Eiffel Tower Parrot Cage

Origin
During World War One, parrots were posted at the top of the Eiffel Tower in Paris. Due to their superior hearing ability, they were able to hear incoming aircraft long before any human could, and were trained to squawk loudly if they head any. The practise was stopped because the parrots had no way of determining the difference between German and Allied craft.

Effects
When around active aircraft, the cage shakes and emits squawks loud enough to be heard from up to a mile away. It has the potential to detect aircraft, ranging from biplanes and Boeings to blimps and helicopters, from a distance of twenty miles. For security and safety reasons, it is covered at all times in a large neutralizer cloth.