High-frequency and high-amplitude sounds enhance bird deterrence.

Given the widespread conflicts between humans and birds in contexts such as agricultural production, airports, and new energy installations, the development and application of bird deterrence technologies hold significant importance for both safeguarding human interests and advancing the cause of wildlife conservation. Artificial sounds are one of the most widely used methods for bird deterrence; however, there is a lack of systematic research on the effects of sound frequency and their combination. The black-necked crane (Grus nigricollis), a first-class nationally protected wild animal of China, shares some of its habitats with human agricultural activities. This study designed sounds of various frequencies and combinations and conducted deterrence experiments on black-necked cranes at their wintering sites in northeastern Yunnan Province, exploring how sound frequency and combinations affect the behavioral responses, escape distances, and escape speeds of the cranes. Our results show that: (1) in terms of behavioral response intensity, escape distances, and escape speed, sounds with high frequency and high variability significantly outperformed other sounds (n = 479, p < 0.001); (2) there were no significant differences in the responses of black-necked cranes of different flock types and age combinations to sounds. The study recommends using high-frequency, highly variable sounds for short-term control of black-necked cranes. Additionally, this research demonstrates that using either high-frequency or high variable sound combinations can achieve efficient bird deterrence in the short term, and provides a scientific basis for developing and refining bird deterrence strategies for other bird species.