This horror movie about vampire bats was first released in the same year as a then major new version of 'Dracula' (1979) starring Frank Langella as the Count. That movie was one of five Dracula movies made and first released around 1979. The films are Dracula (1979), Nosferatu the Vampyre (1979), Love at First Bite (1979), Nocturna (1979), and Dracula Blows His Cool (1979). Also from 1979 were the vampire movies Thirst (1979) and Salem's Lot (1979).
Bracken Cave Preserve, where the real life bat footage was shot, is the largest bat colony in the world and home to over twenty million Mexican free-tailed bats (also known as the ''Tadarida brasiliensis'' species). The site is located less than twenty miles from San Antonio, Texas and is situated in the southern part of the state's Comal County.
The Texas filming location of Bracken Cave near San Antonio, which was used by documentary filmmaker David Saxon to shoot the real footage of real bats for the film, was the same site that he had used for his National Geographic television special on bats entitled 'Strange Creatures of the Night' (1973) (TV). This earlier program had been narrated by Leslie Nielsen who later starred as the title character in Mel Brook's vampire spoof 'Dracula: Dead and Loving It' (1995).
The film was made and first released (in 1979) about two years after its source novel of the same name (in 1977) by author Martin Cruz Smith.
The movie was filmed in four states: Texas, Nevada, New Mexico, and California.