Unpleasant sounds could deter wild animals from accessing an area if they are disturbed or scared of the sounds.
One study from India (Arora et al. 2023) found that installing a bioacoustics device to prevent bird damage on guava, somewhat reduced fruit damage in the treatment compared to the control plots during the rainy season developing stage (RR = 0.36), rainy season ripening stage (RR = 0.36), winter season developing stage (RR = 0.41) and the winter season ripening stage (RR = 0.34). In California, USA, researchers installed a portable tape player connected to amplified trumpet speaker to broadcast species specific alarm and distress calls to deter house finches (Carpodacus mexicanus) and European starlings (Sturnus vulgaris) from plucking and pecking wine grapes. Broadcasting units were placed at a density of 0.6 ha per broadcast unit, concentrated on the perimeter of the vineyard, and moved weekly in a fixed pattern. Vineyards with the intervention installed observed lower levels of damage than without the broadcasting unit (RR = 0.57). A study (Werrell et al. 2021) in North Dakota, USA, investigated the effect of a Sonic Net (1–8 kHz at 80 dBA SPL) to prevent damage from black birds (Icteridae) to sunflowers, and found that the average damaged area per plant was 62 % lower in the treatment fields than in the control. In Connecticut, USA, exploders were employed to deter red-winged blackbirds (Agelaius phoeniceus) and common grackles (Quiscalus quiscula) from damaging corn (Conover 1984). In comparison to unprotected controls, damage was reduced to the total yield (RR = 0.23) and the proportion of damaged ears (RR = 0.43) in fields with exploders.
Alarm and distress calls of deer were broadcast from a unit with infrared activation function to prevent damage from white-tailed deer (Odocoileus virginianus) on corn yield in Nebraska (Glisdorf et al. 2004a). The yield reported by farmers was around 13 % higher in treatment fields, but the difference was not significant. Propane exploders (Thunderbird Scare Away, Reed-Joseph International, Greenville, Miss.) were also found to be ineffective in reducing white-tailed deer damage to corn (Glisdorf et al. 2004b).
