Answer: Grape Kool-Aid

Oh, what a difference a little physiology makes when it comes to whether or not a substance is delightful or disgusting. Many people, especially children, have a fondness for the fake grape flavor found in Grape Kool-Aid. The flavor is provided by a non-toxic food additive known as methyl anthranilate; this compound also provides the fake grape flavoring in thousands of other products like chewing gum, cough syrup, popsicles, and candies.

While people may love it, birds on the other hand, most certainly do not. When exposed to aerosolized methyl anthranilate, birds experience an irritation of the olfactory system on par with how humans react to breathing in ammonia salt fumes. Wildlife service workers at airports around the U.S. have experimented with using the substance to keep birds away from the runways in a bid to add a new tool to their ever expanding anti-bird arsenal. Should you find yourself waiting to board a flight and you smell jet fuel and grape juice on the wind, you’ll know one of the experiments is afoot.