Frankfurt / DPA
Juergen Ebert’s four-wheel-drive vehicle rushes along a path, parallel to an airport runway. His blank gun lets off a loud bang and a flock of starlings flies off. Soon afterwards, a plane roars nearby and takes off: mission accomplished! Ebert is a biologist and leads the wildlife control team at Frankfurt airport, the third-busiest airport in Europe after London Heathrow and Paris Charles de Gaulle. He is there to scare away birds that can put planes at risk.
“We work to ensure a smooth coexistence between nature and airport operations,” Ebert says, describing the job of his four-person team. They are on call every day while the airport is operational, from 5 am until 11 pm, and look after about 620 hectares of woodland, along with 50 hectares of farming land around the airport.
The basic principle is to make life as difficult as possible for birds, not to give them any peace and to deal with open spaces in such a way that birds will have trouble finding their prey. Most collisions between aircraft and birds do not have serious consequences, Ebert notes. But, while about 90 per cent of all cases do not cause damage, exception can be dangerous. “Take-off is more critical than landing, because systems are running at full capacity,” Ebert explains. Birds start to become particularly dangerous when they are the size of a kestrel, which can weight up to 1,400 grams. However, flocks of smaller birds can be equally problematic.
“You cannot achieve 100-per-cent safety,” says Hans Peter Schmid, who deals with the risk posed by birds at Stuttgart airport. There is a downward trend, but it varies depending on conditions for young birds each year.
“You cannot completely free an airport of birds,” Schmid notes. No airport is like any other. Some deal mostly with seabirds like gulls, while others need to focus on birds of prey, the expert says.
In Frankfurt, there are all sorts of species, despite Ebert’s efforts. There are buzzards and kites, kestrels and songbirds, and even aquatic birds. Egyptian, grey and Canada geese are on the rise, and they are the airport’s biggest problem, Ebert notes.
Large spaces on airport grounds are almost never stepped on, so they are also home to species that one would never find in urban areas around them. Skylarks are an example: They are considered an endangered species and they are sensitive to noise, and yet they still like the airport.
“There are no people or dogs here, which is important for ground-nesting birds,” Ebert says. There are about 300 breeding pairs at Frankfurt airport, one of the largest skylark populations on the European mainland. And apparently they’re happy to put up with the noise, given the area’s advantages.
In Frankfurt, whenever a pilot thinks that there may be bird issues, the runway needs to be checked. It is a very busy airport and such operations are messy, Ebert says, so prevention is particularly important.
“Animals want to eat, sleep and breed,” Ebert says. “That is what we try to prevent here at the airport. The area should be made uncomfortable for them.” Spikes are mounted onto signs so that birds will not sit on them. Biologists make sure that green spaces do not hold plants that birds like to eat, particularly certain berries.
Only a certain grass mix is planted. It should not grow too lush and needs to deal well with aridity, holding the soil together and form a thick sward, Ebert says.
The grass is not mowed shorter than 25 centimetres, except on the edges of runways. That way birds of prey are not able to see animals such as mice, while larger swarms do not feel at ease in tall grass.