Pre-programmed digital bird sounds of popular songbirds and Purple Martins. Features Volume Control. 50 foot AC cord included. Designed in consultation with ornithologists and biologists for maximum realism. Natural recordings represent multiple individual birds, each song set to play at naturally occurring intervals. Photocell senses natural light for automated activation at dawn to entice birds. Digital recordings more durable than tapes. Weatherproof construction. Mountable.