At the time, this film was labelled as a 'horror' film. About a quarter of a century later, Alfred Hitchcock's The Birds is certainly amongst Sir Alfred's most beloved classics. Although it can hardly be considered as a 'horror' film today, it still resists being easily categorised. It features the usual array of Hitchcockian obsessions: a love story with a haughty blonde, slowly revealed family secrets of all the major characters, some comedy scenes, and a thrilling final. So maybe its exact category should be 'Hitchcockian'!
Highly recommended, of course.