Other birds are attracted to swan habitats for reasons of safety

The Vale of Glamorgan Council wants to reduce the population of 150 swans at Cold Knap at Barry by two-thirds.

Other wild birds are attracted because swans only live in safe areas.

The lake will be drained and cleaned. A council spokesman said: "The potential problem is caused by ducks and geese flocking into the flight path."

The council's head of visible services, Miles Punter, said the authority hoped that temporarily draining the lake would in turn will persuade some of the swans' feathered friends to move somewhere else.

But bird charity the RSPB did not believe it would work.

The RSPB's Stuart Thompson said: "I don't think the council are going to solve things by draining the lake because swans are very site-faithful.

"They will probably come back when the lake is filled up again.

"I appreciate they are trying to do this using non-lethal methods but I don't associate swans with being a problem with aircraft.

"It's more geese because they fly higher and faster," said Mr Thompson.

"The main problem with draining the pond is going to be finding a food source.

"The thing to do would be to create something for the birds elsewhere."

Mr Thompson said he did not think the presence of swans themselves attracted other birds but they were all attracted by food available at The Knap.

He said large groups of swans could sometimes deter other birds from landing.

Cardiff International Airport welcomed the council recommendations and said it had monitor and reduce the risk to planes.