Mallards — the familiar ducks of city parks — are one of a group of closely related species, many of which are far less common. Interbreeding can threaten the genetic distinctiveness of those other species and cause concern for their conservation. A new study investigates hybridization between mallards and mottled ducks, a species adapted for life in coastal marshes, and finds that while hybridization rates are currently low, human activity could cause them to rise in the future.