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 learn an aversive response (Izhaki 2002, DeVault et al. 2013).