Fighting the feathered foe

Press, 15 January 1986, Page 1

Fighting the feathered foe

By

DAVID WILSON

Birds do not scare easily or for long, and airport authorities world wide are waging a continual battle of wits against them. Just which side gets the better of the confrontation is highly debatable. At Christchurch, the problem has again come under the spotlight after an Air New Zealand report into an incident involving one of its Boeing 747 s during take-off last July. Bird ingestion crippled two of the aircraft’s four engines and caused it to turn back for an emergency landing. Researchers at airports throughout the world are pitting their skills against the cunning of the winged enemy, but so far no longterm deterrent has been found.

Birds quickly adapt to new techniques employed

against them. Is it because they are too clever, too stubborn ...or just plain stupid? “It’s their inbred instinct for survival,” says the Civil Aviation manager at Christchurch Airport, Mr John Laing, who has been engaged in the battle with the birds for the last five years. Birds had been recognised as a potential hazard to aircraft since the inception of the first aeroplane service, he said. The advent of jet-engined aircraft had dramatically increased the problem. “With the coming of the turbine-engined aircraft a number of new problems were suddenly introduced,” said Mr Laing. “Engine noise levels preceding the aircraft were considerably lower, aircraft speeds and accelerations increased rapidly, and the tremendous airflow into tur-

bine engine intakes added a new danger which birds could not sense.”

Many techniques have been tried at leading airports. These include: • Gas-fired guns set off at intervals — birds soon learned that the explosions were not harmful and moved only a few metres. • The old-fashioned shotgun method — birds gauge the gun’s range. • Plastic models of dead seagulls as a warning — the ruse did not work for long. In England, ’ taperecordings of bird distress calls have been used with some success.

“In co-operation with Wildlife Service people in Wellington we have been trying to record birds’ distress calls, but so far we haven’t had much luck,” said Mr Laing. “We could try the tapes from the United Kingdom,

but birds have dialects, believe it or not, and it’s extremely unlikely that recordings of northern hemisphere distress calls would be understood by the birds here.

“Researchers in the United States and Britain are now looking at the possibility of using a sonic wave device, and I believe that could well be the answer,” he said. Aviation Security Service patrols at Christchurch are mounting a dual offensive; shotguns combined with twin-explosive cracker shells.

The shells explode first at ground level as they are fired from a pistol, then seconds later a secondary and louder explosion occurs at 40m to 50m.

This puts the birds into an explosion “sandwich” and creates enough confusion to

make them fly a reasonable distance away. Aviation Security maintains a 24-hour patrol of the airport perimeter. In the last six weeks they have shot 40 birds.

The type of ground cover at an airport is important also. The Christchurch Airport authority is now planting aphis-free lucerne and letting it grow to about 30cm before cutting.

"Normally birds like to have all-round vision when they are on the ground,” said Mr Laing. “They’re not happy in long grass and there has been a reduction of the numbers of birds in areas where we have planted this type of grass. “It’s a question of using every resource we can get our hands on, and trying to think one step ahead of the birds all the time,” Mr Laing said.