New Jersey Butterfly Club

River Road Park and Robert J. Stahl Natural Area

by Mike Newlon

County: Somerset.

Municipality: Bedminster Township.

Directions: If driving north on I-287, take exit 22B for US 202/206 North. Stay to the right and in a hundred yards or so take the jughandle left turn at the first traffic light (River Road). Stay to the right on the jughandle and drive straight across US 202/206 on River Road. If driving south on I-287, take exit 22 for US 202/206 North and follow directions as above.
Once across US 202/206, turn right immediately into River Road Park, then left into a gravel parking lot.

Parking: Yes, in addition to the River Road Park parking area described above, there is a smaller parking lot for the Robert Stahl Natural Area west 0.3 miles on River Road on the right.

Nearest sizable town: Pluckemin is a mile or so south on US 202/206; there is a shopping center there at the intersection with Washington Valley Road and a gas station on the other side of the road. Gas stations and restaurants can also be reached north on US 202/206.

Habitats: Meadows, forest, two small ponds, a stream, North Branch of the Raritan River.

Maintained/Marked trails: Yes.

Restrooms: At least in the warmer months, there are portable toilets at River Road Park. To reach them, do not turn left into the gravel lot as described above but continue straight ahead through the stone gateposts, and turn right into a much larger parking area by athletic fields. The toilets are about halfway down the parking area. Currently there are no facilities at the parking lot west on River Road.

Picnic tables: No.

Species recorded: Tiger, Spicebush and Black Swallowtails; Cabbage White, Orange and Clouded Sulfurs; Juniper, Red-banded, and Gray Hairstreaks; Eastern Tailed-Blue; “Summer” Azure; Great Spangled Fritillary; Pearl Crescent, Question Mark; Common Buckeye; Painted Lady; Red-spotted Purple, Little Wood Satyr, Appalachian Brown, Common Woodnymph (can be abundant at the meadow-edge); Common Ringlet (once); Monarch; Silver-spotted Skipper; Southern Cloudywing; Horace’s and Wild Indigo Duskywings; Least Skipper; Northern Broken-Dash; Little Glassywing; European, Swarthy, Peck’s, Zabulon, Hobomok, Dun, and Tawny-edged Skippers; in some years Fiery Skipper and Sachem.

Best time to visit: Mid-to-late summer.

Exploring River Road Park and Stahl Natural Area: The large field to the west has produced Cabbage White, Sulfurs, Swallowtails, Wild Indigo Duskywing, and European Skipper but is steadily being taken over by Mugwort. No trails in this field so take precautions against ticks. Return to River Road, turn right, and drive west 0.3 miles to a smaller parking lot on the right. In summer check the roadside for stands of blooming Knapweed which it may be worthwhile to walk back and check. From the west end of the parking lot, walk the unpaved road away from River Road, between two small ponds, up the rise to the martin houses. At the top of the rise, bear right until you come to a huge meadow. The best butterflying is often between the parking lot and the meadow. A trail runs all the way around the edge of the meadow. Midway down the north side, another trail runs north through woods and a small clearing; another trail branches west from this one, eventually reaching a small stream. On the south side of the meadow there is a stand of Red cedar. From the southeast corner of the large meadow, it is possible to return to the River Road Park lot, but this requires crossing an unbridged drainage ditch, which can be difficult after recent rains.

Other trails in the area: Mostly through forest, so butterflies are scarce on these.

(1) Across River Road from the Stahl Natural Area parking lot, a trail leads through forest to the north branch of the Raritan River, turns east, and returns to River Road near the River Road Park entrance. (2) Across River Road from the River Road Park entrance, a paved bike trail runs south for about 1 mile to Burnt Mills Park in Pluckemin. (3) From the east end of the parking lot by the athletic fields (see Restrooms below) one can cross US 202/206 on a pedestrian bridge to a trail that runs north parallel to the North Branch of the Raritan River (you can also go south but in my experience this area has not been too productive). One can bushwhack or use fisherman’s trails to get to the river’s edge. Eventually you reach a large pond on the left which attracts waterfowl in the cold months, although many of the waterfowl are Canada geese. The trail continues for about ¾ mile and ends at Bedminster Public School. (4) From the east end of the athletic-field lot, it is possible to drive north to the Vandeveer House, a Revolutionary-War historic site. There is a large meadow here which looks attractive, but it is mowed frequently; in my experience it does not produce much in the way of butterflies.

Special precautions: There are no restrictions on getting off-trail in the meadow but if you do, take appropriate precautions against ticks. Note: The trails here are heavily used by equestrians. Please be considerate, move off the trail, and do not disturb the horses.

You might also want to visit: Willowwood Arboretum and Bamboo Brook Outdoor Education Center.