The Homing-Hummer is a special bird whistle which sends out high-frequency “homing tones” that all birds respond to, but human beings cannot hear. It was invented by Gyro Gearloose in 1969 to allow him to quickly test his Animated Feline Scarecrow on a wide variety of birds. Once he'd done so, Gyro gave the whistle to Huey, Dewey and Louie Duck so they could use it for their Junior Woodchucks Birdwatching Project. While they were doing this, Donald Duck briefly, accidentally swallowed the whistle, which set in motion a series of events culminating in the dismantling of a spy ring.
The Homing-Hummer is central to the events of the 1969 story Bird-Bothered Hero.