exploders (Washburn et al. 2006). Pyrotechnics utilizing either an exploding shell or a screamer can effectively scare birds away from runways. They are commonly launched from a 12 gauge shotgun or a flare pistol, or from a wireless specialized launcher and as such, can be aimed to allow control personnel to "steer" the species that is being harassed. Birds show varying degrees of habituation to pyrotechnics. Studies have shown that lethal reinforcement of pyrotechnic harassment has extended its usefulness (Baxter and Allen 2008). Screamer type cartridges are still intact at the end of their flight (as opposed to exploding shells that destroy themselves) constituting a foreign object damage hazard and must be picked up. The use of pyrotechnics is considered "take" by the U.S. Fish and Wildlife Service (USFWS) and USFWS must be consulted if federally threatened or endangered species could be affected. Pyrotechnics are a potential fire hazard and must be deployed judiciously in dry conditions (Commander, Naval Installations Command, 2010, Airport Cooperative Research Program 2011). Bioacoustics, or the playing of conspecific distress or predator calls to frighten animals, is widely used. This method relies on the animal's evolutionary danger response (Airport Cooperative Research Program 2011).However, bioacoustics are species-specific and birds may quickly become habituated to them and they should not be used as a primary means of control (U.S. Air Force 2004, Commander, Naval Installations Command 2010). In 2012, operators at Gloucestershire Airport in the United Kingdom revealed that songs by the American-Swiss singer Tina Turner were more effective than animal noises for scaring birds from its runways. Tactile repellents Sharpened spikes to deter perching and loafing are commonly used. Generally, large birds require different applications than small birds do (DeVault et al. 2013). Chemical repellents There are only two chemical bird repellents registered for use in the United States. They are methyl anthranilate and anthraquinone. Methyl anthranilate is a primary repellent that produces an immediate unpleasant sensation that is reflexive and does not have to be learned. As such it is most effective for transient populations of birds (DeVault et al. 2013). Methyl anthranilate has been used with great success at rapidly dispersing birds from flight lines at Homestead Air Reserve Station (Engeman et al. 2002). Anthraquinone is a secondary repellent that has a laxative effect that is not instantaneous. Because of this it is most effective on resident populations of wildlife that will have time to