Engine failure

I have never known the airport under siege from birds in the way it is at the moment

BA pilot

The danger from large birds was highlighted less than a fortnight ago when a suspected bird strike caused a piece of the engine of a KLM Royal Dutch Airlines 747 fell off.

The plane had to jettison fuel in order to make an emergency landing.

Large flocks are particularly dangerous

In 1995, 24 people were killed when a US military plane crashed in Alaska after flying into a flock of Canada geese.

A BAA spokesman said similar notices to airlines and pilots have been issued at this time in previous years, but the Civil Aviation Authority (CAA) stressed that the problem was worse now than ever before.

A CAA spokesman told BBC News Online: "The population is growing quite dramatically. That is why we have originated a study into assessing their habitats and way of life.

Pilots were issued with a warning

"We have also told landowners around British airports how they can make their lands a less inviting habitat for the birds."

A senior British Airways pilot told The Daily Telegraph: "I have never known the airport under siege from birds in the way it is at the moment.

"We have often had ducks, but Canada geese are much larger and the sheer number of them constitutes a major risk."

The proliferation of Canada geese is also posing a problem for Britain's park rangers.

Last year rangers on Hampstead Heath fed contraceptive pills to Canada geese and pricked hundreds of eggs before they hatched to curb growing numbers.