Earthworms are an attractant to birds, such as gulls, blackbirds, and starlings. These birds, in turn, can pose a severe threat to aviation safety. When worms emerge from underground due to heavy rains, they often crawl onto airport runways where they attract foraging flocks of birds. In September 2004 at Calgary International Airport, two aircraft (a Boeing 737 and an Airbus 319) obtained significant damage when they struck gulls during takeoff. Investigations showed the gulls had been attracted to the airport to feed on earthworms that had crawled onto the runways.
NWRC scientists at the Sandusky, OH, field station are evaluating the use of physical and chemical barriers to prevent earthworms from moving onto runways where they would be attractive to foraging birds. One method being studied is the use of fertilizers that earthworms find chemically irritating. Fertilizers can also alter soil pH which can drive worms away from the affected area. Another barrier being tested is recycled glass or remnants from coal burning facilities crushed to the size of large, sharp sand particles. When placed on the soil surface the materials creates an abrasive, dry, and acidic layer that earthworms avoid.