A Limpkin’s Journey to Pennsylvania: A Waffle House Serving Escargot at Every Exit
Mid-summer can be a less than exciting time for those who like to observe wild birds. The songs of spring gradually grow silent as young birds leave the nest and preoccupy their parents with the chore of gathering enough food to satisfy their ballooning appetites. To avoid predators, roving families of many species remain hidden and as inconspicuous as possible while the young birds learn how to find food and handle the dangers of the world.
But all is not lost. There are two opportunities for seeing unique birds during the hot and humid days of July.
First, many shorebirds such as sandpipers, plovers, dowitchers, and godwits begin moving south from breeding grounds in Canada. That’s right, fall migration starts during the first days of summer, right where spring migration left off. The earliest arrivals are primarily birds that for one reason on another (age, weather, food availability) did not nest this year. These individuals will be followed by birds that completed their breeding cycles early or experienced nest failures. Finally, adults and juveniles from successful nests are on their way to the wintering grounds, extending the movement into the months we more traditionally start to associate with fall migration—late August into October.
For those of you who find identifying shorebirds more of a labor than a pleasure, I get it. For you, July can bring a special treat—post-breeding wanderers. Post-breeding wanderers are birds we find roaming in directions other than south during the summer months, after the nesting cycle is complete. This behavior is known as “post-breeding dispersal”. Even though we often have no way of telling for sure that a wandering bird did indeed begin its roving journey after either being a parent or a fledgling during the preceding nesting season, the term post-breeding wanderer still applies. It’s a title based more on a bird sighting and it’s time and place than upon the life cycle of the bird(s) being observed. Post-breeding wanderers are often southern species that show up hundreds of miles outside there usual range, sometimes traveling in groups and lingering in an adopted area until the cooler weather of fall finally prompts them to go back home. Many are birds associated with aquatic habitats such as shores, marshes, and rivers, so water levels and their impact on the birds’ food supplies within their home range may be the motivation for some of these movements. What makes post-breeding wanderers a favorite among many birders is their pop. They are often some of our largest, most colorful, or most sought-after species. Birds such as herons, egrets, ibises, spoonbills, stilts, avocets, terns, and raptors are showy and attract a crowd.
While it’s often impossible to predict exactly which species, if any, will disperse from their typical breeding range in a significant way during a given year, some seem to roam with regularity. Perhaps the most consistent and certainly the earliest post-breeding wanderer to visit our region is the “Florida Bald Eagle”. Bald Eagles nest in “The Sunshine State” beginning in the fall, so by early spring, many of their young are on their own. By mid-spring, many of these eagles begin cruising north, some passing into the lower Susquehanna valley and beyond. Gatherings of dozens of adult Bald Eagles at Conowingo Dam during April and May, while our local adults are nesting and after the wintering birds have gone north, probably include numerous post-breeding wanderers from Florida and other Gulf Coast States.
So this week, what exactly was it that prompted hundreds of birders to travel to Middle Creek Wildlife Management Area from all over the Mid-Atlantic States and from as far away as Colorado?
Was it the majestic Great Blue Herons and playful Killdeer?
Was it the colorful Green Herons?
Was it the Great Egrets snapping small fish from the shallows?
Was it the small flocks of shorebirds like these Least Sandpipers beginning to trickle south from Canada?
All very nice, but not the inspiration for traveling hundreds or even thousands of miles to see a bird.
It was the appearance of this very rare post-breeding wanderer…
…Pennsylvania’s first record of a Limpkin, a tropical wading bird native to Florida, the Caribbean Islands, and South America. Many observers visiting Middle Creek Wildlife Management Area had never seen one before, so if they happen to be a “lister”, a birder who keeps a tally of the wild bird species they’ve seen, this Limpkin was a “lifer”.
The Limpkin is an inhabitant of vegetated marshlands where it feeds almost exclusively upon large snails of the family Ampullariidae, including the Florida Applesnail (Pomacea paludosa), the largest native freshwater snail in the United States.
Observations of the Limpkin lingering at Middle Creek Wildlife Management Area have revealed a pair of interesting facts. First, in the absence of Florida Applesnails, this particular Limpkin has found a substitute food source, the non-native Chinese Mystery Snail (Cipangopaludina chinensis). And second, Chinese Mystery Snails have recently become established in the lakes, pools, and ponds at the refuge, very likely arriving as stowaways on Spatterdock (Nuphar advena) and/or American Lotus (Nelumbo lutea), native transplants brought in during recent years to improve wetland habitat and process the abundance of nutrients (including waterfowl waste) in the water.
The Middle Creek Limpkin’s affinity for Chinese Mystery Snails may help explain how it was able to find its way to Pennsylvania in apparent good health. Look again at the map showing the range of the Limpkin’s primary native food source, the Florida Applesnail. Note that there are established populations (shown in brown) where these snails were introduced along the northern coast of Georgia and southern coast of South Carolina…
…now look at the latest U.S.G.S. Nonindigenous Aquatic Species map showing the ranges (in brown) of established populations of non-native Chinese Mystery Snails…
…and now imagine that you’re a happy-go-lucky Limpkin working your way up the Atlantic Coastal Plain toward Pennsylvania and taking advantage of the abundance of food and sunshine that summer brings to the northern latitudes. It’s a new frontier. Introduced populations of Chinese Mystery Snails are like having a Waffle House serving escargot at every exit along the way!
Be sure to click the “Freshwater Snails” tab at the top of this page to learn more about the Chinese Mystery Snail and its arrival in the Lower Susquehanna River Watershed. Once there, you’ll find some additional commentary about the Limpkin and the likelihood of Everglade Snail Kites taking advantage of the presence of Chinese Mystery Snails to wander north. Be certain to check it out.
Photo of the Day
Hey, Let’s Go to Conowingo: It’s Bald Eagle Time
Why are there dozens of people with enormous lenses on complicated cameras atop sturdy tripods gathered at Fisherman’s Park below the Conowingo Dam on the lower Susquehanna River in Maryland? It’s Bald Eagle time, that’s why. Here are some photos from the scene, taken just two days ago.
To reach Exelon Energy’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road. Drive down the hill to the parking area along the river. The park’s address is 2569 Shureslanding Road, Darlington, Maryland.
Do make an excursion to the lower Susquehanna at Conowingo soon. To avoid crowds and parking congestion, plan to visit on a weekday. You’ll want warm clothing, binoculars, and a camera too.
Conowingo Dam: Cormorants, Eagles, Snakeheads and a Run of Hickory Shad
Meet the Double-crested Cormorant, a strangely handsome bird with a special talent for catching fish. You see, cormorants are superb swimmers when under water—using their webbed feet to propel and maneuver themselves with exceptional speed in pursuit of prey.
Double-crested Cormorants, hundreds of them, are presently gathered along with several other species of piscivorous (fish-eating) birds on the lower Susquehanna River below Conowingo Dam near Rising Sun, Maryland. Fish are coming up the river and these birds are taking advantage of their concentrations on the downstream side of the impoundment to provide food to fuel their migration or, in some cases, to feed their young.
In addition to the birds, the movements of fish attract larger fish, and even larger fishermen.
The excitement starts when the sirens start to wail and the red lights begin flashing. Yes friends, it’s showtime.
Within minutes of the renewed flow, birds are catching fish.
Then the anglers along the wave-washed shoreline began catching fish too.
The arrival of migrating Hickory Shad heralds the start of a movement that will soon include White Perch, anadromous American Shad, and dozens of other fish species that swim upstream during the springtime. Do visit Fisherman’s Park at Conowingo Dam to see this spectacle before it’s gone. The fish and birds have no time to waste, they’ll soon be moving on.
To reach Exelon’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road. Drive down the hill to the parking area along the river. The park’s address is 2569 Shureslanding Road, Darlington, Maryland.
A water release schedule for the Conowingo Dam can be obtained by calling Exelon Energy’s Conowingo Generation Hotline at 888-457-4076. The recording is updated daily at 5 P.M. to provide information for the following day.
And remember, the park can get crowded during the weekends, so consider a weekday visit.
Bald Eagles Arriving at Conowingo Dam
You need to see this to believe it—dozens, sometimes hundreds, of Bald Eagles doing their thing and you can stand or sit in just one place to take it all in.
Conowingo Dam on the Susquehanna River near Darlington, Maryland, attracts piscivores galore. Young Gizzard Shad (Dorosoma cepedianum) and other small fishes are temporarily stunned as they pass through the turbines and gated discharges at the hydroelectric facility’s power house. Waiting for them in the rapids below are predatory fishes including Striped Bass (Morone saxatilis), White Perch (Morone americana), several species of catfishes, and more. From above, fish-eating birds are on the alert for a disoriented turbine-traveler they can easily seize for a quick meal.
To reach Exelon’s Conowingo Fisherman’s Park from Rising Sun, Maryland, follow U.S. Route 1 south across the Conowingo Dam, then turn left onto Shuresville Road, then make a sharp left onto Shureslanding Road. Drive down the hill to the parking area along the river. The park’s address is 2569 Shureslanding Road, Darlington, Maryland.
As Bald Eagle numbers continue to increase, expect the parking lot to become full during weekends and over the Thanksgiving holiday. To avoid the crowds, plan to visit during a weekday.
You can get the generating schedule for the Conowingo Dam by calling the Conowingo Generation Hotline at 888-457-4076. The recording is updated daily at 5 P.M. to provide information for the following day.
Shocking Fish Photos!
There are two Conewago Creek systems in the Lower Susquehanna River Watershed. One drains the Gettysburg Basin west of the river, mostly in Adams and York Counties, then flows into the Susquehanna at the base of Conewago Falls. The other drains the Gettysburg Basin east of the river, flowing through Triassic redbeds of the Gettysburg Formation and York Haven Diabase before entering Conewago Falls near the south tip of Three Mile Island. Both Conewago Creeks flow through suburbia, farm, and forest. Both have their capacity to support aquatic life impaired and diminished by nutrient and sediment pollution.
This week, some of the many partners engaged in a long-term collaboration to restore the east shore’s Conewago Creek met to have a look at one of the prime indicators of overall stream habitat health—the fishes. Kristen Kyler of the Lower Susquehanna Initiative organized the effort. Portable backpack-mounted electrofishing units and nets were used by crews to capture, identify, and count the native and non-native fishes at sampling locations which have remained constant since prior to the numerous stream improvement projects which began more than ten years ago. Some of the present-day sample sites were first used following Hurricane Agnes in 1972 by Stambaugh and Denoncourt and pre-date any implementation of sediment and nutrient mitigation practices like cover crops, no-till farming, field terracing, stormwater control, nutrient management, wetland restoration, streambank fencing, renewed forested stream buffers, or modernized wastewater treatment plants. By comparing more recent surveys with this baseline data, it may be possible to discern trends in fish populations resulting not only from conservation practices, but from many other variables which may impact the Conewago Creek Warmwater Stream ecosystem in Dauphin, Lancaster, and Lebanon Counties.
So here they are. Enjoy these shocking fish photos.
SOURCES
Normandeau Associates, Inc. and Gomez and Sullivan. 2018. Muddy Run Pumped Storage Project Conowingo Eel Collection Facility FERC Project 2355. Prepared for Exelon.
Stambaugh, Jr., John W., and Robert P. Denoncourt. 1974. A Preliminary Report on the Conewago Creek Faunal Survey, Lancaster County, Pennsylvania. Proceedings of the Pennsylvania Academy of Sciences. 48: 55-60.