Blooming in Early July: Great Rhododendron

With the gasoline and gunpowder gang’s biggest holiday of the year now upon us, wouldn’t it be nice to get away from the noise and the enduring adolescence for just a little while to see something spectacular that isn’t exploding or on fire?  Well, here’s a suggestion: head for the hills to check out the flowers of our native rhododendron, the Great Rhododendron (Rhododendron maximum), also known as Rosebay.

Great Rhododendron
The Great Rhododendron is an evergreen shrub found growing in the forest understory on slopes with consistently moist (mesic) soils.  The large, thick leaves make it easy to identify.  During really cold weather, they may droop and curl, but they still remain green and attached to the plant.

Thickets composed of our native heathers/heaths (Ericaceae) including Great Rhododendron, Mountain Laurel, and Pinxter Flower (Rhododendron periclymenoides), particularly when growing in association with Eastern Hemlock and/or Eastern White Pine, provide critical winter shelter for forest wildlife.  The flowers of native heathers/heaths attract bees and other pollinating insects and those of the deciduous Pinxter Flower, which blooms in May, are a favorite of butterflies and Ruby-throated Hummingbirds.

Pinxter Flower in bloom
A close relative of the Great Rhododendron is the Pinxter Flower, also known as the Pink Azalea.

Forests with understories that include Great Rhododendrons do not respond well to logging.  Although many Great Rhododendrons regenerate after cutting, the loss of consistent moisture levels in the soil due to the absence of a forest canopy during the sunny summertime can, over time, decimate an entire population of plants.  In addition, few rhododendrons are produced by seed, even under optimal conditions.  Great Rhododendron seeds and seedlings are very sensitive to the physical composition of forest substrate and its moisture content during both germination and growth.  A lack of humus, the damp organic matter in soil, nullifies the chances of successful recolonization of a rhododendron understory by seed.  In locations where moisture levels are adequate for their survival and regeneration after logging, impenetrable Great Rhododendron thickets will sometimes come to dominate a site.  These monocultures can, at least in the short term, cause problems for foresters by interrupting the cycle of succession and excluding the reestablishment of native trees.  In the case of forests harboring stands of Great Rhododendron, it can take a long time for a balanced ecological state to return following a disturbance as significant as logging.

Birds of Conewago Falls in the Lower Susquehanna River Watershed: Ruffed Grouse
Ruffed Grouse (Bonasa umbellus) may be particularly sensitive to the loss of winter shelter and travel lanes provided by thickets of Great Rhododendron and other members of the heather/heath family.  (Vintage 35 mm image)

In the lower Susquehanna region, the Great Rhododendron blooms from late June through the middle of July, much later than the ornamental rhododendrons and azaleas found in our gardens.   Set against a backdrop of deep green foliage, the enormous clusters of white flowers are hard to miss.

Great Rhododendron Flower Cluster
Great Rhododendrons sport an attractive blossom cluster.  The colors of the flower, especially the markings found only on the uppermost petal, guide pollinators to the stamens (male organs) and pistil (female organ).
Bumble Bee Pollinating a Great Rhododendron Flower
To this Bumble Bee (Bombus species), the yellowish spots on the uppermost petal of the Great Rhododendron may appear to be clumps of pollen and are thus an irresistible lure.  

In the Lower Susquehanna River Watershed, there are but a few remaining stands of Great Rhododendron.  One of the most extensive populations is in the Ridge and Valley Province on the north side of Second Mountain along Swatara Creek near Ravine (just off Interstate 81) in Schuylkill County, Pennsylvania.  Smaller groves are found in the Piedmont Province in the resort town of Mount Gretna in Lebanon County and in stream ravines along the lower river gorge at the Lancaster Conservancy’s Ferncliff and Wissler’s Run Preserves.  Go have a look.  You’ll be glad you did.

Great Rhododendron along Route 125 near Ravine
Great Rhododendron along Route 125 along the base of the north slope of Second Mountain north of Ravine, Schuylkill County, Pennsylvania.
Great Rhododendron along Swatara Creek
Great Rhododendrons beginning to bloom during the second week of July along Swatara Creek north of Ravine, Schuylkill County, Pennsylvania.  Note how acid mine drainage continues to stain the rocks (and pollute the water) in the upper reaches of this tributary of the lower Susquehanna.

Identification of the Three Species of Brood X Periodical Cicadas

The emergence of Brood X Periodical Cicadas is now in full swing.  If you visit a forested area, you may hear the distant drone of very large concentrations of one or more of the three species that make up the Brood X event.   The increasing volume of a chorus tends to attract exponentially greater numbers of male cicadas from within an expanding radius, causing a swarm to grow larger and louder—attracting more and more females to the breeding site.

Holes in the ground where emerging Brood X Periodical Cicadas have come to the surface.
The exuvia of Periodical Cicadas that, following emergence from the soil, have ascended the trunk of an Eastern White Pine.  The exuvia is the exoskeletal remains of the cicada’s final molt from a nymph into a flying adult.

Each Periodical Cicada species has a distinctive song.  This song concentrates males of the same species at breeding sites—then draws in an abundance of females of the same species to complete the mating process.  Large gatherings of Periodical Cicadas can include all three species, but a close look at swarms on State Game Lands 145 in Lebanon County and State Game Lands 46 (Middle Creek Wildlife Management Area) in Lancaster County during recent days found marked separation by two of the three.  Most swarms were dominated by Magicicada septendecim, the largest, most widespread, and most common species.  However, nearly mono-specific swarms of M. cassinii, the second most numerous species, were found as well.  An exceptionally large one was northwest of the village of Colebrook on State Game Lands 145.  It was isolated by a tenth of a mile or more from numerous large gatherings of M. septendecim cicadas in the vicinity.  These M. cassinii cicadas, with a chorus so loud that it outdistanced the songs made by the nearby swarms of M. septendecim, seized the opportunity to separate both audibly and physically from the more dominant species, thus providing better likelihood of maximizing their breeding success.

Some of the tens of thousands of M. cassinii Periodical Cicadas in a concentration on State Game Lands 145 northwest of Colebrook in Lebanon County, Pennsylvania.  This swarm occupied deciduous and evergreen trees on several acres of a south-facing hillside.  To provide protection from predators and assure the chance of finding a mate “in the crowd”, lesser numbers of this and the rarer species, Magicicada septendecula, would need to merge into the swarms of the abundant M. septendecim Periodical Cicadas to breed.

The process of identifying Periodical Cicadas is best begun by listening to their choruses, songs, and calls.  After all, the sounds of cicadas will lead one to the locations where they are most abundant.  The two most common species, M. septendecim and M. cassinii, produce a buzzy chorus that, when comprised of hundreds or thousands of cicadas “singing” in unison, creates, when heard from a distance, a droning wail that can carry for a quarter of a mile or more.  It’s a surreal humming sound that may remind one of a space ship from a science fiction film.

Listen to the songs of individual cicadas at close range and you’ll hear a difference between the widespread M. septendecim “Pharaoh Periodical Cicada” and the other two species.  M. septendecim‘s song is often characterized as a drawn out version of the word “Pharaoh”, hence the species’ unofficial common name.  As part of their courtship ritual, “Pharaoh Periodical Cicadas” sometimes make a purring or cooing sound, which is often extended to sound like kee-ow, then sometimes revved up further to pha-raohM. cassinii, often known as “Cassin’s Periodical Cicada”, and the least common species, M. septendecula, often make scratchy clicking or rattling calls as a lead-in to their song.  Most observers will find little difficulty locating the widespread M. septendecim “Pharaoh Periodical Cicada” by sound, so listening for something different—the clicking call—is an easy way to zero in on the two less common species.

To penetrate the droning choruses of large numbers of “Pharaoh” and/or “Cassin’s Periodical Cicadas”, sparingly distributed M. septendecula cicadas have a noise-penetrating song consisting of a series of quick raspy notes with a staccato rhythm reminiscent of a pulsating lawn sprinkler.   It can often be differentiated by a listener even in the presence of a roaring chorus of one or both of the commoner species.  However, a word of caution is due.  To call in others of their kind, “Cassin’s Periodical Cicadas” can produce a courtship song similar to that of M. septendecula so that they too can penetrate the choruses of the enormous numbers of “Pharaoh Periodical Cicadas” that concentrate in many areas.  To play it safe, it’s best to have a good look at the cicadas you’re trying to identify.

M. cassinii Periodical Cicadas “singing” from a treetop at Colebrook, Lebanon County, Pennsylvania.  Clicking phrases are sure sign of the presence of this species and/or M. septendecula, the least likely of the three species to be encountered.  When in close proximity to a swarm, a listener will often notice the rising and falling volume of a chorus in a cycle that repeats every few seconds, an effect caused by cicadas attempting to synchronize their songs in a harmony with others in the group.  When courtship and mating is complete, female Periodical Cicadas will begin laying eggs in slits made in fresh new growth at the ends of branches on deciduous trees like the one seen here.

Visually identifying Brood X Periodical Cicadas to the species level is best done by looking for two key field marks—first, the presence or absence of orange between the eye and the root of the wings, and second, the presence or absence of orange bands on the underside of the abdomen.  Seeing these field marks clearly requires in-hand examination of the cicada in question.

Observing a perched Brood X Periodical Cicada can sometimes provide a view of the key field marks needed for identification of the species.  On the M. septendecim “Pharaoh Periodical Cicada” seen here, the orange patch between the eye and wing root and the orange bands on the underside of the abdomen are visible.
The abdomen of this perched M. cassinii “Cassin’s Periodical Cicada” appears, when viewed through the wings, to have orange bands.  But, examination in hand would show an all-black abdomen with glossy surfaces shining in the sunlight.  For accuracy, the up-close-and-personal look is necessary.
In the hand, cicadas can be better studied for key field marks.  M. septendecim (top) is larger than M. cassini (bottom) and M. septendecula, but the difference is not always apparent, particularly when a direct comparison cannot be made.

To reliably separate Brood X Periodical Cicadas by species, it is necessary to get a closeup view of the section of the thorax between the eye and the root (insertion) of the wings, plus a look at the underside of the abdomen.  Here’s what you’ll see…

Magicicada septendecim—“Pharaoh Periodical Cicada”

M. septendecim has an orange patch between the eye and the root of the wings.
The underside of M. septendecim’s abdomen has orange bands or stripes along the trailing edge of each segment. The width of the bands can vary, but is typically wider on males (left) than on females (right).

Magicicada cassinii—“Cassin’s Periodical Cicada”

The thorax of M. cassinii is black between the eye and the wing insertion.
The underside of M. cassinii’s abdomen is all black without orange bands or stripes in both the male (left) and female (right).

Magicicada septendecula

M. septendecula’s thorax is black between the eye and root of the wings.
The underside of M. septendecula’s abdomen has narrow orange bands or stripes along the trailing edge of each segment.  The width of the bands can differ.  Those of this male (left) are minimal and the bands on this female (right) are near the maximum for the species.

There you have it.  Get out and take a closer look at the Brood X Periodical Cicadas near you.

The abundant and widespread “Pharaoh Periodical Cicada” (M. septendecim).
It’ll all be over before long.  Accumulating remains of M. cassinii “Cassin’s Periodical Cicadas” beneath an Eastern White Pine at the site of the Colebrook State Game Lands swarm.

More than a Mint Dish

On a snowy winter day, it sure is nice to see some new visitors at a backyard feeding station.  Here at the susquehannawildlife.net headquarters, American Robins have arrived to partake of the offerings.

American Robins feed on peanut hearts and chopped apples.

For this flock of robins, which numbered in excess of 150 individuals, the contents of this tray were a mere garnish to the meal that would sustain them through 72 hours of stormy weather.  The main course was the supply of ripe berries on shrubs and trees in the headquarters garden.

Their first choice—the bright red fruits of the Common Winterberry.

American Robins strip the fruits from a Common Winterberry.
Eat fast or lose your turn.
Irresistible crimson delights.
Cedar Waxwings get their share too.
Robins will linger until nightfall to feed on winterberries.

After cleaning off the winterberry shrubs, other fruits became part of the three-day-long feast.

Robins eating Highbush Cranberry (Viburnum species) fruits.
The blue-gray berries of junipers are attractive to robins, waxwings, and bluebirds.
The American Holly (Ilex opaca) is a favorite of berry-loving birds.  Its evergreen foliage provides cover and roosting sites for wintering birds.

Wouldn’t it be great to see these colorful birds in your garden each winter?  You can, you know.  Won’t you consider adding plantings of native trees and shrubs to your property this spring?  Here at the susquehannawildlife.com headquarters we mow no lawn; the lawn is gone.  Mixing evergreens and fruit-producing shrubs with native warm-season grasses and flowering plants has created a wildlife oasis absent of that dirty habit of mowing and blowing.

You can find many of the plants seen here at your local garden center.  Take a chunk out of your lawn by paying them a visit this spring.

Want a great deal?  Many of the County Conservation District offices in the lower Susquehanna region are having their annual spring tree sales right now.  Over the years, we obtained many of our evergreens and berry-producing shrubs from these sales for less than two dollars each.  At that price you can blanket that stream bank or wet spot in the yard with winterberries and mow it no more!  The deadlines for orders are quickly approaching, so act today—literally, act today.  Visit your County Conservation District’s website for details including selections, prices, order deadlines, and pickup dates and locations.

Evergreens like this Eastern Hemlock (Tsuga canadensis) are essential to the survival of many species of wintering birds.  Plant evergreens in clumps, the bigger the better, to provide birds with thermal protection against the cold winds of winter nights.
County Conservation District Tree Sales offer bare root evergreens like this Eastern White Pine (Pinus strobus) in packs of five or ten.  Buy a bunch.  Spend this year’s lawn treatment money on them.  Then, get them planted immediately after pickup in the spring and in a few years you’ll have a nice grove of evergreens for wildlife habitat, a wind break, or a privacy screen.
Groves of mixed evergreens among deciduous woods, grasslands, farmlands, or suburbs are ideal cover for wintering wildlife.  These stands attract many species of migrating and nesting birds as well.  Seen here, left to right, are Eastern White Pine, Norway Spruce (Picea abies), and Eastern Red Cedar.  Though not a native species, the Norway Spruce is frequently used for conservation and ornamental plantings in the northeastern United States due to its appealing attributes and lack of invasive characteristics.
Feeding wildlife is great fun.  But remember, if you’re running a hotel for animals, you’ve got to offer more than an after-dinner mint to your tired and hungry guests.  Let’s get planting!

County Conservation District Tree Sales

Consult each County Conservation District’s Tree Sale web page for ordering info, pickup locations, and changes to these dates and times.

Cumberland County Conservation District Tree Seedling Sale—deadline for prepaid orders Tuesday, March 30, 2021.  Pickup 1 P.M. to 5 P.M., Thursday, April 22, 2021, and 8 A.M. to 2 P.M., Friday, April 23, 2021.  https://www.ccpa.net/4636/Tree-Seedling-Sale

Lancaster County Conservation District Tree Sale—deadline for prepaid orders (hand-delivered to drop box) 5 P.M., Friday, March 5, 2021.  Pickup 8 A.M. to 5 P.M., Thursday, April 15, 2021.  https://www.lancasterconservation.org/tree-sale/

Lebanon County Conservation District Tree Sale—deadline for prepaid orders  Thursday, March 11, 2021.  Pickup 9 A.M. to 6 P.M., Friday, May 7, 2021.  https://www.lccd.org/2021-tree-sale/

Perry County Conservation District Tree Sale—deadline for prepaid orders Wednesday, March 24, 2021.  Pickup 10 A.M. to 6 P.M., Thursday, April 8, 2021.  www.perrycd.org/Documents/2021 Tree Sale Flyer LEGAL SIZE.pdf

York County Conservation District Seedling Sale—deadline for prepaid orders Monday, March 15, 2021.  Pickup 10 A.M. to 6 P.M., Thursday, April 15, 2021.  https://www.yorkccd.org/events/2021-seedling-sale