Fountainhead Regional Park skirts the shore of the Occoquan Reservoir. From the marina you can view a broad expanse of the reservoir and search for bald eagles, osprey, and a variety of waterfowl. More importantly, Fountainhead Regional Park is the southernmost trailhead for the Bull Run-Occoquan Trail. This marvelous park offers an extensive trail network through deciduous forest. These woods are home to many breeding woodpeckers, warblers, thrushes, and owls. Expect the diversity to explode during migration. You may also want to look for interesting shade butterflies during the summer.