Chubu Electric Power Co. has adopted a unique method to deter crows from nesting on transmission towers and causing blackouts by building artificial bird nests far from the power lines.
Until recently, the company tried chasing the birds away from the towers with little success. Instead, the company found that providing “love nests” for mating crows is more effective in ensuring that the electricity flows without interruption.
“It looks like the baby has fledged and left the nest safely,” Takahiro Sugiura said as he viewed a transmission tower with binoculars.
Sugiura is a 23-year-old employee handling power transmission at the Hamamatsu electric center, a unit of Chubu Electric in Shizuoka Prefecture.
A basket made of resin about 40 cm in diameter was placed high on the tower away from the power lines.
The center has installed baskets in 327 of the 1,120 towers it manages, selecting those structures on flat ground where crows tend to build their nests.
Nesting typically begins between February and May.
Crows often use metal clothes hangers and twigs as a base material, but they don’t hold up well to wind and rain and tend to fall away. Sometimes when this happens the hangars get caught in the power lines, causing a short circuit.
Of the failures that occur in power facilities managed by Chubu Electric, approximately 100 a year are caused by crows, second only to lightning strikes, which account for a few hundred cases.
During the nesting season, Chubu Electric and other utilities are kept busy climbing towers to remove crow nests.
Electric companies have installed bird spikes and stretched wires around beams to prevent crows from building nests on the towers, but the birds can usually get around such obstacles and continue building their nests.
It was the Hamamatsu electric center, which suffers particularly heavy damage from nests in Chubu Electric’s coverage area, that came up with the plan to build safer alternatives for the birds.
When they began installing artificial nests in 2004, many mating crows started moving in and laying eggs.
The artificial nests have significantly reduced the number of natural nests that have to be removed and have reduced the risk of power outages.
After seeing the positive results, Chubu Electric has now placed more than 2,000 artificial nests in five prefectures — Aichi, Gifu, Mie, Shizuoka and Nagano.
Hoping to encourage even more crows to use the artificial nests, the center last year put some in towers where they had removed natural ones, but in places where they won’t interfere with the power supply.
As a result, the rate of artificial nest usage increased by 4 percentage points to 67 percent compared with the previous year.
Not only has the number of natural nests decreased, dispatching staff to clear nests from transmission towers has been reduced from 55 times a year to 27.
It costs ¥15,000 to purchase and install an artificial nest, but only ¥5,000 to move it to a different location.
Based on the center’s analysis, 90 percent of crows like to build their nest 30 to 50 meters above ground, which explains why they prefer transmission towers.
“The more effectively we install artificial nests, the more crows use them,” said Hiroshi Saito, 52, assistant head of the center’s power supply department.
“Instead of leaving it up to the crows to decide where to nest, we must guess the best locations for them to do so and work on preventing power failures,” he added, asking people to let the utility know when they find natural crow nests on power facilities.
This section, appearing Tuesdays, features topics and issues from the Chubu region covered by the Chunichi Shimbun. The original article was published May 9.