So-called bird strikes are increasingly common as wind power-generation facilities are built across Japan, prompting a variety of measures to protect wild birds, including making the turbines clearly visible to birds and using sound to ward them off.
In Hokkaido, many white-tailed sea eagles – an endangered bird listed in the Environment Ministry’s Red Data Book – have been killed due to hitting wind turbines.
At Tomamae municipal Yuhigaoka Power Plant in Hokkaido, there are three wind turbines atop a cliff overlooking the Sea of Japan. On the lower part of one of the turbines are 14 circular stickers, each one meter in diameter and placed at regular intervals.
With black circles in their centers, the stickers resemble eyes. Although the wind turbines were not rotating the day I visited due to low winds, a municipal official in charge of wind power generation said: “When strong winds blow during winter, the turbines turn at full capacity and their efficiency increases. We haven’t seen any birds get struck by the turbines since attaching the stickers in July last year.”
Last fiscal year, electricity sales at the plant, which began operations in 1999, brought in revenue of about ¥77 million. Since the plant started generating power, carcasses of white-tailed sea eagles have been found near the wind turbines.
The white-tailed sea eagle is designated as a Vulnerable Species in the ministry’s Red Data Book because its risk of becoming extinct is increasing.
According to the ministry, there were 42 cases nationwide of white-tailed sea eagles being injured or killed in bird strikes from 2004 to March 2015. Of those, only one was found alive. Excluding two cases in Aomori Prefecture, the remaining 40 were all in Hokkaido; of those, 23 were in Tomamae.
Tomamae’s eye stickers were placed on the turbines in July last year with support from the Environment Ministry. As white-tailed sea eagles feed on river and sea fish, they usually look downward when they fly. It is believed this makes them prone to collisions, because they fail to notice wind turbines in front of them.
To make wind turbines more noticeable to birds, the town decided to introduce the stickers of eyes – which birds are known to dislike.
Wind turbines are practically invisible when they rotate at high speeds, which is another contributing factor. It is also believed that visibility is reduced by snow in cold regions, and white turbines blend into the background.
According to the Wild Bird Society of Japan, which has been collecting data on all wild birds injured or killed by bird strikes since 2001, there have been 341 cases across 11 prefectures – including Iwate, Fukushima and Ehime but excluding Hokkaido and Aomori.
Tatsuya Ura, a senior researcher at the society, said: “There are cases of carcasses being eaten by other animals, which leave no trace of accidents. More birds are probably being killed.”
Researchers have yet to find a surefire method of preventing bird strikes. Last year, the Environment Ministry conducted a series of experiments at a cape in Nemuro, Hokkaido, using a device that emits the sounds of gunfire.
Although many birds reacted to the sound by slowing down or temporarily flying higher, there were only a few that changed direction in response to the sound. A U.S. study suggests that scaring birds with scarecrows does not have a lasting effect.
Maps of high-risk regions
According to the New Energy and Industrial Technology Development Organization, there were 2,102 wind power generators nationwide as of fiscal 2015, a 3 percent increase from the previous fiscal year.
Operators of large-scale power generators are required by the Environmental Impact Assessment Law to assess the effects of wind turbines on wild bird populations prior to construction.
However, Prof. Yasushi Maruyama of Nagoya University, an environmental sociology expert, said, “Damage prediction has its limits, because it’s difficult to know exactly what types of birds and how many of them inhabit a particular area.”
For this reason, experts are trying to create a map that pinpoints regions where wind power generators are likely to have a negative impact on wild bird populations. A study group comprising the Wild Bird Society of Japan, university researchers and power companies was established in Hokkaido in March. It has started preparations for creating maps for Wakkanai, Toyotomi and Horonobe, where there are plans to build large-scale wind power plants.
The group plans to divide targeted areas into sections five kilometers square and then conduct ecological surveys on birds in each section. It will then make a color-coded map showing high-risk areas. It aims to complete the task within two years.
The Environment Ministry is also planning to create a similar map this fiscal year that would cover Hokkaido and the Tohoku region.
According to Ura, who is participating in mapping work, “We want to spread this initiative across the country to reduce bird strikes and create an environment in which birds and wind turbines can coexist.”
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