The term 'Northern Diving Bird' can be summarized by two crossword solutions: AUK (3 letters) and Murre (5 letters). AUK is a type of seabird that is found in the Northern Hemisphere, particularly in the Arctic and Subarctic regions. It is a member of the Alcidae family and is characterized by its short wings and webbed feet. Murre is also a type of seabird that is found in the Northern Hemisphere, particularly in the North Atlantic and North Pacific oceans. It is a member of the Alcidae family and is characterized by its black and white plumage, long wings, and short tail. Both AUK and Murre are excellent swimmers and divers, and they feed mainly on fish and other aquatic organisms.