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A closed section of Fairfax County’s I-95 landfill has become valuable habitat for dozens of bird species, including several facing regional or continental conservation concerns.
The transformation follows a 2024 decision to designate 50 acres of the 500-acre landfill as a no-mow zone. Acting with support from the Board of Supervisors and at the urging of the Northern Virginia Bird Alliance, landfill managers agreed to suspend mowing during the grassland nesting season and raise mower blades to eight inches when mowing resumed.
Surveys conducted in 2024 and 2025 indicate that the modified maintenance schedule is working. County staff concluded that the meadowlike area continues to provide critical habitat during peak breeding and nesting months.
Kimberly Lewis, a county staff member, said Eastern meadowlarks, grasshopper sparrows and other species are thriving on the 50-acre grassland created atop the landfill.
Surveys Find More Species
In 2025, county intern Blair Evancho joined staff members and volunteers for weekly surveys from May 1 through July 12. The team recorded every species observed and confirmed 40 species in the no-mow area, up from 29 in 2024.
Four of the species recorded in 2025 are considered of regional or continental concern: the chimney swift, grasshopper sparrow, Eastern meadowlark and bobolink.
The grasshopper sparrow was the most frequently detected species. That finding was especially notable because the ground-nesting bird has experienced regional population declines.
Duane Wright, director of the county’s Solid Waste Management Program, said the monitoring shows that the landfill complex offers meaningful habitat for grassland birds, including species of conservation interest. He said the results demonstrate how careful land management can support environmental stewardship while meeting the site’s long-term maintenance needs.
At least one Northern Virginia Bird Alliance volunteer participated on each survey day, alliance President Libby Lyons said. She praised the county’s approach and expressed hope that it could become a model for conservation efforts at other landfills.
June Mowing Disrupted Bird Activity
The 2025 project encountered a setback when unplanned mowing occurred on three days in June during work on a new solar field beside the protected area. Surveyors noticed a decline in bird activity on those dates.
The mowing conflicted with a protocol that prohibits cutting vegetation in the no-mow zone during the April-through-September breeding season, except when access to monitoring wells is necessary.
A Scarce Habitat Finds an Unlikely Home
Grassland birds depend on open fields for nesting and generally cannot substitute other habitats when those areas disappear. Their populations have fallen 43% since 1970, according to the North American Bird Conservation Initiative’s 2025 State of the Birds report, with habitat loss identified as the main cause.
Most natural grasslands in the eastern United States have vanished. Virginia has retained only a tiny fraction of the grasslands that existed when European colonists arrived in the 1600s. Biologist Justin Folks has estimated that the remaining share may be less than 0.0001%.
Ornithologist Greg Butcher has described the landfill as the largest grassland patch in eastern Fairfax County. Closed landfills are commonly capped and planted with grasses to stabilize their surfaces, creating the potential for carefully managed sites to serve another ecological purpose.
Wright said maintaining a clearly defined seasonal no-mow period allows nesting and foraging to continue while the county keeps the landfill maintained and environmentally secure. The approach, he said, recognizes that closed landfill areas can still contribute to the region’s broader ecosystem.