We wish, not for the first time, we knew a simple way. The trouble is, docks and rafts are ideal hangouts for waterfowl, particularly mergansers, mallards, Canada geese, and gulls. "From the birds' point of view, these areas offer security," says Ron Black, a wildlife biologist with the Ministry of Natural Resources (MNR) in Parry Sound, Ont. "Right at the water, with easy access, where you can see predators coming from any direction - the perfect rest stop." Wildlife biologist Jan McDonnell, at the MNR's Bracebridge, Ont., office, has observed merganser mothers with their large broods lined up at dawn on a dock, clearly confident that this is their rightful territory. "You could try putting a row of chairs or an old rolled-up tarp in their favourite spot, around the time of day they like to arrive," she suggests. "But I'm not saying they're easy to discourage. And gulls are even harder."

Rigging up a perimeter barrier of yellow caution tape or fishing line can help keep ducks and geese away, Black says, because they usually hop up onto a dock or raft from the water. It's less useful for gulls, which are more likely to fly in. You can always try an owl decoy, maybe fastened to the tip of a slender fishing pole, so it moves in the breeze. But, like any other deterrent, it'll work only until the birds discover it's safe to ignore. "Try one thing, then something else, or a combination of things," says McDonnell, "and hope to get the birds out of the habit."