Birds can be a dangerous obstacle to airplanes landing and taking off at most airports. It's looking very possible that American Airline Flight 587 may have crashed because a bird (or birds) was ingested by at least one of the plane's engines. At John F. Kennedy International Airport, birds may be more of a problem due to the proximity of a well-known wildlife sanctuary run by the National Parks Service a few miles south of the airport in Jamaica Bay. The refuge is home to a variety of birds—including thousands of migrating geese that descend on the lagoon in the fall. Any kind of bird can be a hazard to airplanes, but geese pose a special problem because they are big and they fly in large numbers. The seriousness of the geese presence at Kennedy is so great that the airport employs snipers to try and ward off anything that might stray into the flight path of a plane, as James Kaplan describes in his book The Airport: Planes, People, Triumphs, and Disasters at John F. Kennedy International.
A 1995 report from Transport
If a goose is ingested by an engine, especially on take-off when the turbine is roaring at full throttle, the consequences can be disastrous. The effect of a bird entering an airplane engine is akin to a brick hitting a pane of glass: The turbine shatters. All engines are designed to try and avert such a catastrophe and to prevent the wrecked engine from damaging other parts of the plane. They also contain extinguishers so that a damaged turbine can be closed down and fire put out. Yet just a few pieces of shrapnel spat out from the crippled turbine at high speed can lead to further and more critical damage—to a wing or to the fuselage.