In early April of each year, we like to take a dreary-day stroll along the Susquehanna in Harrisburg to see if any waterfowl or seabirds have dropped in for a layover before continuing their journey from wintering waters along the Atlantic seaboard to breeding areas well to our north and northwest. As showers started to subside this Saturday morning past, here are some of the travelers we had the chance to see…
Hundreds of scaup were feeding at mid-river. To remain in suitable foraging habitat, the group is seen here flying upstream to the area of the Governor’s Mansion where they would commence yet another drift downstream to Independence Island before again repositioning to a favorable spot.By far, the majority of the ducks in this flock were Lesser Scaup showing white inner margins of the secondary flight feathers and more grayish margins in the primaries. Several Greater Scaup, including the one denoted by the hairline in this image, could be detected by the presence of bright white margins not only in the secondary flight feathers, but extending through the primaries as well.A pair of Lesser Scaup feeding along the river shoreline at the Governor’s Mansion. Both scaup species spend the colder months in bays and coastal estuaries, but the Lesser Scaup is the most likely to be found venturing inland to fresh water in the southern United States during winter. The Lesser Scaup nests in the northwestern United States and in the southern half of Canada. The Greater Scaup is the more northerly nesting species, spending its summers at the northern edges of the border provinces and beyond.Common Loons spend the winter in Atlantic surf. April is the best time to see them on the lower Susquehanna River as they drop in to rest and reenergize during a break in their annual northbound trip to nesting sites on the lakes and ponds left behind by the retreat of Pleistocene glaciers.We saw dozens of Buffleheads during our morning hike, often segregated into paired couples like this one. Being cavity nesters, these migrating ducks are headed no further north than southern Canada, to lakes and ponds within forests, for the summer.Harlequin Ducks (Histrionicus histrionicus) spend the summer nesting on turbulent high-gradient streams in Canada and Greenland. They mostly winter along rocky coastlines as far south as New England, but have adapted to feeding along man-made rock jetties in coastal New York and New Jersey. This winter, they were seen along jetties and sea walls at least as far south as Cape Charles, Virginia, and the mouth of Chesapeake Bay. During the past month, at least two Harlequin Ducks, including this male seen in flight on Saturday, have appeared on the river in the Harrisburg area, possibly as strays from this year’s wintering population at the mouth of the bay. These ducks are very rare habitat specialists, possibly (according to Behrens and Cox, 2013) numbering less than 1,500 birds along the entire east coast.In spring, the Horned Grebe transitions from a drab gray-brown winter (basic) plumage into rather surprisingly colorful breeding (alternate) plumage.An adult Horned Grebe in breeding (alternate) plumage. Horned Grebes spend the winter on large rivers, bays, and ocean waters from Nova Scotia to Texas. They are presently on their way to breeding areas on ponds and lakes in Alaska and Canada west of Ontario.
If you want a chance to see these seldom-observed visitors to the lower Susquehanna at Pennsylvania’s capital city, try a morning walk along mid-town’s Riverfront Park from Maclay Street to Forster Street. Also, try a stroll on City Island, particularly to the beach at the north end where you have a view of the mid-river areas upstream. To have better afternoon light, try the river’s west shore along Front Street in Wormleysburg from the Market Street Bridge upstream to Conodoguinet Creek. Once there, be certain to check the river from the Pennsylvania Fish and Boat Commission’s West Fairview Access Area at the mouth of the creek. And don’t be afraid to visit on a gloomy day; you never know what you might find!
Don’t forget to check the trees along the river shoreline where early stonefly hatches can often attract hungry insectivores. We found this and six other Eastern Phoebes crowded into the trees at water’s edge just upriver from the Governor’s Mansion during Saturday’s migrant fallout.
SOURCES
Behrens, Ken, and Cameron Cox. 2013. Seawatching: Eastern Waterbirds in Flight. Houghton Mifflin Harcourt Publishing Company. New York, NY.
