Big Bluestem – LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED

August 4, 2022August 11, 2022

Photo(s) of the Day

A tallgrass prairie wildflower and warm-season grass planting: Big Bluestem — This tallgrass prairie wildflower planting on a health campus in Hershey, Pennsylvania, enhances stormwater management and benefits butterflies and other wildlife. Reducing the acreage maintained as manicured lawn has helped disperse the large flocks of resident Canada Geese (a population of invasive native transplants) that frequented the property and posed a serious hazard to medevac helicopters flying in and out of the facility.

A tallgrass prairie wildflower and warm-season grass planting — Big Bluestem, a warm-season grass, dominates the site and is complemented by Indiangrass and tall wildflowers including Common Milkweed, Wild Bergamot, Oxeye, Black-eyed Susan, Prairie Coneflower, and Purple Coneflower.

November 4, 2021November 4, 2021

A Visit to Bombay Hook National Wildlife Refuge

It’s surprising how many millions of people travel the busy coastal routes of Delaware each year to leave the traffic congestion and hectic life of the northeast corridor behind to visit congested hectic shore towns like Rehobeth Beach, Bethany Beach, and Ocean City, Maryland. They call it a vacation, or a holiday, or a weekend, and it’s exhausting. What’s amazing is how many of them drive right by a breathtaking national treasure located along Delaware Bay just east of the city of Dover—and never know it. A short detour on your route will take you there. It’s Bombay Hook National Wildlife Refuge, a quiet but spectacular place that draws few crowds of tourists, but lots of birds and other wildlife.

Bombay Hook National Wildlife Refuge is located just off Route 9, a lightly-traveled coastal road east of Dover, Delaware. Note the Big Bluestem and other warm season grasses in the background. Bombay Hook, like other refuges in the system, is managed for the benefit of the wildlife that relies upon it to survive. Within recent years, most of the mowed grass and tilled ground that once occurred here has been replaced by prairie grasses or successional growth, much to the delight of Northern Bobwhite (Colinus virginianus) and other species.

Let’s join Uncle Tyler Dyer and have a look around Bombay Hook. He’s got his duck stamp and he’s ready to go.

Uncle Ty’s current United States Fish and Wildlife Service Duck Stamp displayed on his dashboard is free admission to the tour road at Bombay Hook and other National Wildlife Refuges.

The refuge at Bombay Hook includes woodlands, grasslands, and man-made freshwater impoundments, but it is largely comprised of thousands of acres of tidal salt marsh bordering and purifying the waters of Delaware Bay. These marshes are renowned wintering areas for an Atlantic population of Snow Goose known as the “Greater Snow Goose” (Anser caerulescens atlanticus). Thousands of these birds rising over the marsh into the glowing light of a setting sun is an unforgettable sight.

Trails at various stops along the auto tour route lead to observation towers and other features. This boardwalk meanders into the salt marsh grasses and includes a viewing area alongside a tidal creek. Our visit coincided with a very high tide induced by east winds and a new moon.

During high tide, an Eastern Cottontail (Sylvilagus floridanus) seeks higher ground near the boardwalk and the wooded edge of the salt marsh.

As the tide rises, fast-flying shorebirds scramble from flooded mudflats in the salt marsh on the east side of the tour road.

When high tide arrives in the salt marshes, shorebirds and waterfowl often concentrate in the man-made freshwater pools on the west side of the tour road. Glaring afternoon sun is not the best for viewing birds located west of the road. For ideal light conditions, time your visit for a day when high tide occurs in the morning and recedes to low tide in the afternoon.

A view looking west into Shearness Pool, largest of the freshwater impoundments at Bombay Hook.

Bombay Hook has many secretive birds hiding in its wetlands, but they can often be located by the patient observer. Here, two Pied-billed Grebes feed in an opening among the vegetation in a freshwater pool.

One of Bombay Hook’s resident Bald Eagles patrols the wetlands.

American Avocets (Recurvirostra americana) gather by the hundreds at Bombay Hook during the fall. A passing eagle will stir them into flight.

An American Avocet, a delicate wader with a peculiar upturned bill.

As soon as the tide begins receding, shorebirds and waterfowl like these Green-winged Teal begin dispersing into the salt marshes to feed on the exposed mudflats.

The woodlands and forested areas of the refuge host resident songbirds and can be attractive to migrating species like this Yellow-rumped Warbler.

For much of its course, the tour road at Bombay Hook is located atop the dike that creates the man-made freshwater pools on the western edge of the tidal salt marsh. If you drive slowly and make frequent stops to look and listen, you’ll notice an abundance of birds and other wildlife living along this border between two habitats. Here, a Swamp Sparrow has a look around.

Savannah Sparrows are common along the tour road where native grasses grow wild.

Bombay Hook is renowned for its rarities. One of the attractions during the late summer and autumn of 2021 was a group of Roseate Spoonbills (Platalea ajaja), vagrants from the southern states, seen here with Great Egrets and Snowy Egrets (Egretta thula).

Roseate Spoonbills and Great Egrets at Bombay Hook.

Remember to go the Post Office and get your duck stamp. You’ll be supporting habitat acquisition and improvements for the wildlife we cherish. And if you get the chance, visit a National Wildlife Refuge. November can be a great time to go, it’s bug-free! Just take along your warmest clothing and plan to spend the day. You won’t regret it.

September 11, 2020September 11, 2020

Bird Migration Highlights

The southbound bird migration of 2020 is well underway. With passage of a cold front coming within the next 48 hours, the days ahead should provide an abundance of viewing opportunities.

Here are some of the species moving through the lower Susquehanna valley right now.

Blue-winged Teal are among the earliest of the waterfowl to begin southward migration.

Sandpipers and plovers have been on the move since July. The bird in the foreground with these Killdeer is not one of their offspring, but rather a Semipalmated Plover (Charadrius semipalmatus), a regular late-summer migrant in the Lower Susquehanna River Watershed.

Hawk watch sites all over North America are counting birds right now. The Osprey is an early-season delight as it glides past the lookouts. Look for them moving down the Susquehanna as well.

Bald Eagles will be on the move through December. To see these huge raptors in numbers, visit a hawk watch on a day following passage of a cold front when northwest winds are gusting.

Merlins were seen during this past week in areas with good concentrations of dragonflies. This particular one at Middle Creek Wildlife Management Area in Lancaster and Lebanon Counties…

Check the forest canopy for Yellow-billed Cuckoos. Some local birds are still on breeding territories while others from farther north are beginning to move through.

Ruby-throated Hummingbirds are darting through the lower Susquehanna valley on their way to the tropics. This one has no trouble keeping pace with a passing Tree Swallow.

Nocturnal flights can bring new songbirds to good habitat each morning. It’s the best time of year to see numbers of Empidonax flycatchers. But, because they’re often silent during fall migration, it’s not the best time of year to easily identify them. This one lacking a prominent eye ring is a Willow Flycatcher (Empidonax traillii).

During the past two weeks, Red-eyed Vireos have been numerous in many Susquehanna valley woodlands. Many are migrants while others are breeding pairs tending late-season broods.

During mornings that follow heavy overnight flights, Blackburnian Warblers have been common among waves of feeding songbirds.

Chestnut-sided Warblers are regular among flocks of nocturnal migrants seen foraging among foliage at sunrise.

Scarlet Tanagers, minus the brilliant red breeding plumage of the males, are on their way back to the tropics for winter.

While passing overhead on their way south, Bobolinks can be seen or heard from almost anywhere in the lower Susquehanna valley. Their movements peak in late August and early September.

During recent evenings, Bobolinks have been gathering by the hundreds in fields of warm-season grasses at Middle Creek Wildlife Management Area.

If you go to see the Bobolinks there, visit Stop 3 on the tour route late in the afternoon and listen for their call. You’ll soon notice their wings glistening in the light of the setting sun as they take short flights from point to point while they feed. Note the abundance of flying insects above the Big Bluestem and Indiangrass in this image. Grasslands like these are essential habitats for many of our least common resident and migratory birds.

August 31, 2018August 15, 2022

Noxious Benefactor

It’s sprayed with herbicides. It’s mowed and mangled. It’s ground to shreds with noisy weed-trimmers. It’s scorned and maligned. It’s been targeted for elimination by some governments because it’s undesirable and “noxious”. And it has that four letter word in its name which dooms the fate of any plant that possesses it. It’s the Common Milkweed, and it’s the center of activity in my garden at this time of year. Yep, I said milk-WEED.

Now, you need to understand that my garden is small—less than 2,500 square feet. There is no lawn, and there will be no lawn. I’ll have nothing to do with the lawn nonsense. Those of you who know me, know that the lawn, or anything that looks like lawn, and I are through.

Anyway, most of the plants in the garden are native species. There are trees, numerous shrubs, some water features with aquatic plants, and filling the sunny margins is a mix of native grassland plants including Common Milkweed. The unusually wet growing season in 2018 has been very kind to these plants. They are still very green and lush. And the animals that rely on them are having a banner year. Have a look…

The flowers of the Common Milkweed were exceptionally fragrant this year. At their peak in early June, their hyacinth-or lilac-like aroma was so prevalent, it drifted into the house and overwhelmed the stink of the neighbor’s filthy dumpster that he had placed 12 feet away from my walls (100 feet from his).

Common Milkweed attracts a pollinating Greenbottle Fly (Lucilia species). The dumpster attracts the invasive House Fly (Musca domestica), carrier of dysentery, typhoid, and other wonderful diseases. Are you following this? Remember as we proceed, milkweed is noxious.

Busy Eastern Carpenter Bees (Xylocopa virginica) load up with pollen from the flowers of the Common Milkweed.

A Red Milkweed Beetle (Tetraopes tetrophthalmus) munches on a tender fresh Common Milkweed leaf in mid-June.

Following the pollination of the flowers, seed pods will begin to grow. I trim these off the plants. The removal of the extra weight allows most of the stems to remain erect through stormy weather. You’ll still get new plants from underground runners. As you may have guessed, I’m trying to keep these plants upright and strong to host Monarch butterfly larvae.

I’ve planted a variety of native grassland species to help support the milkweed structurally and to provide a more complete habitat for Monarch butterflies and other native insects. This year, these plants are exceptionally colorful for late-August due to the abundance of rain. The warm season grasses shown below are the four primary species found in the American tall-grass prairies and elsewhere.

Big Bluestem, a native warm-season grass in flower.

Little Bluestem (Schizachyrium scoparium “Fort Indiantown Gap”) in flower. This variety grows on the tank range at the military base where the armored vehicles and prescribed burns substitute for the herd animals and fires of the prairie to prevent succession and allow it to thrive.

Partridge Pea can tolerate sandy soil and is a host plant for vagrant Cloudless Sulphur butterflies.

Black-eyed Susan (Rudbeckia hirta) is a popular native grassland wildflower.

Indiangrass (Sorghastrum nutans) in flower. This and the other native plants shown here are available as seed from Ernst Seed Company in Meadville (PA). They have an unbelievably large selection of indigenous species. You can plant a small plot or acres and acres using really good mixes blended for purposes ranging from reclaiming pipeline right-of-ways and strip mines to naturalizing backyard gardens.

A Red Admiral (Vanessa atalanta) butterfly, a migratory species like the Monarch, on Purple Coneflower (Echinacea purpurea). Yes, it is that Echinacea.

There was Monarch activity in the garden today like I’ve never seen before—and it revolved around milkweed and the companion plants.

A female Monarch laying eggs on a Common Milkweed leaf.

A third instar Monarch caterpillar with Oleander Aphids (Aphis nerii) on a Common Milkweed leaf. Both of these insect species absorb toxins from the milkweed which makes them distasteful to predators.

Fifth instar (left and center) and fourth instar (right) monarch caterpillars devour a Common Milkweed leaf. There were over thirty of these caterpillars in just a ten by ten feet area this morning. I hope if you’re keeping a habitat for Monarchs, you’re enjoying the same fortune right now!

A slow-moving Monarch stopped for a break after making the circuit to deposit eggs on milkweed throughout the garden.

Third instar (top), fourth instar (right), and fifth instar (left) Monarch caterpillars quickly consume the leaf of a Common Milkweed plant. Caterpillars emerging from eggs deposited today may not have sufficient late-season food to complete the larval segment of their life cycle. Need more milkweed!

After benefitting from the nourishment of the Common Milkweed plant, a fifth instar Monarch caterpillar begins pupation on Big Bluestem grass.

Two hours later, the chrysalis is complete.

Another chrysalis, this one on flowering Switchgrass just two feet away from the previous one. An adult Monarch will emerge from this pupa to become part of what we hope will be the most populated southbound exodus for the species in over five years.

There it is, soon ready to fly away. And all courtesy of the noxious milkweed.

A chrysalis can often be found on man-made objects too. This one is on the rim of a flower pot.

Ornamental flowers can attract adult Monarch butterflies seeking nectar. I am now more careful to select seeds and plants that have not been treated with neonicotinoid insecticides. There’s growing concern over the impact these compounds may be having on pollinating species of animals. Oh…and I don’t mow, whack, cut, mutilate, or spray herbicides on my milkweed But you probably figured that out already.

SOURCES

Eaton, Eric R., and Kenn Kaufman. 2007. Kaufman Field Guide to Insects of North America. Houghton Mifflin Company. New York.

February 17, 2018February 17, 2018

A Flock of Seagulls?

At the moment there is a heavy snow falling, not an unusual occurrence for mid-February, nevertheless, it is a change in weather. Forty-eight hours ago we were in the midst of a steady rain and temperatures were in the sixties. The snow and ice had melted away and a touch of spring was in the air.

Big Bluestem in the Riverine Grasslands is inundated by the rising waters of the Susquehanna at Conewago Falls. The river ice has been dispersed by the recent mild temperatures and rains.

Anyone casually looking about while outdoors during these last several days may have noticed that birds are indeed beginning to migrate north in the lower Susquehanna valley. Killdeer, American Robins, Eastern Bluebirds, Red-winged Blackbirds, and Common Grackles are easily seen or heard in most of the area now.

Just hours ago, between nine o’clock this morning and one o’clock this afternoon, there was a spectacular flight of birds following the river north, their spring migration well underway. In the blue skies above Conewago Falls, a steady parade of Ring-billed Gulls was utilizing thermals and riding a tailwind from the south-southeast to cruise high overhead on a course toward their breeding range.

Ring-billed Gulls swarm in a thermal updraft above Conewago Falls to gain altitude prior to streaming off to the north and continuing their journey.

Ring-billed Gulls climbing to heights sometimes exceeding 1,000 feet before breaking off and gliding away to the north.

The swirling hoards of Ring-billed Gulls attracted other migrants to take advantage of the thermals and glide paths on the breeze. Right among them were 44 Herring Gulls, 3 Great Black-backed Gulls, 12 Tundra Swans (Cygnus columbianus), 10 Canada Geese, 3 Northern Pintails (Anas acuta), 6 Common Mergansers, 3 Red-tailed Hawks, a Red-shouldered Hawk, 6 Bald Eagles (non-adults), 8 Black Vultures, and 5 Turkey Vultures.

A first-year Herring Gull (top center) is a standout in a “kettle” of Ring-billed Gulls.

How many Ring-billed Gulls passed by today? More than 18,000…with emphasis on **MORE THAN**. You see, early this afternoon, the handy-dandy clicker-counter used to tick off and tally the big flights of birds as they pass by quit clicking and counting. Therefore, 18,000 is the absolute minimum number of Ring-billed Gulls seen migrating north today. Hopefully the trusty old oil can will get the clicker working again soon.

In the afternoon, the clouds closed in quickly, the flight ended, and by dusk more than an inch of snow was on the ground. Looks like spring to me.

August 16, 2017September 4, 2019

S’more

The tall seed-topped stems swaying in a summer breeze are a pleasant scene. And the colorful autumn shades of blue, orange, purple, red, and, of course, green leaves on these clumping plants are nice. But of the multitude of flowering plants, Big Bluestem, Freshwater Cordgrass, and Switchgrass aren’t much of a draw. No self-respecting bloom addict is going out of their way to have a gander at any grass that hasn’t been subjugated and tamed by a hideous set of spinning steel blades. Grass flowers…are you kidding?

Big Bluestem in flower in the Riverine Grasslands at Conewago Falls.

O.K., so you need something more. Here’s more.

Meet the Partridge Pea (Chamaecrista fasciculata). It’s an annual plant growing in the Riverine Grasslands at Conewago Falls as a companion to Big Bluestem. It has a special niche growing in the sandy and, in summertime, dry soils left behind by earlier flooding and ice scour. The divided leaves close upon contact and also at nightfall. Bees and other pollinators are drawn to the abundance of butter-yellow blossoms. Like the familiar pea of the vegetable garden, the flowers are followed by flat seed pods.

The Partridge Pea can tolerate dry sandy soils.

But wait, here’s more.

In addition to its abundance in Conewago Falls, the Halberd-leaved Rose Mallow (Hibiscus laevis) is the ubiquitous water’s edge plant along the free-flowing Susquehanna River for miles downstream. It grows in large clumps, often defining the border between the emergent zone and shore-rooted plants. It is particularly successful in accumulations of alluvium interspersed with heavier pebbles and stone into which the roots will anchor to endure flooding and scour. Such substrate buildup around the falls, along mid-river islands, and along the shores of the low-lying Riparian Woodlands immediately below the falls are often quite hospitable to the species.

Halberd-leaved Rose Mallow is a durable inhabitant of the falls. Regular flooding keeps competing species at bay. A taproot helps to safeguard against dislocation, allowing plants to grow in places subjected to turbulent currents.

Halberd-leaved Rose Mallow in bloom. The similarity to cultivated members of the *Hibiscus* genus can readily be seen. It is one of the showiest of perennial wildflowers in the floodplain. Note the lobed, halberd-shaped leaves, source of its former species name *militaris*.

The seeds of Halberd-leaved Rose Mallow are contained in bladders which can float to assist in their distribution. Some of these bladders cling to the dead leafless stems in winter, making it an easy plant to identify in nearly any season.

A second native wildflower species in the genus Hibiscus is found in the Conewago Falls floodplain, this one in wetlands. The Swamp Rose Mallow (H. moscheutos) is similar to Halberd-leaved Rose Mallow, but sports more variable and colorful blooms. The leaves are toothed without the deep halberd-style lobes and, like the stems, are downy. As the common name implies, it requires swampy habitat with ample water and sunlight.

Swamp Rose Mallow in a sunny wetland. This variety with solid-colored flowers (without dark centers) and pale green leaves and stems was formerly known as a separate species of Swamp Rose Mallow, *H. palustris*. Note that the flowers are terminal on the stems.

A few scattered specimens of a more typical variety of Swamp Rose Mallow are found on the shoreline and in the Riverine Grasslands of Conewago Falls. The blooms are bright pink with darker centers and the leaf stems are robust and reddish. This one is seen growing among Halberd-leaved Rose Mallow, with which it shares the characteristic of having flower stems growing from some of the upper leaf axils. A variety with red-centered white flowers is often found throughout the plant’s range.

In summary, we find Partridge Pea in the Riverine Grasslands growing in sandy deposits left by flood and ice scour. We find Halberd-leaved Rose Mallow rooted at the border between shore and the emergent zone. We find Swamp Rose Mallow as an emergent in the wetlands of the floodplain. And finally, we find marshmallows in only one location in the area of Conewago Falls. Bon ap’.

SOURCES

Newcomb, Lawrence. 1977. Newcomb’s Wildflower Guide. Little, Brown and Company. Boston, Massachusetts.

August 14, 2017September 4, 2019

Summer Grasses

It has not been a good summer if you happen to be a submerged plant species in the lower Susquehanna River. Regularly occurring showers and thunderstorms have produced torrents of rain and higher than usual river stages. The high water alone wouldn’t prevent you from growing, colonizing a wider area, and floating several small flowers on the surface, however, the turbidity, the suspended sediment, would. The muddy current casts a dirty shadow on the benthic zone preventing bottom-rooted plants from getting much headway. There will be smaller floating mats of the uppermost leaves of these species. Fish and invertebrates which rely upon this habitat for food and shelter will find sparse accommodation…better luck next year.

Due to the dirty water, fish-eating birds are having a challenging season as they try to catch sufficient quantities of prey to feed themselves and their offspring. A family of Ospreys (Pandion haliaetus) at Conewago Falls, including recently fledged young, were observed throughout this morning and had no successful catches. Of the hundred or more individual piscivores of various species present, none were seen retrieving fish from the river. The visibility in the water column needs to improve before fishing is a viable enterprise again.

Ospreys competing for a suitable fishing perch. Improving water conditions in the coming week should increase their success as predators.

Versatile at finding food, adult Bald Eagles are experienced and know to be on the lookout for Ospreys with fish, a meal they can steal through intimidation.

While the submerged plant communities may be stunted by 2017’s extraordinary water levels, there is a very unique habitat in Conewago Falls which endures summer flooding and, in addition, requires the scouring effects of river ice to maintain its mosaic of unique plants. It is known as a Riverine Grassland or scour grassland.

The predominant plants of the Riverine Grasslands are perennial warm-season grasses. The deep root systems of these hardy species have evolved to survive events which prevent the grassland from reverting to woodland through succession. Fire, intense grazing by wild herd animals, poor soils, drought, and other hardships, including flooding and ice scour, will eliminate intolerant plant species and prevent an area from reforesting. In winter and early spring, scraping and grinding by flood-driven chunk ice mechanically removes large woody and poorly rooted herbaceous growth from susceptible portions of the falls. These adverse conditions clear the way for populations of species more often associated with North America’s tall grass prairies to take root. Let’s have a look at some of the common species found in the “Conewago Falls Pothole Rocks Prairie”.