Geese Are Trouble For Homeowners, Naturalists Alike

"They damage the wetland ecosystem, and that in turn affects the other native animals that would depend on the habitat both for cover and food," Swarth said. "We'll have to manage the geese from here on out. It's going to be a constant issue."

The Maryland-National Park and Planning Commission, which oversees park land in Montgomery and Prince George's counties, has resorted to using two border collies to keep the geese away. Officials are also addling, or shaking, goose eggs so that they don't hatch, said Marion Joyce, a commission spokeswoman.

"If you remove the eggs or crush the eggs, the geese will either build another nest and reproduce, or just reproduce more eggs," she said. With "egg addling, the geese are less likely to abandon the nest and make a new one."

Egg addling or euthanizing geese require a permit from the U.S. Fish and Wildlife Service because the geese are protected under the Migratory Bird Treaty Act. During the proper season, licensed hunters in Maryland are also allowed to kill Canada geese.

At the Needwood Golf Course in Rockville, a border collie named Daniel is used to chase off the big birds. In the early morning, he shoos them away, even jumping in the course's pond if necessary. And in the evening, after the geese have returned, he chases them again, said Brian Blake, the course superintendent.

Before the course had a dog, geese were everywhere, tearing up the greens and distracting the players. But the worst problem, Blake said, was the poop they left.

The Jug Bay Wetlands Sanctuary also appears to be making strides in fending off the geese. Thanks to hunts and the fencing, "the marsh is making a tremendous comeback," said Greg Kearns, a Patuxent River Park naturalist who has also worked with Jug Bay.

But the damage from the geese has been telling. Kearns said he had noticed that fewer birds, such as sora rail, redwing blackbirds and bobolinks, were nesting in the marshes. That's because the geese had taken over, devouring thousands of acres that would normally provide food and shelter to the other birds, Kearns said.

"It's just been incredible," he said. "We never dreamed they would cause this much damage. They have changed the entire composition of the marsh."