Mercer County, Pennsylvania, offers a variety of opportunities for birdwatchers, especially those interested in native waterfowl. With its blend of wetlands, lakes, and protected woodlands, the region supports a variety of birds throughout the year.
Whether you’re hoping to catch sight of spring migrants, breeding pairs in the summer, or large flocks staging for fall migration, Mercer County’s lakes provide prime vantage points.
In this guide, we’ll explore three of the top birdwatching destinations, Lake Wilhelm, Shenango River Lake, and Sandy Lake, and the native waterfowl species most commonly seen at each.
Located in the northern part of Mercer County, Lake Wilhelm is the centerpiece of Maurice K. Goddard State Park. This 1,860-acre reservoir is encircled by a variety of habitats, including forests, wetlands, and meadows, making it an exceptional site for observing a diverse bird species throughout the year.
Waterfowl to Watch For
Lake Wilhelm serves as a great stopover for migratory waterfowl during the spring and fall migrations. Birdwatchers can expect to see common loons, known for their eerie, yodel-like calls and dagger-shaped bills, gliding over the lake’s open waters.
Diving ducks such as ring-necked ducks, which have a subtle chestnut ring around their necks and striking golden eyes, and redheads, easily recognized by their vibrant cinnamon-red heads and slate-gray bodies, gather in deeper sections.
Red-breasted mergansers, with their spiky crests and long, serrated bills, also frequent the lake’s deeper zones. Dabbling ducks like green-winged teal—the smallest dabblers, sporting a vivid green wing patch—can be found in the marshy inlets, alongside American black ducks, mallards with their iridescent green heads, and northern shovelers, whose oversized spoon-shaped bills make them distinctive feeders.
In the warmer months, the lake’s quiet backwaters and reedy edges provide breeding grounds for hooded mergansers, whose fan-shaped crests give them a unique helmeted look, and pied-billed grebes, small diving birds with a chunky build and a black-ringed bill. Wood ducks, with their brilliant, multicolored plumage and expressive red eyes, and Canada geese, recognizable by their black necks and white chinstraps, are commonly observed year-round.
Spring welcomes gadwalls, subtly marked with gray, brown, and black, with a surprisingly intricate feather pattern, while buffleheads, tiny, energetic divers with bold black-and-white heads and lesser scaup—noted for their bluish bills and round heads—are also common.
Autumn brings species like ruddy ducks, which in breeding plumage feature chestnut bodies and blue bills, along with flocks of American coots and common mergansers, large, sleek diving ducks with sharp red bills and a strong presence.
The park also supports notable summer residents such as the towering great blue heron, the fish-snatching belted kingfisher with its rattling call and shaggy crest, and the osprey, a fish hawk with dramatic black eye stripes and a wingspan of 5-6 feet.
Ospreys have successfully nested at Lake Wilhelm for several years, and a designated viewing platform across from the marina provides excellent views of their nesting and hunting behavior.
Best Times to Visit
The prime birdwatching periods at Lake Wilhelm are from March through May and late September through November, aligning with peak migratory activity. Early mornings during these times provide calm waters and active feeding behaviors, offering optimal conditions for spotting and photographing birds.
For those interested in nesting activities and warm-weather residents, late spring into summer offers excellent opportunities to witness the breeding behaviors of birds like wood ducks, purple martins (a glossy blue-black swallow known for communal nesting), and ospreys, particularly near designated nesting boxes and secluded backwater habitats throughout the park.
Stretching across south-central Mercer County, Shenango River Lake is managed by the U.S. Army Corps of Engineers. It is well-known for its expansive open water, floodplains, and adjacent wetlands. This habitat diversity draws a wide array of native waterfowl.
Waterfowl to Watch For
Shenango River Lake hosts a wide variety of waterfowl throughout the year, with peak diversity seen during the spring and fall migrations. Mallards and Canada geese are abundant and present in all seasons, often foraging along shorelines or cruising the lake’s open waters.
During migration seasons, the lake becomes a vital rest stop for many species. Notable visitors include tundra swans, majestic white birds with black bills that migrate in noisy, elegant flocks, and northern pintails, as well as sleek ducks with long necks and elegant, pointed tail feathers. Green-winged teal are also common in shallow wetlands, flashing emerald wing bars as they dart away in flight.
Deeper reservoir zones attract red-breasted and common mergansers, both excellent fish hunters with sharp, serrated bills. Buffleheads and lesser scaup add lively movement to the migration season, diving and resurfacing in fast-paced rhythms.
Lucky visitors may even spot more elusive species, such as canvasbacks, with their sloped foreheads and striking red eyes; ruddy ducks in their distinctive courtship colors; and redheads, often mingling in mixed-species rafts.
Best Times to Visit
The best times to observe waterfowl at Shenango River Lake are during the spring (March-May) and fall (August–November) migrations, when both numbers and species diversity peak. Early morning visits offer the best lighting and bird activity.
A special seasonal highlight occurs from late summer through early fall when receding water levels expose large mudflats and aquatic vegetation. This temporary habitat attracts impressive numbers of waterfowl and shorebirds, making Shenango River Lake one of the top birding hotspots in western Pennsylvania, south of Lake Erie.
Pack your binoculars, a field guide, and some patience, and you’ll likely be rewarded with sightings of some of Pennsylvania’s most beautiful native waterfowl.
Each lake offers something unique to birdwatchers:
Lake Wilhelm delivers variety and scale, making it ideal for more extended visits and scanning large numbers of birds.
Shenango River Lake is perfect for observing waterfowl on the move and offers excellent diversity in deeper waters and wetlands.
Whether you’re an experienced birdwatcher or just starting out, Mercer County’s waterways are a destination worth exploring.
