Frightening devices used successfully against gulls include shotgun shells, shellcrackers, gas-powered exploders, and broadcasts of distress and alarm calls (see "Bird Dispersal Techniques" at the following Web site: http://icwdm.org/handbook/birds/Dispersal.asp).
Trained border collies have been used with great success to harass gulls. In addition, gulls can be harassed by trained birds of prey or radio-controlled small aircraft, which can be constructed to resemble falcons. To be successful, all scaring devices should be used by experienced, dedicated personnel. Continuity and care in use are the most important factors.
Most distress and alarm calls are species-specific and may even be specific to local dialects. They must be used sparingly to avoid familiarity and are best used from a stationary source. The birds will first approach the source of sound and after 5 to 10 minutes will move away from the area. Shellcrackers can be used to direct the departure. They are most effective when the birds are airborne and have begun to move away from the sound source.
Frightening devices are not a cure for repeated presence of gulls. Dead gulls or gull decoys placed in dead gull postures can be used, especially in conjunction with other frightening devices to frighten gulls from an area.
Avitrol® concentrate (4-aminopyri-dine) is federally registered for the control of herring gulls in the United States. The current label allows for its use to frighten gulls that are feeding, nesting, loafing, or roosting near or in the vicinity of sanitary landfills, airports, and structures. Apply the concentrate to bread, as specified on the product label. Mortality is minimized by limiting the amount of bait offered. Avitrol® used for this purpose is a Restricted Use Pesticide. State and federal permits are required in order to use Avitrol® on gulls.
Resources: (online)
