IMPERIAL, Pa. (August 3, 2012)--A beekeeper says he was called in to gather up a swarm of thousands of bees that delayed the departure of a Delta Air Lines flight from Pittsburgh International Airport to New York.

Master beekeeper Stephen Repasky told KDKA-TV he was called out on Wednesday after the bees gathered on the wing as crews were getting ready to refuel the plane.

Repasky said such swarms form when colonies become too large and the queen leaves half of her bees behind to find a new home.

Some swarms can contain 25,000 to 30,000 bees.

Repasky says it's likely there's a wild honeybee colony at the airport somewhere.

The beekeeper was called to remove the insects because they're a protected species that cannot legally be killed.