Cuckoos are nest parasites. That means they lay eggs in the nests of other birds, which then put the effort into raising the chicks. So you'd think they'd be quiet about it. Yet female cuckoos have a ...

This circuit generates a two-tone effect very much alike the cuckoo song. It can be used for door-bells or other purposes thanks to a built-in audio amplifier and loudspeaker. Agreeable, very close ...