Wildlife Damage Management, Internet Center for


Date of this Version

Fall 2009


Published in Human–Wildlife Conflicts 3(2):237–241, Fall 2009, pp. 237-241. Published by the Jack H. Berryman Institute.


Tree swallows (Tachycineta bicolor) have been a periodic bird-strike problem at John F. Kennedy International Airport (JFKIA), New York, New York, causing runway closures, flight delays, and damage to aircraft following the ingestion of bird flocks into engines. We examined 65 tree swallows collected at JFKIA in October 2001 to determine food sources that were attracting the birds to the airport. Digestive tracts of all 65 specimens contained northern bayberry fruits (Myrica pensylvanica), averaging 15.6 fruits per bird or 3.4% of the bird’s body mass in specimens where the entire tract was dissected. Bayberry fruits are a highly attractive food source for tree swallows, especially during fall migration when insects are limited. Beginning late in 2001, a bayberry removal program was instituted at JFKIA. We examined tree swallow strike reports from JFKIA before and after this program began and found a 75% reduction in the number of strikes after removal of bayberry bushes. Removal of bayberry from coastal airports like JFKIA may facilitate the dispersal of tree swallow flocks that use airports as resting sites during their migration and may reduce the risk to birds and dangerous encounters with aircraft, thus limiting problems caused by runway closures and flight delays.