working in the hangar. (U.S. Air Force 2004, Commander, Naval Installations Command 2010). Visual repellents There have been a variety of visual repellent and harassment techniques used in airport wildlife management. They include using birds of prey and dogs, effigies, landing lights, and lasers. Birds of prey have been used with great effectiveness at landfills where there were large populations of feeding gulls (Cook et al. 2008). Dogs have also been used with success as visual deterrents and means of harassment for birds at airfields (DeVault et al. 2013). However, airport wildlife managers must consider the risk of knowingly releasing animals in the airport environment. Both birds of prey and dogs must be monitored by a handler when deployed and must be cared for, when not deployed. Airport wildlife managers must consider the economics of these methods (Seamans 2001). Effigies of both predators and conspecifics have been used with success to disperse gulls and vultures. The effigies of conspecifics are often placed in unnatural positions where they can freely move with the wind. Effigies have been found to be the most effective in situations where the nuisance birds have other options (e.g. other forage, loafing, and roosting areas) available. Time to habituation varies. (Seamans et al. 2007, DeVault et al. 2013). Lasers have been used with success to disperse several species of birds. However, lasers are species-specific as certain species will only react to certain wavelengths. Lasers become more effective as ambient light levels decrease, thereby limiting effectiveness during daylight hours. Some species show a very short time to habituation (Airport Cooperative Research Program, 2011). The risks of lasers to aircrews must be evaluated when determining whether or not to deploy lasers on airfields. Southampton Airport utilizes a laser device which disables the laser past a certain elevation, eliminating the risk of the beam being shone directly at aircraft and air traffic control tower (Southampton Airport 2014). Auditory repellents Auditory repellents are commonly used in both agricultural and aviation contexts. Devices such as propane exploders (cannons), pyrotechnics, and bioacoustics are frequently deployed on airports. Propane exploders are capable of creating noises of approximately 130 decibels (Wildlife Control Supplies). They can be programmed to fire at designated intervals, can be remote controlled, or motion activated. Due to their stationary and often predictable nature, wildlife quickly becomes habituated to propane cannons. Lethal control may be used to extend the effectiveness of propane