Seventeen-year Cicadas: Watching a Nymph Transform

Seventeen-year Periodic Cicadas have been emerging slowly and silently in my east Tennessee yard for the past week.  No drumming music to attract mates.  No sound at all.  (See more about this in my previous post:  Seventeen-year Cicadas Emerging in Tennessee.) But, for the past two days they have been more active, disappearing up into the trees.   And today it is sunny and 69 F degrees.  A moment ago, a cicada flew by me clicking.

This slow period has offered unexpected opportunity for me to see several nymph transformations.  The adult insect emerges from its nymph shell in a soft white stage, before the exoskelton and wings have had time to harden and become the mature insect we normally see.  If I had not seen Sir David Attenbourough's excellent video, Amazing Cicada Life Cycle, I would not have known I was looking at the same insect.  

I encountered this change as it was progressing and photographed it intermittently for 79 minutes.  These transformations are happening constantly as the cicada nymphs crawl out of the ground.  It is the most magical part of the whole metamorphosis and most of the time we don't even notice cicadas until they begin their deafening song.  That is, unless they are all over your garden.

Even when they are all over your garden, as they are mine, there is nothing to feel concern about.  They aren't feeding.  They fed like crazy on tree root sap under the ground for seventeen years.  Now all they care about is mating and starting their seventeen year cycle all over again.

Notice the wings starting to increase.  They expand rapidly as the cicada emerges from the nymph excoskeleton which then becomes an empty casing.

For a period of time they hang from their casing, drying and hardening the wings and exoskeleton.  Then their wings fold over their back, still with a silvery look, until the process of hardening changes the cicada into the black, red-eyed insect we normally see.

As the weather warms both the ground and the air, the quiet will fade and the air will fill with thousands of flying and singing cicadas.  For two weeks they will mate, lay eggs, feed wildlife and fertilize the ground.  Their larvae will hatch, fall to the ground, burrow under trees in search of root sap, and start the life-cycle all over again.  

This is the second in a two-part series on the seventeen-year cicadas in east Tennessee.  To see the first post visit:  Seventeen-year Cicadas Emerging in Tennessee

Seventeen-year Cicadas are Emerging in Tennessee

You will seldom see posts from me about insects.  I value them and appreciate their contribution to our natural world but they are not generally the focus of my art or my writing.  This insect, however, has my attention.  The Seventeen-year Periodic Cicada, also known as Brood-X, Magicicada septendecim.  

An insect that spends seventeen years underground, feeding on the sap of trees, only to emerge seventeen years later, for only two weeks, to sing, breed, lay eggs, and begin this life-cycle all over again. 

I've been through a seventeen-year emergence before, aware of it only because of the noise.  Thousands of males, all at once, flexing a drum-like organ in their abdomen.  It can be deafening.  But right now there is no sound.  There is just this slow, steady increase in numbers.  Speculation is that the temperatures have been too cold and everything will change when the ground warms up to 64F degrees.

This emergence is different for another reason. It is happening in my yard.  The quiet is eerie.  Does it mean only females have emerged? Are the males just two cold to sing?  East Tennessee's May has been unseasonably cold with many days hovering in the 50's F.  These cicadas are lounging near the ground, on ferns, viburnum, coral bells, even the ginger, any plant that happens to be nearby when they exit the ground.  They are also climbing the beech trunks and if you think to look over-head, you'll find them hanging out in the lower canopy.  

According to science, these insects like to emerge when its warm, a ground temperature of 64 F degrees at least.  But mine are emerging anyway.  Quietly, almost secretively.  Slowly.  The sheer numbers are starting to feel creepy.  And while we are waiting for the full effect, I want you to see what I refer to as the "fairy princess" phase of cicada metamorphosis.  

I think this phase is magical, the beautiful, delicate wing pattern and lovely yellow trim.  And yes, that other-worldly face. You can see more of that in my next post as I show you just how the cicada looks emerging from that empty casing we often see left behind.

Rose-breasted Grosbeaks, Red-breasted Nuthatches and a Hairy Woodpecker!

Juvenile Rose-breasted Grosbeak watercolor sketch by Vickie Henderson

For those of us who love birds and love to watch them, we have a ready-made source of enjoyment no matter where we are. Autumn, a season of migration, presents delightful opportunities to see birds that only visit our yards briefly enroute to wintering grounds. This season, the birds that caught my eye were the colorful Rose-breasted Grosbeaks.

Even though Rose-breasted Grosbeaks are feeder friendly, they are also shy, a shyness almost equal to our flighty American Goldfinches. Definitely not the boldness of the Carolina Chickadees, Tufted Titmice or Northern Cardinals that frequent the feeders. I had snapped a couple of grosbeak images through the window, but did not find these very satisfying, especially since the red, brown and black patterns on each immature bird varied so greatly and were so much fun. Natural birdy watercolors. Splashes of color and unique shapes while feathers morph into patterns that more resemble parents. 

Hoping to be as non-threatening as the stone wall behind me, I settled myself on my porch a distance away, camera in hand. Being still has its rewards! My first surprise was the arrival of our resident male Hairy Woodpecker. He alerts all to his presence with his loud chirps, much to my appreciation. I loved that he hung around on a trunk for a few photos while he checked out the rainy day crowd at the feeders.  

Next, Red-breasted Nuthatches! An irruptive species that we only see in Tennessee when conditions bring them farther south for food.  Fiesty little nuthatches with distinctive personalities, they fly in fearlessly and leave just as swiftly except when they want to display a nut meat? 

This nuthatch held his nut piece high in the air and turned his head this way and that way, as though displaying it to other nuthatches? 

Later I heard a "convention" of nuthatches over my head having a big discussion, everybody "talking at once"! "Toutie, tou, tou, tou, toutie-tou." I even searched for an owl as a possible reason for their excited vocalizations. I would have loved to have been able to count them. Just how many nuthatches was I seeing and hearing? Was it just two or a whole flock?  

I did find a shy immature male Rose-breasted Grosbeak, hiding in the leaves near the feeders. Patience rewarded me with a clear view as he finally ventured more into the open after a few minutes. 

Without a doubt, being still draws you deeper into the natural world around you, stirring renewal and wonder. For an instant, you are present, transported, and a part of it. Alive and curious.  Armed with more questions than answers, you leave that moment reluctantly but satisfied and eager to do it again!

Migrating Thrushes are in Town!

In Knoxville, in the east Tennessee Valley, fall brings migrating warblers, thrushes and other species into open wooded areas for food.  That would be a good description of my yard--a wooded edge.  And when you think a rainy day takes away your birding opportunities, think again!    

Gray-cheeked Thrush

I've been hearing thrushy "pit" calls for the past week, but searching for the owners of these voices has been a challenge.  Even when I caught a glimpse of bird movement, it was too brief to ID the bird.  I have enjoyed a brief Swainson's Thrush song and a "vree" like call over the week but still no visual IDs until today!

I definitely feel charmed when I walk by my dining room window and spot a bird fluttering in the dogwood.  This time, I was doubly lucky.  My first bird was the elusive Gray-cheeked Thrush.  Last May this thrush was an accidental find and a life-bird for me in addition to being a new bird ID for the yard.  Once again I found a Gray-cheeked thrush in the same location.  Two of them, and now I feel certain they are regular visitors to the yard during migration. 

A Swainson's Thrush flew in next (above) and displaced the Gray-cheeked Thrush.  The Swainson's showed a nice contrast in the eye and in body color.  In these two individuals, the Swainson's Thrush was more brown in appearance, but more importantly, the eye ring was distinctive.  

Like many of our bird observations, my view of the Swainson's Thrush was brief.  The Swainson's departed and was replaced by another Gray-cheeked Thrush.  This one was darker in appearance and I assumed wetter from the rain.  I believe it was a second Gray-cheeked.  

This one reminded me of why the dogwood is a great place to watch for berry-loving thrushes.  

A great moment of in-door, rainy day birding!

Juvenile Hummingbird Behavior

Young hummingbirds leave the nest full of curiousity and uncertainty. 

They have to figure things out quickly and innocence is short-lived, but their initial hesitation and confusion is easy to spot in the garden.  The hummingbird population in my yard in east Tennessee more than doubled in mid July when the first broods of nestlings left the nest.  A male Ruby-throated hummer dominated the five feeders on the garden side of the house, but he tolerated other hummingbirds in the garden. 

This made juvenile-watching opportunities!  How do you know you are watching a young hummingbird?  Behavior.  Before they become aggressive bombardiers, chasing each other with bad tempers, their behavior is tentative.

Still strengthening their wing muscles, they sometimes perch on stems to find nectar and insects or just to pause and look around.

Which part of this flower has the nectar anyway?

Hummingbird and Coneflowers.  Original watercolor by Vickie Henderson.

Common Grackles Dining on Acorns

If you happen to be outside when a flock of grackles arrives, you may want to take shelter!  It may rain acorns!

When mature acorns are abundant in early autumn, flocks of grackles noisely move from tree to tree feasting on the juicy nut meats. The first time a roaming flock landed in the oaks over my house, it sounded like hail was pelting the roof.  I looked out on the deck to see leaves, twigs and pieces of acorns falling like rain from Southern Red Oaks overhanging the house and deck.

Common Grackles noisily feasting in a Red Oak.

While we usually think of grackles as feeding in fields and on the ground, they also dine in trees.  While most of the grackles were in the limbs, some were also foraging on the ground underneath, picking up fallen nut pieces. It was the nut pieces with their serrated edges that intriqued me.  I wondered how they were cracking them open. 

Some birds swallow acorns whole, like wild turkey and some species of pigeons.  They can rely on their strong gullet muscle to crush them for digestion.  Blue Jays pound the acorns with their beak to break them and eat the soft meat inside.  Grackles, on the other hand, have special mouth parts and a strong beak that equips them for breaking acorns.  Their hard palate has a projection referred to as a "keel" that extends downward.  Bird beaks are hinged but they can also flex and move side ways slightly.  Grackles push the acorn against the keel, scoring the shell until it cracks open and the soft interior is exposed.  The edges of the broken acorn look a bit like they've been primatively sawed.  The grackle eats part of the nut and the rest drops to the ground for flock mates to eat.

The acorns of the Southern Red Oak are bright orange on the inside.

The next time a flock of grackles lands in a tree in your yard, step outside to see what's going on.  It's magical.  Besides the sound of their calls and the energy of activity, they are also acrobats!  Some will be hanging upside down to reach acorns!

Resources:
A. J. Marshall, Biology and Comparative Physiology of Birds, Vol 1:  The Common Grackle (Quiscalus) has a hard keel projecting downward from the horny palate and regularly uses this in opening acorns or cracking corn.

Birds of North America/Common Grackle:  Bill has hard, internal keel projecting downward from horny palate, which is sharper and more abrupt anteriorly.  This keel extends below level of tomia [toothed projections along edge of beak] and is used as sawing adaptation to open acorns, which are often completely scored around shorter diameter and then cracked by adduction.

You may also enjoy these bird behavior posts:
Tail Signals from a Spruce Grouse
Delightful Limpkin

Hummingbirds and Hurricanes

Ruby-throated Hummingbird male.

This morning I helped trap hummingbirds for banding at Seven Islands State Birding Park in east Tennessee where local Ruby-throated Hummingbirds are preparing for migration and others are stopping to feed enroute to their wintering grounds in Central America and Southern Mexico.  At the same time, three hurricanes are churning in the south Atlantic, and as I write, hurricane Irma, originally a category 5 hurricane that has devastated many islands in the Carribean, is barreling down on Florida.

Above, Mark Armstrong demonstrates hummingbird banding at Ijams nature center, with Janie Kading assisting.

Knowing that Ruby-throated hummingbird migration is in full swing, I have wondered how these hurricanes have affected their migration.  I asked my friend and east Tennessee hummingbird expert, Mark Armstrong, to share what he knew about storm affects on migration. He answered with these comments:
"Unfortunately I don’t know much about their [hummingbird] survival in a storm.  I’ve heard of birds making landfall on the fringes of other storms and arriving thin and exhausted.  I’ve also read that migration from an evolutionary standpoint is actually across a broad front and a prolonged period so that some part of the population may be affected by adverse weather the majority will not be and survive.  I also keep thinking about Dr. Buehler’s Golden-winged warblers. They were at their breeding territories, left when tornados were heading their way, some went to the Gulf coast and one went back to Cuba.  Then they returned to breeding territories after the threat passed.  That is amazing and we really don’t know what birds may be perceiving and if they are capable of moving away from a danger like a hurricane.  Any small bird I can’t imagine would survive a direct hit from a storm with extremely high winds."

I, for one, am glad that the local hummingbirds frequenting my yard are hanging around and hope they will wait to leave until the many storm threats pass.

Meanwhile, we had a fun surprise during our banding session this morning at Seven Islands.  You may think that the hummingbird pictured above is a mature male Ruby-throat.  But surprise--this is a juvenile!  Normally, we expect to see juvenile males in their first year with scattered red throat feathers like the one pictured in image three or we might see small clusters of three or four red feathers as their gorget begins forming.

This first year male had an almost fully formed gorget, which Mark described as a rare occurrence in his experience.  Mark has banded over 4000 Ruby-throated hummingbirds since he began banding hummingbirds in 2005.  The juvenile pictured had white tail feather tips and other attributes that are the identifying characteristics of juveniles.

Most of our hummingbirds will leave Tennessee by the end of September with some late individuals departing by the second week of October.  Remember to leave at least one feeder out to feed our wintering hummingbirds that come from the west.  These birds often arrive from October to December.  If you should have a hummingbird at your feeder after November 1st, contact Mark Armstrong at Woodthrush@bellsouth.net or 865-748-2224.

Photo credit for banding images:  Mark Armstrong
Why do we band hummingbirds?
Mark Armstrong and banding at Seven Islands
Wintering Hummingbirds in Tennessee
Seven Islands State Birding Park

Hummingbirds and Jewelweed

Recognize this watercolor?  It's the hummingbird painting you see in my blog banner!  

Maine's Wild Seed project contacted me earlier in the year to inquire about using one of my hummingbird paintings with their article on Jewelweed's beneficial relationship with hummingbirds. Life gets busy and after we made arrangements, I actually forgot about it! What a delight to see this beautiful spread of my "Hummer and Jewelweed" painting in the latest publication of Wild Seed, Returning Native Plants to the Maine Landscape. 

Maine's Wild Seed project educates people about the important relationships between native plants and animals and how these relationships support each other.  Their magazine is beautiful, a feast for the eyes and informative to read.  They also have tons of helpful information and resources available on their website:  http://wildseedproject.net/  Pay them a visit and plant native plants!

Maine's Wildseed Project
Hummer and Jewelweed prints on my website, Vickie Henderson Art