Shorebirds at Middle Creek

Late August and early September is prime time to see migrating shorebirds as they pass through the lower Susquehanna valley during their autumn migration, which, believe it or not, can begin as early as late June.  These species that are often assumed to spend their lives only near the seashore are regular visitors each fall as they make their way from breeding grounds in the interior of Canada to wintering sites in seacoast wetlands—many traveling as far south as Central and South America.

Low water levels on the Susquehanna River often coincide with the shorebird migration each year, exposing gravel and sand bars as well as vast expanses of muddy shorelines as feeding and resting areas for these traveling birds.  This week though, rain from the remnants of Tropical Storm Fred arrived to increase the flow in the Susquehanna and inundate most of the natural habitat for shorebirds.  Those on the move must either continue through the area without stopping or find alternate locations to loaf and find food.

The draining and filling of wetlands along the river and elsewhere in the region has left few naturally-occurring options.  The Conejohela Flats south of Columbia offer refuge to many migrating sandpipers and their allies, the river level there being controlled by releases from the Safe Harbor Dam during all but the severest of floods.  Shorebirds will sometimes visit flooded fields, but wide-open puddles and farmland resembling mudflats is more of springtime occurrence—preceding the planting and growth of crops.  Well-designed stormwater holding facilities can function as habitat for sandpipers and other wildlife.  They are worth checking on a regular basis—you never know what might drop in.

Right now, there is a new shorebird hot spot in the Lower Susquehanna River Watershed—Middle Creek Wildlife Management Area.  The water level in the main impoundment there has been drawn down during recent weeks to expose mudflats along the periphery of nearly the entire lake.  Viewing from “Stop 1” (the roadside section of the lake in front of the refuge museum) is best.  The variety of species and their numbers can change throughout the day as birds filter in and out—at times traveling to other mudflats around the lake where they are hidden from view.  The birds at “Stop 1” are backlit in the morning with favorable illumination developing in the afternoon.

Have a look at a few of the shorebirds currently being seen at Middle Creek…

The Killdeer is familiar as a breeding bird in the lower Susquehanna region.  Large numbers can congregate ahead of and during migration on mudflats and gravel bars.
The Least Sandpiper is one of the “peeps”, a group of very small shorebirds.  This species is quite common at Middle Creek right now.  Note the plants beginning to grow in the mud.  Later in the fall, after the shorebirds are gone, raising the water level in the lake will flood these newly vegetated areas to provide an abundance of food for migrating waterfowl.  This cycle can be repeated annually to support transient birds during what is often the most vulnerable time of their lives…fall migration.
The Baird’s Sandpiper (Calidris bairdii) is an uncommon “peep” along the east coast during autumn migration.  On the lower Susquehanna it is most frequently encountered on the vegetated gravel bars in mid-river during the last days of August or first days of September each year.  The mudflats and shallows at Middle Creek are providing a suitable alternative for this juvenile bird.
Numbers of Lesser Yellowlegs are increasing as flocks drop by for a rest and refueling.  Bring your binoculars and your spotting scope to see the oddities that may be hiding among these groups of newly-arriving migrants.

The aquatic environs at Middle Creek attract other species as well.   Here are some of the most photogenic…

Wood Ducks atop the dam.
The migration of Caspian Terns coincides with that of shorebirds.  Just look at that blood-red bill; it’s unmistakable.  Two of these big terns are currently patrolling Middle Creek’s lake and shoreline.
A female American Kestrel creates a stir among the “peeps” as it passes by.  The larger falcons (the Merlin and Peregrine) can be expected to more readily take advantage of concentrations of shorebirds as a food supply.
Osprey migration is underway, and many will stop at Middle Creek while in transit.
Even if shorebirds aren’t your thing, there are almost always Bald Eagles to be seen at Middle Creek.  See you there!

Summer Breeze

A moderate breeze from the south placed a headwind into the face of migrants trying to wing their way to winter quarters.  The urge to reach their destination overwhelmed any inclination a bird or insect may have had to stay put and try again another day.

Blue Jays were joined by increasing numbers of American Robins crossing the river in small groups to continue their migratory voyages.  Killdeer (Charadrius vociferous) and a handful of sandpipers headed down the river route.  Other migrants today included a Cooper’s Hawk (Accipiter cooperii), Eastern Bluebirds (Sialia sialis), and a few Common Mergansers (Mergus merganser), House Finches (Haemorhous mexicanus), and Common Grackles (Quiscalus quiscula).

The afternoon belonged to the insects.  The warm wind blew scores of Monarchs toward the north as they persistently flapped on a southwest heading.  Many may have actually lost ground today.  Painted Lady (Vanessa cardui) and Cloudless Sulphur butterflies were observed battling their way south as well.  All three of the common migrating dragonflies were seen: Common Green Darner (Anax junius), Wandering Glider (Pantala flavescens), and Black Saddlebags (Tramea lacerata).

The warm weather and summer breeze are expected to continue as the rain and wind from Hurricane Nate, today striking coastal Alabama and Mississippi, progresses toward the Susquehanna River watershed during the coming forty-eight hours.

This Great Blue Heron was joined by numerous other fishermen and a good number of sightseers in the falls today.
A colorful young Northern Water Snake (Nerodia sipedon) takes advantage of the sun-heated surface of a Pothole Rock to remain nimble and active.  Cooler weather will soon compel this and other reptiles to find shelter for winter hibernation.
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Yellowlegs for Breakfast

A few nocturnal migrants flew through the moonlit night to arrive at Conewago Falls for a sunrise showing this morning.  A dozen warblers were in the treetops and a Wood Thrush (Hylocichla mustelina) chattered away in the understory of the Riparian Woodlands.  Three species of shorebirds were in the falls and on the Pothole Rocks: Least Sandpiper (Calidris minutilla), Lesser Yellowlegs (Tringa flavipes), and Greater Yellowlegs (Tringa melanoleuca).

A Greater Yellowlegs (right) and two Lesser Yellowlegs sandpipers dropped by for breakfast.

The diurnal migration was highlighted by a Merlin (Falco columbarius), an Osprey, and a Bald Eagle, each flying down the river.  Most of the other birds in the falls seemed content to linger and feed.  There’s no need to hurry folks, only trouble lurks down there in paradise at the moment.

A light to moderate flight of nocturnal migrants in the eastern United States is displayed on NOAA National Weather Service NEXRAD radar at 4:58 AM EDT.  The eye of Hurricane Irma can be seen approaching the Florida Keys.  (NOAA/National Weather Service image)
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