Airports seek ways to scare off birds

The Shanghai Airport Authority has been blasting bird calls from roving vehicles and launching explosives into the air as it tries out approaches to keep birds from flying into planes, local media reported Tuesday.

The measures aim to curtail the number of bird strikes at the city's airports this year. Although bird strikes rarely cause crashes, they cost airlines and airports financially in delays and extra maintenance costs. According to the Civil Aviation Administration of China (CAAC), bird strikes cost the commercial aviation industry about 1.2 billion yuan ($188.86 million) each year.

Outside Shanghai Hongqiao International Airport, a vehicle equipped with a loud speaker plays bird calls before takeoffs and landings, according to a report in the Shanghai Morning Post.

The vehicle broadcasts bird sounds at frequencies outside the normal range of human hearing 24 hours a day. The sounds have been effective at scaring birds away from the airport.

To drive off birds that intrude on airport airspace, workers employ an explosive device they call an "aerial bomb" that makes a loud noise and produces smoke, the report said.

Large birds like egrets and hawks are the most common to visit Hongqiao airport.

According to domestic aviation regulations, airports are supposed to limit the frequency of bird strikes to fewer than three for every 100,000 flights, the news website Zhejiang Online reported.

A total of 23,303 flights took off or landed at Pudong International Airport last month, according to the Shanghai Airport Authority.

Hongqiao airport has seen fewer birds this year than in 2011, said Chen Jiang, the general manager of the airport's airfield management department.

Because the bird situation varies at airports around the country, the CAAC has given airport authorities license to try out a variety of methods to keep birds out of the way of arriving and departing aircraft, said Zhao Xinru, a bird expert and professor at Beijing Normal University.

"Currently, we still lack statistics about which machine is most effective at keeping birds away," Zhao told the Global Times. "Sometimes, we humans believe that a machine will be effective because it sounds scary to our own ears, but we need to try it out to know for sure whether it works on birds."