For many animals, an adequate shelter is paramount for their successful reproduction. Here’s a sample of some of the lower Susquehanna valley’s nest builders in action…





















LIFE IN THE LOWER SUSQUEHANNA RIVER WATERSHED
A Natural History of Conewago Falls—The Waters of Three Mile Island
For many animals, an adequate shelter is paramount for their successful reproduction. Here’s a sample of some of the lower Susquehanna valley’s nest builders in action…




















After repeatedly hearing the songs of these Neotropical migrants from among the foliage, we were finally able to get a look at them—but it required persistent effort.














Sometimes we have to count ourselves lucky if we see just one in five, ten, or even twenty of the birds we hear in the cover of the forest canopy or thicket. But that’s what makes this time of year so rewarding for the dedicated observer. The more time you spend out there, the more you’ll eventually discover. See you afield!


Neotropical birds are fairly well acquainted with repetitive periods of thundershowers. With that in mind, we decided not to waste this stormy Tuesday by remaining indoors.












We hope you enjoyed our walk in the rain as much as we did. If you venture out on a similar excursion, please remember this. The majority of the wild animals around us have busy lives, particularly at this time of year. Most don’t take a day off just because it rains—that includes ticks.

As the Flowering Dogwoods remind us, it’s time for adult sea-run shad and other fishes to ascend the Susquehanna to spawn. So yep, we’re off to Fisherman’s Park on the river’s west shoreline below Conowingo Dam in Harford County, Maryland, to check it out.



























Here’s a look at six native shrubs and trees you can find blooming along forest edges in the lower Susquehanna valley right now.







Local old timers might remember hearing folklore that equates the northward advance of the blooming of the Flowering Dogwoods with the progress of the American Shad’s spring spawning run up the river. While this is hardly a scientific proclamation, it is likely predicated on what had been some rather consistent observation prior to the construction of the lower Susquehanna’s hydroelectric dams. In fact, we’ve found it to be a useful way to remind us that it’s time for a trip to the river shoreline below Conowingo Dam to witness signs of the spring fish migration each year. We’re headed that way now and will summarize our sightings for you in days to come.

Despite what seemed to be a chilly early spring, the bright green leaves that unfold to close the canopy of our deciduous forests were dense and casting shade by the last days of April. For northbound migrants, this fresh foliage provides the cover they need for foraging, resting, and, for those that will stick around to breed in the lower Susquehanna valley, nesting.
We recall many occasions when sparse foliage during the first days of May seemed to delay the big push of Neotropical species, but the seasonal arrival of these birds in 2025 is thus far mostly ahead of schedule. This absence of delay is due in part to the lushness of the oaks. Some stands have not only leafed out, but are finished flowering and have added up to 12 inches of new branch growth. We spent these early hours of May among the oaks. Here’s a look at the Neotropical migrants and other species we found…








The movements of our migratory birds typically continue through much of the month of May. And peak numbers of Neotropical species often occur sometime during the second week of the month. But with habitat at the ready, favorable flight conditions could facilitate quick arrival and/or passage of the bulk of the remaining migrants during the coming week. You may want to venture out sooner rather than later—but watch your step!




Here are five common forest flowers that the average visitor to these environs may easily overlook during an early April visit.





Be certain to get out and enjoy this year’s blooming seasons of our hundreds of varieties of flowering plants. But, particularly when it comes to native species,…
During Saturday’s Prescribed Fire Demonstration at the Pennsylvania Game Commission’s Middle Creek Wildlife Management Area, we noticed just how fast some species of wildlife return to areas subjected to burns administered to maintain grassland habitat and reduce the risk of high-intensity blazes.







Following the Prescribed Fire Demonstration, we decided to pay a visit to some of the parcels where burns had been administered one week earlier on the north side of Middle Creek’s main impoundment. We found a surprising amount of activity.







By late winter, sunshine and warming temperatures awaken the sleeping maples of the lower Susquehanna basin and the sap begins to flow. The new growing season is evident by the first days of spring when their swelling buds and flowers paint the drab gray canopy of deciduous woodlands with an overlying coat of red, orange, and maroon.




Our wildlife has been having a tough winter. The local species not only contend with cold and stormy weather, but they also need to find food and shelter in a landscape that we’ve rendered sterile of these essentials throughout much of the lower Susquehanna valley’s farmlands, suburbs, and cities.
Planting trees, shrubs, flowers, and grasses that benefit our animals can go a long way, often turning a ho-hum parcel of property into a privately owned oasis. Providing places for wildlife to feed, rest, and raise their young can help assure the survival of many of our indigenous species. With a little dedication, you can be liberated from the chore of manicuring a lawn and instead spend your time enjoying the birds, mammals, insects, and other creatures that will visit your custom-made habitat.

Fortunately for us, our local county conservation districts are again conducting springtime tree sales offering a variety of native and beneficial cultivated plants at discount prices. Listed here are links to information on how to pre-order your plants for pickup in April. Click away to check out the species each county is offering in 2025!
Cumberland County Conservation District Annual Tree Seedling Sale—
Orders due by: Friday, March 21, 2025
Pickup on: Thursday, April 24, 2025 or Friday, April 25, 2025

Dauphin County Conservation District Seedling Sale—
Orders due by: Monday, March 17, 2025
Pickup on: Thursday, April 24, 2025 or Friday, April 25, 2025

Franklin County Conservation District Tree Seedling Sale—
Orders due by: Wednesday, March 19, 2025
Pickup on: Thursday, April 24, 2025

Lancaster County Annual Tree Seedling Sale—
Orders due by: Friday, March 7, 2025
Pickup on: Friday, April 11, 2025

Lebanon County Conservation District Tree and Plant Sale—
Orders due by: Monday, March 3, 2025
Pickup on: Friday, April 18, 2025




York County Conservation District Seedling Sale—
Orders due by: March 15, 2025
Pickup on: Thursday, April 10, 2025


If you live in Adams County, Pennsylvania, you may be eligible to receive free trees and shrubs for your property from the Adams County Planting Partnership (Adams County Conservation District and the Watershed Alliance of Adams County). These trees are provided by the Chesapeake Bay Foundation’s Keystone 10-Million Trees Partnership which aims to close a seven-year project in 2025 by realizing the goal of planting 10 million trees to protect streams by stabilizing soils, taking up nutrients, reducing stormwater runoff, and providing shade. If you own property located outside of Adams County, but still within the Chesapeake Bay Watershed (which includes all of the Susquehanna, Juniata, and Potomac River drainages), you still may have an opportunity to get involved. Contact your local county conservation district office or watershed organization for information.


We hope you’re already shopping. Need help making your selections? Click on the “Trees, Shrubs, and Woody Vines” tab at the top of this page to check out Uncle Tyler Dyer’s leaf collection. He has most of the species labelled with their National Wetland Plant List Indicator Rating. You can consult these ratings to help find species suited to the soil moisture on your planting site(s). For example: if your site has sloped upland ground and/or the soils sometimes dry out in summer, select plants with a rating such as UPL or FACU. If your planting in soils that remain moist or wet, select plants with the OBL or FACW rating. Plants rated FAC are generally adaptable and can usually go either way, but may not thrive or survive under stressful conditions in extremely wet or dry soils.
NATIONAL WETLAND PLANT LIST INDICATOR RATING DEFINITIONS
Using these ratings, you might choose to plant Pin Oaks (FACW) and Swamp White Oaks (FACW) in your riparian buffer along a stream; Northern Red Oaks (FACU) and White Oaks (FACU) in the lawn or along the street, driveway, or parking area; and Chestnut Oaks (UPL) on your really dry hillside with shallow soil. Give it a try.
Each spring and fall, Purple Finches are regular migrants through the Lower Susquehanna River Watershed. Northbound movements usually peak in April and early May. During the summer, these birds nest primarily in cool coniferous forests to our north. Then, in October and November each year, they make another local appearance on their way to wintering grounds in the southeastern United States. A significant population of Purple Finches remains to our north through the colder months, inhabiting spruce-pine and mixed forests from the Great Lakes east through New England and southeastern Canada. This population can be irruptive, moving south in conspicuous numbers to escape inclement weather, food shortages, and other environmental conditions. Every few years, these irruptive birds can be found visiting suburbs, parks, and feeding stations—sometimes lingering in areas not often visited by Purple Finches. Right now, Purple Finches in flocks larger than those that moved through earlier in the fall are being seen throughout the lower Susquehanna valley. Snow and blustery weather to our north may be prompting these birds to shift south for a visit. Here are some looks at members of a gathering of more than four dozen Purple Finches we’ve been watching in Lebanon County this month…







As the autumn bird migration draws to a close for 2024, we’re delighted to be finding five of our favorite visitors from the coniferous and mixed forests of Canada and the northernmost continental United States.






While right now is the best time to get out and look for these species from the northern forests, any or all of them could linger into the winter months, particularly where the food supply is sufficient and conifers and other evergreens provide cover from the blustery weather.
For many species of terrestrial vertebrates living in the lower Susquehanna valley, it’s time to take refuge in a safe place below ground to enter a winter-long slumber. The numerous frosty nights of the past two weeks have expedited the stragglers’ efforts to find a suitable place to pass our coldest months.


And now, just in time for Halloween, a look at some hibernating species that some of our more squeamish readers consider to be “scary”.
In the mountainous forests of the Ridge and Valley Province, there lives a seldom seen little mouse which, unlike the more familiar species found in the fields, farms, and homes of our valleys and Piedmont, spends almost half the year in true hibernation.

In spring and fall, Eastern (Black) Ratsnakes are frequently seen basking in the sun as they absorb heat and get their metabolism going. During the hottest days of summer, when ambient air temperature is sufficient for their needs, they become nocturnal, hunting mice and other creatures that are also active at night. During October, they make their way back to a winter den where they will remain until March or April.




That’s right, all three of these snakes are known to cohabitate, not just during hibernation, but at other times of the year as well. And you thought they were mean and nasty to anything and everything in their path, didn’t you?
Here in the northeastern United States, fear of indigenous wild snakes is a totally irrational anxiety. It’s a figment of our indoctrination. Their wicked reputation is almost exclusively the result of a never-ending stream of demonizing propaganda from the pulpit, press, parents, panicked, and picture shows. All they want from you and I is to be left alone. Want something to really be afraid of this Halloween? Try domestic dogs. That’s right—the “friendly” pooch. In the United States, they’ll land hundreds of people in the emergency room today. Don’t like that one. How ’bout cars and trucks. They’ll kill and maim people all day long. And don’t forget about sugar. Yes friends, that sweet treat is pure poison that kills all day long. Happy Halloween!
SOURCES
Merritt, Joseph F. 1987. Guide to the Mammals of Pennsylvania. University of Pittsburgh Press. Pittsburgh, PA. pp.230-233.
Shaffer, Larry L. 1991. Pennsylvania Amphibians and Reptiles. Pennsylvania Fish Commission. Harrisburg, PA.
During the past week, Uncle Tyler Dyer has been out searching for autumn leaves to add to his collection. One of the species he had not encountered in previous outings was the American Elm (Ulmus americana), so he made a special trip to see a rare mammoth specimen in a small neighborhood park (Park Place) along Chestnut Street between 5th and Quince Streets in Lebanon, Pennsylvania.


There’s still time to get out and see autumn foliage. With warmer weather upon us—at least temporarily—it’s a good time to go for a stroll. Who knows, you might find some spectacular leaves like these collected by Uncle Ty earlier this week. All were found adorning native plants!






During your foray to view the colorful foliage of the autumn landscape, a little effort will reveal much more than meets the eye of the casual observer.






















You too can experience the joys of walking and chewing gum at the same time, so grab your field glasses, your camera, and your jacket, then spend lots of time outdoors this fall. You can see all of this and much more.
Don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab at the top of this page to help you find a place to see both fall foliage and migrating birds of prey in coming weeks. And click the “Trees, Shrubs, and Woody Vines” tab to find a photo guide that can help you identify the autumn leaves you encounter during your outings.

Bathed in glowing sunshine, a very large fallout of migrating Neotropical songbirds enlivened the forest edge atop Second Mountain in northern Lebanon County, Pennsylvania, this morning. While last night’s flight was widespread beneath a dome of atmospheric high pressure covering the Mid-Atlantic States, this is a look at some of the 500 -1,000 migrants observed feeding on insects and other natural foods at just this single location.
























Many of the observers at the Second Mountain Hawk Watch commented that this morning’s fallout was by far the best they had seen anywhere in the region during recent years. Others believed it to be the best they had ever seen. It was indeed less like a “wave” of migrants and more like a “tsunami”. Choosing a good viewing location and being there at the right time can improve your chances of seeing a spectacle like this. The good news is, it looks like another big flight is currently underway, so finding a forest edge on a ridgetop or along a utility right-of-way just might pay off for you early tomorrow morning.

Clear, cool nights have provided ideal flight conditions for nocturnal Neotropical migrants and other southbound birds throughout the week. Fix yourself a drink and a little snack, then sit down and enjoy this set of photographs that includes just some of the species we found during sunrise feeding frenzies atop several of the Lower Susquehanna River Watershed’s ridges. Hurry up, because here they come…





































The migration is by no means over; it has only just begun. So plan to visit a local hawkwatch or other suitable ridgetop in coming weeks. Arrive early (between 7 and 8 AM) to catch a glimpse of a nocturnal migrant fallout, then stay through the day to see the hundreds, maybe even thousands, of Broad-winged Hawks and other diurnal raptors that will pass by. It’s an experience you won’t forget.

Be certain to click the “Birds” tab at the top of this page for a photo guide to the species you’re likely to see passing south through the lower Susquehanna valley in coming months. And don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab to find a hawk-counting station near you.

Back on March 24th, we took a detailed look at the process involved in administering prescribed fire as a tool for managing grassland and early successional habitat. Today we’re going turn back the hands of time to give you a glimpse of how the treated site fared during the five months since the controlled burn. Let’s go back to Middle Creek Wildlife Management Area for a photo tour to see how things have come along…















Elsewhere around the refuge at Middle Creek, prescribed fire and other management techniques are providing high-quality grassland habitat for numerous species of nesting birds…



We hope you enjoyed this short photo tour of grassland management practices. Now, we’d like to leave you with one last set of pictures—a set you may find as interesting as we found them. Each is of a different Eastern Cottontail, a species we found to be particularly common on prescribed fire sites when we took these images in late May. The first two are of the individuals we happened to be able to photograph in areas subjected to fire two months earlier in March. The latter two are of cottontails we happened to photograph elsewhere on the refuge in areas not in proximity to ground treated with a prescribed burn or exposed to accidental fire in recent years.


These first two rabbits are living the good life in a warm-season grass wonderland.


Oh Deer! Oh Deer! These last two rabbits have no clock to track the time; they have only ticks. Better not go for a stroll with them Alice—that’s no wonderland! I know, I know, it’s time to go. See ya later.
The Aphrodite Fritillary (Speyeria aphrodite), also known simply as the Aphrodite, is a brush-footed butterfly of deciduous, coniferous, and mixed forests. We found this female in a grassland margin between woodlots where prescribed fire was administered during the autumn of 2022 to reduce accumulations of natural fuels and an overabundance of invasive vegetation. A goal of the burn was to promote the growth of native species including the violets (Viola species) favored as larval host plants by this and other fritillaries.

By the time these adult butterflies make their reproductive flights in late summer, the violets that serve as larval host plants have gone dormant. To find patches of ground where the violets will come to life in spring, the female Aphrodite Fritillary has an ability to sense the presence of dormant roots, probably by smell. Upon finding an area where suitable violets will begin greening up next year, she’ll deposit her eggs. The eggs overwinter, then hatch to feed on the tender new violet leaves of spring.


Here’s a native plant you don’t see very often, but Ruby-throated Hummingbirds have a knack for finding and adoring it within the limited habitat where it still exists.



Not likely to thrive in deep forest cover, Allegheny Vine is a denizen of edge habitat. The species is dependent on some type of disturbance to maintain suitable growing conditions. The plants seen here were found flowering in an area that had experienced a fire prior to last year’s growing season. It is therefore quite possible that the fire completed the stratification process and triggered long-dormant seeds to germinate last spring or summer to develop a basal plant which matured and flowered during this second summer of the biennial’s growth. On a forested slope opposite this site, a first-ever prescribed burn was conducted in March of this year to eliminate accumulated fuel and replicate a natural fire cycle. With a little luck, this forest management approach may prompt additional long-dormant Allegheny Vine seeds to germinate and form basal plants this year for maturation in 2025. Without man-made disturbances, Allegheny Vine may remain viable as a species by enduring seed dormancy periods of 40-100 years or more between fires, lightning strikes, wind storms, ice accumulations, and other events which clear the canopy and encourage growth.

It’s hard to believe, but for almost two months now, sandpipers, plovers, and terns have been filtering south through the Lower Susquehanna River Watershed on their way to the Atlantic coastline as they complete the first leg of their long autumn migration—a journey that will take some species all the way to the far reaches of the South American continent for winter.

As August draws to a close, these early birds are being joined by widespread nocturnal flights of Neotropical migrants—those species, primarily songbirds, on their way to wintering grounds which lie exclusively south of the continental United States.
To catch a glimpse of these night-flying avians, your best bet may be to position yourself on the crest of a ridge or along a linear break in the forest such as a utility right-of-way where waves of warblers, vireos, flycatchers, and other Neotropical passerines sometimes feed on invertebrates after making landfall at daybreak. Pick a place where the trees are bathed in the warm light of the rising sun and be there by 7 A.M. E.D.T. The activity can be tremendous, but it usually ends between 8 and 9.







Diurnal migrants, birds that make their movements during the daylight hours, are ramping up their flights now as well. Broad-winged Hawks, Bald Eagles, and falcons are currently being tallied at hawk-counting stations throughout the northeast. Many of those lookouts are seeing Ruby-throated Hummingbirds, swallows, and other daytime migrants too.





Autumn migration flights are an ever-changing process, with different species peaking at different times throughout the season. In these months just after the nesting season, each of these species is more numerous than at any other time of the year. And of course, the more often we as observers get out and have a look, the more of them we’ll see.
Be certain to click the “Birds” tab at the top of this page for a photo guide to the species you’re likely to see passing through the lower Susquehanna valley this fall. Nearly four months of autumn hawk migration flights lie ahead, so don’t forget to click the “Hawkwatcher’s Helper: Identifying Bald Eagles and other Diurnal Raptors” tab to find a hawk-counting station near you, then stop by for a visit or two. See you there!


Do you recall our “Photo of the Day” from seven months ago…

Well, here’s what that site looks like today…


And there are pollinating insects galore, most notably butterflies…


















Why on earth would anyone waste their time, energy, and money mowing grass when they could have this? Won’t you please consider committing graminicide this fall? That’s right, kill that lawn—at least the majority of it. Then visit the Ernst Seed website, buy some “Native Northeast Wildlflower Mix” and/or other blends, and get your meadow planted in time for the 2025 growing season. Just think of all the new kinds of native plants and animals you’ll be seeing. It could change your life as well as theirs.

Resilient to the pressures of flooding, ice scour, drought, and oft times really poor water quality, Water Willow (Dianthera americana, formerly Justicia americana) is the most common herbaceous plant on the Susquehanna’s non-forested alluvial islands. Yet, few know this native wildflower by name or reputation.



The spring of 2024 has been very kind to our beds of Water Willow. Rainfall in the Susquehanna watershed has been frequent enough to maintain river levels just high enough to keep the roots of the plants wet. During the interludes in storm activity, dry spells have rolled back any threat of flooding on the river’s main stem, thus eliminating chances of submerging the plants in muddy water and preventing the sun from keeping them warm, happy, and flowering early. Thundershowers throughout the basin earlier this week have now raised the river a few inches to inundate the base of the plants and make mats of Water Willow favorable places for newly hatched fry and other young fish to take refuge while they grow. Here’s a look…









By now you’ve come to appreciate the importance of Water Willow to the sustainability of our populations of fish and other aquatic life. Like similar habitat features that reduce sediment runoff and nutrient pollution, undisturbed stands of terrestrial, emergent, and submerged native plant species are essential to the viability of our freshwater food webs.
Yesterday, while photographing damselflies on a rehabilitated segment of a warmwater lower Susquehanna valley stream, we noticed some oddly chunky small fish gathered on the surface of a pool along the shoreline.

Upon further inspection, they appeared to be fingerlings of some type of sunfish or bass. Time for a closer look.





In the Lower Susquehanna River Watershed, the Largemouth Bass is an introduced species, a native transplant from the Mississippi watershed and Atlantic Slope drainages south of the Chesapeake.

During the past week, we’ve been exploring wooded slopes around the lower Susquehanna region in search of recently arrived Neotropical birds—particularly those migrants that are singing on breeding territories and will stay to nest. Coincidentally, we noticed a good diversity of species in areas where tent caterpillar nests were apparent.


Here’s a sample of the variety of Neotropical migrants we found in areas impacted by Eastern Tent Caterpillars. All are arboreal insectivores, birds that feed among the foliage of trees and shrubs searching mostly for insects, their larvae, and their eggs.








In the locations where these photographs were taken, ground-feeding birds, including those species that would normally be common in these habitats, were absent. There were no Gray Catbirds, Carolina Wrens, American Robins or other thrushes seen or heard. One might infer that the arboreal insectivorous birds chose to establish nesting territories where they did largely due to the presence of an abundance of tent caterpillars as a potential food source for their young. That could very well be true—but consider timing.





So why do we find this admirable variety of Neotropical bird species nesting in locations with tent caterpillars? Perhaps it’s a matter of suitable topography, an appropriate variety of native trees and shrubs, and an attractive opening in the forest.





Here in the Lower Susquehanna River Watershed, the presence of Eastern Tent Caterpillar nests can often be an indicator of a woodland opening, natural or man-made, that is being reforested by Black Cherry and other plants which improve the botanical richness of the site. For numerous migratory Neotropical species seeking favorable places to nest and raise young, these regenerative areas and the forests surrounding them can be ideal habitat. For us, they can be great places to see and hear colorful birds.
