Drones Scare Away Crows With Sounds (2)

Developed jointly by power producer, venture firm

2019/09/10 00:04
Shinichi Kato, Nikkei BP Intelligence Group, CleanTech Labo

Continued from Drones Scare Away Crows With Sounds (1)

ECO-5 develops and sells systems to prevent damage caused by birds and animals, including wild boars, deer and crows, using the sounds of birds and animals. Sounds of natural enemies and sounds that crows generate when they are attacked by natural enemies are combined and produced from various places, using a stationary system equipped with speakers.

According to Yoichi Nagano, president of ECO-5, the effects do not last long if such sounds are produced from speakers in the same way. Measures to prevent the birds and animals from getting used to the sounds are important, including frequent relocation of the stationary system, changing the generated sound depending on the speaker and occasionally changing the sounds.

One of the secrets to sustained effects seems to be the environment in which crows do not know where the sounds come from, timing of generation and sound type.

As measures against crows, sounds of natural enemies such as hawks, falcons and eagles, as well as a variety of sounds including hunting guns, sounds that crows produce when they are scared and sounds of sea ducks, which may be unexpected, are produced from speakers. Crows are especially clever, and the key points are the types of effective sounds and how they are produced.

At the solar power plant of Japan Environment Techno, 10 speakers are installed on the ground for repelling animals. Eight of them are for scaring away crows and the remaining two are for repelling wild boars. Slopes of nearby mountains are often dug by wild boars, and barking sounds of dogs are produced from the two speakers at night to prevent the wild boars digging.

When the stationary speakers were introduced, crows were scared and flew away, and the number declined rapidly. It was also confirmed that the effects will last longer if the speaker locations and sound types are changed.

Based on this background, Japan Environment Techno thought a more effective crow repelling method would be realized if the system was used in combination with drones, which the company handles as another core business. The effects are limited when priority is placed on either the stationary system or a drone; however, continuous effects are realized by a combination of the two, Komuro said.

A compact drone was initially used to check the effects at the power plant. The effects of the sounds were confirmed, but it was observed the drone was attacked by crows because it was small. It was also found that the output of the speaker mounted on the compact drone was insufficient to increase the sound volume to a level that scares crows.

Based on the results, the drone was replaced with a more appropriate one, and the speaker output was increased. The drone body needed to be larger for stable flight carrying a speaker. The increase in the drone body was also effective for stopping crows from attacking the drone (Fig. 2).

Fig. 2: Drone currently flown twice a month (source: Japan Environment Techno)

Materials that generate reflecting lights were also attached to the drone body later to visually scare away crows among other measures.

Special skills are required in flying the drone. It is more effective when slow flight and hovering are combined than flying it at high speed while producing the sounds. The drone is flown differently for scaring away wild boars and deer.

Following introduction of the new crow repelling method established as introduced above, almost no crows approach the solar power plant operated by Japan Environment Techno now, and damage due to droppings has decreased significantly.

Farmers and livestock farmers near the plant were initially shocked by the scary sounds and their volume, but are cooperating now because they know they also can benefit from the anti-crow measures.

Based on the effect of scaring away crows, the interval of producing sounds from stationary speakers was increased from one minute to five minutes, and the frequency of producing sounds using a drone was reduced to twice per month. Even after the changes, similar effects are maintained.

Japan Environment Techno and ECO-5 also plan to promote the sale of the devices needed to repel crows and the knowhow.