At a Glance

Hours: Daylight hours year-round. The sanctuary is located in a residential area and care should be taken to avoid disturbing the neighbors.

Cost: Free. Donations to the MOS Sanctuary Fund are always appreciated.

Tips: Wear sturdy footwear as the ground is rocky. ◾ Be alert for Timber Rattlesnakes, black bears, and bobcats. ◾ Public roads in the area of the sanctuary may be closed, and the sanctuary may be inaccessible, when the US President is visiting Camp David. Check for information and detours. ◾ Hunting is not permitted on sanctuary grounds, but may take place on neighboring lands. Be aware of hunting seasons and plan your visit accordingly. Wear blaze orange during hunting season. ◾ No restrooms.

Best Seasons: Spring and fall migration and early summer for breeding birds.

Breeding Bird Atlas Block: Blue Ridge Summit CE (Click on Atlas Block name for list of breeding birds from 1st and 2nd Atlases). Read about the MD & DC Breeding Bird Atlases.

Local MOS Chapter: Frederick Bird Club

Seymour B. Cooper MOS Sanctuary

Between 7001 and 7127 Eylers Valley Flint Road, Sabillasville, MD 21780
GPS Coordinates 39.671422, -77.420969
Contact: MOS Sanctuary Chair

Seymour B. Cooper MOS Sanctuary is a 14.3-acre tract of land located in the Catoctin Mountains of Frederick County, north of Thurmont. It is located in Eyler Valley (aka Eyeler Valley) on the lower slope of 1700-foot Piney Mountain, just a short distance from Camp David and Catoctin Mountain Park, and 3.3 miles south of the Pennsylvania state line. “No Hunting” signs indicate the boundaries and painted stakes mark the corners of the property. There is a large wooden sign with the name of the sanctuary, but this is set back from the road and not easily seen when the trees are in leaf.

The sanctuary is covered entirely by second-growth deciduous forest consisting mostly of oaks and maples. Chestnut Oak is the dominant tree, and the canopy averages 60-80 feet in height. The presence of American Chestnut saplings and older fallen logs indicate that this area was probably logged around the time of the Chestnut blight. There is a sparse ground cover of ferns and small shrubs; the middle layer of the understory is mostly lacking. There are no streams or other waterways on the sanctuary, although there may be springs.

There are no established trails in the sanctuary, but a remnant of an old logging road starts at the west corner of the property along Eylers Valley Flint Road, and heads southeast into the heart of the sanctuary. Not used by vehicles since the 1960s or earlier, this road is now little more than a trail, marked mostly by traces of gravel along parts of its path. The old logging road runs very near the property line for the sanctuary. Do not stray to the south as you will be on private land. Obey the No Trespassing signs.

Although there are no marked trails, the understory of the sanctuary is relatively open and the entirety of the sanctuary can be easily explored on foot. Be aware that the ground is studded with rocks and boulders that present trip hazards as well as possible hiding places for Timber Rattlesnakes. Sturdy hiking boots are recommended. Also be on the alert for Black Bears and Bobcats, both of which frequent the area.

MOS acquired this land as a gift from the Nature Conservancy, which had received it from the widow of the late Seymour B. Cooper. Mrs. Cooper wished to establish a nature preserve in her husband’s memory, as he was an avid outdoorsman.


The eBird hotspot for Seymour B. Cooper MOS Sanctuary lists 52 species as of July 2022, but only twelve checklists have been submitted since the hotspot was established in 2017.  Seymour Cooper is seriously under-birded, and hence only an incomplete discussion of its birdlife is possible at this time. Additional species would no doubt be recorded with more visitation and submission of eBird checklists. In particular, it would be helpful if birders could visit and submit eBird checklists to the Atlas portal during breeding season, during the five years of the Third Breeding Atlas project (2020-2024). Spring and fall migration have also been virtually ignored.

Canada Geese and Mallards may occur as flyovers, probably commuting to or from Rainbow Lake in the Emmittsburg Watershed (about 2.25 miles to the northeast, as the crow flies) or some other nearby pond or wetland. Great Blue Herons may also be seen as flyovers.

Rock Pigeons are also possible as flyovers from nearby farms. Mourning Doves are present on the property. Yellow-billed Cuckoos occur during breeding season.

Both Black and Turkey Vultures are common overhead. Sharp-shinned Hawks have been seen in early spring. Red-shouldered and Red-tailed Hawks have been flyovers in fall.

Red-headed Woodpeckers occur in the wider area, and there is one report from the Sanctuary. Red-bellied Woodpeckers can be found at any time of year, and Pileated Woodpeckers are also found here. Downy and Hairy Woodpeckers and Northern Flickers have been surprisingly scarce, but that may be an artifact of the low number of eBird checklists.

In the summer, flycatchers include Eastern Wood-Pewee, Acadian Flycatcher, Eastern Phoebe, and Great Crested Flycatcher. Blue-headed and Red-eyed Vireos are also present during summer breeding season.

Blue Jays and American Crows are found throughout the year, and there is one report of flyover Common Raven. Ravens have been widely reported from the area.

As you might expect, Carolina Chickadees and Tufted Titmice are common. Given the proximity of the sanctuary to Pennsylvania, Black-capped Chickadees are a distinct possibility, and birders should be alert for them, especially in winter. Ruby-crowned Kinglets linger through spring. White-breasted Nuthatches are also present, and Brown Creepers may be present in winter (one report).

Carolina Wrens are present, probably year-round. Gray Catbirds and Northern Mockingbirds are known from only single reports, along with Eastern Bluebirds. Wood Thrushes are present during breeding season.

American Goldfinches, Chipping Sparrows, Ovenbirds, Scarlet Tanagers, and Northern Cardinals have all been reported during breeding season.

By comparison with the bird list for Seymour Cooper Sanctuary, the Blue Ridge Summit CE Atlas Block, within which the sanctuary is located, had a total of 71 species during the first Breeding Bird Atlas, and a total of 83 species during the Second Breeding Bird Atlas; see the species list for the previous atlases.  These longer lists of species could be considered as your target list for visits to Seymour Cooper; all of these birds would not be breeding on the sanctuary itself, but because they breed in the area they could be observed in or near the sanctuary.

If you want to try for additional species diversity when birding at Seymour Cooper, be aware that there is a wetland, about 10 acres in size, on private land across the road from the sanctuary. This wetland is not visible from the road, but lies in a stream valley within a forested area less than 250 feet from the north side of Eylers Valley Flint Road and just west of Debold Road. The wetland is in a drainage area surrounding a small stream that runs the length of Eylers Valley between Catoctin Mountain to the north and Little Piney Mountain to the south. The wetland may attract a different community of birds from what we see on the higher ground of the sanctuary. The land containing the wetland is private and should not be entered, but you can listen carefully for singing birds from Eylers Valley Flint Road or along Debold Road, especially at the small bridge just 200 feet north of the Debold Road intersection with Eylers Valley Road.

Pet Policy:

Pets are allowed on leash; be prepared to pick up after your pet. Do not allow dogs to run off leash or bark excessively, as this may disturb the neighbors. Also do not allow pets to dig and damage plants.

Wheelchair Access:

The sanctuary has no maintained trails and penetration into the sanctuary is not possible for someone in a wheelchair or using a walker. Some birding is possible from the paved road or from the car parked at the edge of the sanctuary.

Special Designations and Conservation Value:

Seymour B. Cooper MOS Sanctuary lies within the Maryland Blue Ridge Important Bird Area (IBA), as designated by the National Audubon Society.

Seymour Cooper Sanctuary lies within an area classified by the Maryland Department of Natural Resources (DNR) as a Targeted Ecological Area. Targeted Ecological Areas are lands and watersheds identified by the Maryland Department of Natural Resources as the most ecologically valuable areas in the State; they are considered the “Best of the Best” and receive priority for conservation by the State. For more information on how DNR prioritizes land for conservation, see the DNR information sheet “GreenPrint Lands Are Important.”

The sanctuary is in an area categorized by the MD Department of Natural Resources as a Green Infrastructure Wildlife Hub and Corridor. Green Infrastructure identifies the State’s remaining large blocks of forest and wetlands (hubs) and the habitat pathways (corridors) that connect them. For more information on how DNR prioritizes land for conservation, see the DNR information sheet “GreenPrint Lands Are Important.”

Seymour B. Cooper MOS Sanctuary is also located in an area classified by MD DNR as Tier 3 – Highly Significant for Biodiversity Conservation under their Bionet – Biological Diversity Conservation Network initiative.

MD DNR offers a Parcel Evaluation Tool that provides an analysis of conservation benefits for a particular parcel of land. Using this tool, Seymour B. Cooper MOS Sanctuary scores

  • 5 stars out of 5 for providing “Habitat Connectivity.”
  • 4 stars out of 5 for providing “Rare Species and Wildlife Habitat.”
  • 3 stars out of 5 for “Support of Aquatic Life.”
  • 5 stars out of 5 for “Forests Important for Water Quality Protection.”
  • 3 stars out of 5 for “Proximity to Other Protected Land,” presenting conservation opportunities that contribute to landscape scale protection which is key for conserving healthy aquatic and terrestrial ecosystems.

The parcel evaluation tool shows that the ecosystem services provided by Seymour Cooper Sanctuary are valued at $2,321.31 per acre per year, or $33,705.42 for the entire 14+ acre tract.

Special Features:

The local chapter of the Maryland Ornithological Society is the Frederick Bird Club, offering field trips and meetings with informative programs, all free and open to the public.


There is sufficient space on the road shoulder for three or four cars near the house at #7001 Eylers Valley Flint Road (see sanctuary map). Be careful not to block the private driveway and pull your car entirely off the road. If you go farther east along the road, parking is not possible because of a roadside ditch.


Seymour B. Cooper MOS Sanctuary is located in the Catoctin Mountains north of Thurmont in Frederick County.

Street address: Between 7001 and 7127 Eylers Valley Flint Road, Sabillasville, MD 21780

GPS Coordinates: 39.671422, -77.420969

From the Washington, DC area: From the DC Beltway (I-495), take I-270 northwest to Frederick. At Frederick, follow signs to merge onto US Route 15 northbound. Stay on Route 15 for approximately 18 miles. After passing the town of Thurmont, turn left to go north on MD Route 550/Sabillasville Road. Stay on Sabillasville Road for 2.9 miles, then turn right to go east on Eylers Valley Flint Road. The sanctuary will be on the right in 1.6 miles, between houses at #7001 and #7127. Park on the shoulder on the right, just past the driveway for #7001.

From the west (Hagerstown and beyond) OR from the east (Baltimore): Take I-70 to the Frederick area. Follow signs to merge onto US Route 15 northbound. Stay on Route 15 for approximately 18 miles. After passing the town of Thurmont, turn left to go north on MD Route 550/Sabillasville Road. Stay on Sabillasville Road for 2.9 miles, then turn right to go east on Eylers Valley Flint Road. The sanctuary will be on the right in 1.6 miles, between houses at #7001 and #7127. Park on the shoulder on the right, just past the driveway for #7001.

Nearby Sites:

Frederick County: Audrey Carroll Audubon SanctuaryC&O Canal – Mouth of Monocacy to BrunswickCatoctin Mountain Park ◾ Cunningham Falls State Park ◾ Fred J. Archibald Audubon Sanctuary ◾ Gambrill State Park ◾ Lilypons Water GardensSugarloaf Mountain


Upland Deciduous

Features and Amenities:

BeginnersFree - No Entry Fee at Any TimeParkingPets Allowed


Audubon Important Bird AreasMOS Sanctuaries