Friends of Dyke Marsh is a volunteer group dedicated to preserving, restoring and enhancing Dyke Marsh, a freshwater tidal marsh in Fairfax County on the Potomac River just south of Alexandria, Virginia. The Dyke Marsh Wildlife Preserve is administered by the National Park Service.

What Is Dyke Marsh?

The Dyke Marsh Wildlife Preserve is a freshwater, tidal marsh on the Virginia side of the Potomac River in Fairfax County. It is a unit of the George Washington Memorial Parkway, U.S. National Park Service. For more information, visit the NPS website at

FODM Honored by Virginia Legislature

General Assembly

The Virginia General Assembly passed a resolution recognizing the work of the Friends of Dyke Marsh, FODM's 40th anniversary and the 100th anniversary of the national parks system in 2016. The bill's patrons were Senators Scott Surovell and Adam Ebbin and Delegates Paul Krizek and Mark Sickles.

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Spring Brings Breeding Skinks


Spring is breeding time in Dyke Marsh for many species of wildlife, including skinks. The American five-lined skink, (Plestiodon fasciatus), is one of the most commonly seen lizards in eastern North America and is frequently observed around logs along the Haul Road Trail (photo, skinks mating May 2016 by Ed Eder). 

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The Interdependence of Natural Resources


At the quarterly meeting of FODMers and friends on May 11, 2016, Alan Ford and Laura Beaty gave a presentation on the interrelationships of plants and animals and the important role of pollinators and leaf-eaters.  Alan is president of the Potowmack Chapter of the Virginia Native Plant Society and Laura chairs the Propagation Committee.

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Ospreys Are Resourceful, but Fishing Line Is a Danger

great blue heron

Every spring, FODMers welcome the spring return of the ospreys (Pandion haliaetus) to Dyke Marsh and the Potomac River shoreline where these magnificent raptors build and refurbish their nests and raise their young.   In recent years, there have been approximately 10 to 12 active osprey nests within FODM’s breeding bird survey tract, a three-mile area that extends from the Porto Vecchio condominiums near Hunting Creek to south of Morningside Lane.  

Despite the rebound in the osprey population, threats still exist.  On April 18, 2016, FODMer Eldon Boes, a Porto Vecchio resident, reported that the female osprey using the nesting platform on condo property had died after she entangled her primary flight feathers in fishing line.  Eldon removed the fishing line from the nest.

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T.C. Williams Students Visit Dyke Marsh

Canada geese

On the morning of April 29, 2016, 24 students and three teachers from Alexandria’s T.C. Williams High School’s International Academy visited Dyke Marsh to observe in action some of the lessons of their biology class and to try their hand at suppression of invasive plants. 

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Lepidoptera and Odonata Surveys Underway


Volunteers began lepidoptera and odonata surveys in Dyke Marsh on April 20, 2016, led by Jim Waggener. On the 20th, surveyors identified five butterfly species in a brief span.  The peak time for surveys is May through September. This work helps identify and save critical habitat that preserves biodiversity in our region. 

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Raptor Rapture 2016

Peregrine falcon

Under a steady drizzle, a steady stream of raptor fans attended the annual Raptor Rapture in Belle Haven Park on April 23, 2016, sponsored by FODM, the Raptor Conservancy of Virginia and the National Park Service.

Kent Knowles (pictured) and Gabby Hrycyshyn of the Conservancy brought an Eastern screech owl (gray morph), an American kestrel, peregrine falcon (photo), red-tailed hawk, barn owl and Harris’s hawk.  These birds cannot live on their own in the wild. 

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Breeding Birds Are Resourceful in Choosing Nest Sites

Northern rough-winged swallow

As the weather warms, birds are busy breeding in the Dyke Marsh Wildlife Preserve.  In April, FODMers observed red-bellied woodpeckers and northern flickers investigating potential nest cavities, despite facing stiff competition from European starlings.  Observers have seen Carolina chickadees and fish crows carrying nesting material in the Belle Haven picnic area and along the Haul Road. 

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Attacking that Never-Ending Trash


On April 16, 2016, 66 enthusiastic volunteers of all ages turned out on a beautiful spring day and collected trash along the Potomac River and Dyke Marsh shoreline.  The group found plastic bottles, aluminum cans, fast food boxes and wrappers, plastic bags, pieces of Styrofoam, at least two tires and more – too much.

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FODMers Are Testing the Water Flowing into Dyke Marsh

With the assistance of Dan Schwartz, soil scientist, Northern Virginia Soil and Water Conservation District, three FODMers conducted biological quality testing on an unnamed stream flowing into the western part of Dyke Marsh on April 2, 2016.

The group only found 72 invertebrates, fewer than the desired 100, but more than Schwartz had anticipated.

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Frog and Toad Surveys Are Underway

American bullfrog

Thanks to members Laura Sebastianelli and Deborah Hammer, FODMers are conducting a frog and toad survey in Dyke Marsh and other areas, as part of the FrogWatchUSA national monitoring program.  People living near Dyke Marsh West have heard fewer frog and toad calls in recent years and FODM would like to document species and trends.

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Do Trees Have Antifreeze?

Jessie Strother

FODM Board member Jessica Strother, a forester, led a walk on February 27, 2016, and described three of the ecotones of the preserve:  the swamp forest, the floodplain forest and the tidal marsh.  She explained that trees breathe through their leaves and root system.  Trees like the pumpkin ash tolerate water, but cedars like drier, upland soil. 

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