A distiller's what? 

A distiller's parrot is positioned so as to allow the distillate to flow through it on its way from the condenser to the collection vessel.  It holds the hydrometer/alcoholmeter so that alcohol percentage readings can be taken at any time during the distillation process without having to collect small fractions in separate containers.

To set up, the parrot is placed in position so that the distillate will enter the parrot inlet and the parrot outlet can empty into the collection vessel.  Once in operation, the parrot reservoir will be filled with distillate entering at the bottom of the tube.  This constantly pushes the older distillate out at the top of the tube and away to be collected, thus allowing alcoholmeter readings to be taken in real time.  Important Note: The parrot should not be connected until foreshots have been collected and disgarded in order to avoid contamination.