In the study, 10 untrained Goffin’s cockatoos faced a puzzle box showing a nut behind a transparent door secured by a series of five different interlocking devices, each one jamming the next along in the series. To retrieve the nut the birds had to first remove a pin, then a screw, then a bolt, then turn a wheel 90 degrees, and then shift a latch sideways. § One bird, called Pipin, cracked the problem unassisted in less than two hours, and several others did it after being helped either by being presented with the series of locks incrementally or being allowed to watch a skilled partner doing it.