act of taking small bites with the beak. NEBS stands for 'Nebbing', which is the act of using the beak to probe or explore an object. Both nibbling and nebbing are important behaviors for birds, as they use their beaks to feed, groom, and explore their environment.