Trapping
Trapping is used if a local population becomes a nuisance. The secret to trapping is to pre-bait for about one week before setting the trap. Also, remember that birds can learn quickly how to escape a trap, so it may be necessary to try different types of traps to keep the birds from becoming trap shy or trap smart.
Multi Catch Trap
When large numbers of birds are a nuisance, funnel or drop-in multi-catch traps are used. Some crafty birds have learned to come and go through a funnel trap as easily as a person walks through a doorway. By adding bobs to the funnel entrance you can out-smart those individuals. Many traps can be homemade and funnel entrance traps are also commercially available. Some traps like the elevator traps are only available in garden supply catalogs. In some situations numerous birds can be trapped at one time with a clap-net trap (examples of the clap-trap are the clap-net, consisting of two nets laid flat on the ground and attached to cords in such a manner that they fly up and close when the draw-cord is pulled by a concealed trapper; and the various other spring-traps used by bird-catchers). The sieve trap and the nest box traps are effective for taking a few nuisance individuals.
Tactile Repellents
Tactile repellents may be either mechanical like porcupine wire, wire loops, electrified wires on roosting surfaces, or sticky substances, that usually containing polybutene. They make surfaces uncomfortable or impossible for birds to roost on. Tactile repellents are usually used on resting surfaces used by pigeons.
Sound Repellents
Sound has long been used to scare away birds. Loud noises like those produced by firearms, pyrotechnics, or propane exploders may scare away flocks of bird from a particular area for a short time. Unless the noises are randomly discharged, the birds quickly learn to ignore the sound. Also, producing loud noises randomly during all daylight hours will quickly irritate all but the most understanding neighbors and may violate noise ordinances.
Ultrasonic devices
To get around the problems noises present people have tried ultrasonic devices. These produce sounds above the human threshold of hearing. Ultrasonic waves reflect off objects, rather than going around them, producing sound shadows where the birds can avoid the sound. In general, ultrasonic devices rarely drive bird from established home ranges. Further, research at Purdue University has shown that some of these devices have caused hearing loss in dogs. Another use of sound involves using recorded distress calls of the target bird species. Originally calls were recorded on tape and played back. Now calls can be digitally stored on a chip and programmed to be played in a random pattern. The birds may eventually learn to recognize that particular call over time and ignore it, but this type of auditory scare device may prove effective longer than previous startle devices.
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