From New York Summer Guide:

Earlier this spring, Lee Humberg directed a small team of biologists to Rikers Island in an effort to avoid the unavoidable. They were on a mission to find young, baseball-size eggs, five or six per nest, and slather them with enough oil so that they would not hatch furry yellow goslings that would grow to become airplane-*threatening geese the size of winged dogs. Humberg, a wildlife biologist and district supervisor for the Animal and Plant Health Inspection Service, an agency within the U.S. Department of Agriculture, pointed his team to the shore of the island, just a few dozen yards from the runways at La Guardia, where they watched for lone ganders on guard. Following protocol, one team member warded off the gander and hen—each hissing, neck stretched in alarm—while a second sprayed each egg with corn oil, a process known as addling. It takes only a few minutes to addle a nest full of eggs, after which the parent geese return to their old routine, unaware that their eggs are unlikely to hatch.

Summer Guide 2011 - The Lonely Life of the Goose Killer -- New York Magazine