A military airport has sought the help of monkeys to remove birds' nests that pose a threat to flight safety, according to the Chinese air force.
"Our airfield is located along one of the eight flyways, the East Asian-Australasian Flyway, so large numbers of migrating birds come here around March every year and begin nesting near the airport, which creates significant safety hazards for flight," Su Chuang, head of the bird control team at an unidentified airbase of Beijing Military Command, told People's Liberation Army Daily.
The nests must be removed, but shooting or knocking them down with bamboo sticks is inefficient, he said.
During a recent brainstorming session, officers at the airbase came up with an unusual idea: using monkeys to destroy the birds' nests, according to Wang Yuejian, commander of the airbase.
Civilian animal experts worked with officers to design training programs for the monkeys, and two rhesus macaque monkeys have finished their training, Wang said.
The monkeys will shake the limb supporting the nest to make it drop from the tree. "Our statistics show that the two monkeys have taken out about 180 nests over the past month," Wang said.
Compared with traditional ways of dispersing birds, the new method is eco-friendly and has a minimal effect on the birds, he added.
"Birds from the same species will never build their nests at the same place where our monkeys remove them because our 'demolisher' will leave its smell on the tree, which is sensed by the birds as a threat."
Birds often build nests near busy airports because they are usually placed on the fringe of large urban centers and frequently have large tracts of unused, undeveloped land surrounding them as noise and safety buffers, according to Melissa Mayntz, a member of the Cornell Lab of Ornithology under Cornell University.
The undeveloped land is attractive to birds, particularly as suitable habitats shrink due to urban expansion, she said.
In 2013, planes landing at or taking off from New York City's John F Kennedy International Airport struck birds on 174 separate occasions, according to the United States Federal Aviation Administration.
Compared with civil planes, military aircraft are particularly susceptible to bird strikes.
An F-16 fighter jet of the US air force went down near Luke Air Force Base in suburban Phoenix, Arizona, in June due to an engine malfunction after hitting a bird shortly after takeoff. The two pilots ejected safely, and the fighter jet crashed in a farm field near the base.
In November, a Chinese navy fighter jet almost crashed after hitting a bird.