Tuesday, September 26, 2017

The Viburnum Leaf Beetle's Gathering Harm


This fall, before the leaves fall off, check any Viburnum shrubs you know and love, whether in your yard or in your favorite nature preserve. Do the leaves look like this, pitted with holes, or even stripped down to the veins?

Most people have heard by now about the Emerald Ash Borer's rapidly multiplying demolition of our ash trees. Lest that devastation not be enough ecological and horticultural tragedy to absorb, there is another invasion underway in Princeton, by the Viburnum leaf beetle. This one--a European insect that first showed up in Canada before spreading to the U.S., is going after our understory, one Viburnum species at a time.




This and the above photo are of Viburnum dentatum, the arrowwood Viburnum, which grows here and there in our woodlands, preferring wetter soils. The light damage could have been done by a native insect, or by the first few Viburnum leaf beetles to show up, suggesting much greater damage the next year. Listed as "highly susceptible" on Cornell's website, the arrowwood Viburnum will be the first to succumb.

The maple leafed viburnum, frequently encountered along the Princeton ridge, is less susceptible and thus isn't showing any damage this year. As the Viburnum leaf beetle increases in numbers and exhausts the most susceptible species through complete defoliation, it will presumably begin attacking those that are less susceptible.

We are not completely helpless as yet another careless introduction to the continent wreaks slow motion havoc. This site offers some ways to prevent the beetles and their larvae from consuming your favorite specimens. As with all environmental damage done, the ecological and aesthetic services these shrubs were providing for free will now start coming with a price tag for human maintenance.

The Cornell site offers another ray of hope. An extension official in Rochester, NY asserts that even highly susceptible species may in the long term become viable again, as predatory insects and soil nematodes build up to prey on the Viburnum leaf beetles. Then, perhaps, the introduced species would come into some sort of ecological balance, doing some damage but not enough to kill the Viburnums.

It's a perfectly logical and reassuring scenario, and yet observation often brings into question the speed and effectiveness of nature's capacity to restore balance and sustain diversity. More often, invasive species remain dominant and destructive, be they Phragmitis, or Japanese stiltgrass, or porcelainberry. I called up the Frick Park Environmental Center in Pittsburgh, where I had first witnessed the devastating impact of Viburnum leaf beetle a decade ago. Asked whether they had seen any signs of balance being restored, they answered, "Not yet."

Related links:

The Pennsylvania extension service also has some useful information.

Past NatureNotes posts about the Viburnum leaf beetle, dating back to 2013, can be found here.

This post explores the likely aftermath of the Emerald Ash Borer invasion currently underway.


Sunday, September 24, 2017

Ragweed and Fall Allergies


One native plant that people suffer from allergies in late summer may be less than thrilled about is ragweed (Ambrosia artemisiifolia). Its flowers are green--there being no need to attract pollinators since it spreads its pollen by air. This solitary plant was found on Hamilton Ave, but a much larger source of all that pollen is nearby.

Gardeners sometimes get the urge to plant gardens on school grounds, but followup tends to get iffy during summer vacation. Thus, many of the 13 or so raised beds at the Princeton High School fill with weeds during the summer, and ragweed is one of the more stellar performers, acing the grab-the-sunlight test.


My younger daughter and I planted one of the beds with native wildflowers--cutleaf coneflower, New England aster, late-flowering thoroughwort--as a sort of mid-summer charging station for pollinators. These species are no shrinking violets, but even so, a late summer weeding yielded a considerable pile of ragweed, etal.


If you're lucky enough not to suffer from fall allergies, it's possible to admire the sheer exuberance of the weeds in these beds: pigweed, horseweed, foxtail, and, alas, ragweed.

Might the fall allergy sufferers in the PHS neighborhood proactively organize to weed the raised beds before the ragweed's flowers mature? Something for someone to put on their digital calendar for next year.

Friday, September 22, 2017

With Trees, Looks Can Be Deceiving


Here's a tree that looks dead, but is probably okay. It's a horse chestnut--a species long associated with historic houses, and like many horse chestnuts lost its leaves early, perhaps due to a leaf blotch fungus. Though planted in front of a newer home, its history is connected to the 18th century house around the corner, once lived in by Joseph Stockton and, reportedly, an occasional sleeping pad for Thomas Jefferson.

And here's a recently planted ash tree a few blocks away at the Westminster parking lot, looking good but not long for the world, due to Princeton's ongoing Emerald Ash Borer invasion. When I saw that ash trees were planted as part of the parking lot expansion, I urged Westminster to get the designers to pay for replacements that would actually live long enough to shade the cars parked beneath them. Hoping I'm wrong about it all, but any followup photo a few years from now will likely show a gap where this tree now stands.

Monday, September 18, 2017

September Captured in Bouquets

Bouquets from the backyard can be a good way to learn the names of plants. The two visible here are cupplant on the left, ironweed on the right.



This one shows off purple coneflower, boneset, Indian grass, a species of sunflower, turtlehead, and clusters of stonecrop--a nonnative sedum that turns color as fall progresses, from green to pink, to burgundy to rich brown.

Friday, September 01, 2017

Stalking Monarchs, and Encountering the Other Milkweed Caterpillar

Note: This post serves as a contrast to the horrific flooding in Houston from Hurricane Harvey, showing how stormwater can drive diversity rather than destruction, if we work with nature rather than against it. Unlike cities, the plants that grow in floodplains are built to pop back up within days or hours after a flood and just keep on growing and flowering. Most of these photos were taken in a detention basin, which is an acre-sized depression in the ground, dug to receive storm runoff from the Smoyer Park parking lot. The purpose is to "detain" the rain that hits the asphalt and that would otherwise rush into the nearby stream. Detaining the water reduces flooding in downstream neighborhoods. The detained water then either seeps into the ground or is slowly released through a small pipe into the stream after the floods have receded. 

Last year, a collaboration of federal and local governments with the Friends of Herrontown Woods converted this mowed basin into a wet meadow with floodplain plant species that thrive with these periodic pulses of runoff. Without regulations requiring it, the concave setting for this lovely oasis for native plants and pollinators would not exist, and the polluted runoff from the parking lot would have flowed straight into the local stream, contributing to flash floods.


Nature has offered up some surprises, here in the doldrums of summer, when people who aren't somewhere else sometimes feel like they should be. There was the unexpected, and unexpectedly affecting, chance to capture family portraits of black vultures in the previous posts; the weather has been unexpectedly cool; rains have come when needed for the third year in a row, and monarchs have proved resilient, rebounding from their diminishing numbers in recent years. Not many, as yet, but more.

Thinking them elusive creatures, I figured a zoom lens was necessary to capture their image. First came a peekaboo shot on the far side of a thistle at the Smoyer Park detention basin that we converted last year to (mostly) native meadow.




The blooms of Indian grass got pleasantly in the way of this shot.

With nowhere else to go in a sea of soccer and baseball fields, the monarch kept circling around the planted meadow, encouraging patient waiting for a chance at an unobstructed view. Finally, a clear shot from 100 feet away, while it perched briefly on a river birch. Congratulating myself on some success with a powerful camera, I plunged into the meadow to weed out a small clump of foxtail grass that would become way too numerous if allowed to go to seed.

And there, five feet away from my tugging and clipping, landed the monarch, easily photographed with an iPhone,



with a coppery background of Indian grass. That's what weeding a wild garden does--it immerses the gardener, creating opportunities for serendipity to work its magic.

Just across Snowden Lane from the park, behind Veblen House where our Friends of Herrontown Woods group has fashioned a clearing by removing invasive shrubs and wisteria, another sort of caterpillar munched on the leaves of common milkweed, which has prospered in the resulting sunlight.

Displaying proper Princeton colors, the milkweed tiger moth needed every milkweed plant there, and then some. We came back a week later and found every milkweed stripped down to bare stems. The common milkweed's strategy of aggressive underground spreading becomes more understandable, given the voracious appetites of these caterpillars.


Also called the milkweed tussock moth, the caterpillars become more colorful as they grow. As an adult moth, they are said to retain the cardiac glycosides they pick up from eating milkweed, and warn bats of their unpalatability by emitting a click as they fly about at night.

With summer almost over, a first sighting of a monarch larvae--on a purple milkweed, of which there are very few in Princeton, for some reason. Common milkweed can be a bit too aggressive in a garden, and swamp milkweed disappeared from our garden after a few years. Purple milkweed with its showy blooms may be a good alternative, if we can find any seed after the hungry caterpillar is done.

Wednesday, August 30, 2017

The Saga of the Black Vulture Family Continues


Now we know what the Muppets creators used as a model for Big Bird. This is one of two black vulture fledglings born this summer at the Veblen farmstead in Herrontown Woods. In this photo, it's perched on the first story roof of the Veblen Cottage, which almost got demolished this summer, but it looks like we'll now have a chance to save it. There are many ways in which culture intersects with and complements nature at Herrontown Woods, and this is one of them. "Big Bird's" parents--black vultures mate for life and are unusually attentive parents--have been seen around the farmstead for years. Our attention being on other things, this is the first year we've actually witnessed their young.


The farmstead's version of Big Bird is the weaker of the two fledglings, which two days ago were together perching on the cottage, with the healthier one on top of the chimney. That Big Bird somehow found the flying capacity to make it up on the first floor roof is a new accomplishment.

The reason for the parents' absence was made more clear the next morning, when I received an email from birder Laurie Larson. She had just passed by a roadkilled deer near the intersection of 27 and River Road, on the lawn of the Princeton Church of Christ. Some people are ambulance chasers. Taking an interest in vultures means becoming a roadkill chaser, at least for a day.


There were seven black vultures and 3 turkey vultures performing their custodial function on the carcass.


Just getting out of a car 100 feet away was enough to send most of them flying up to ornament the church's cross.

A few continued eating, though. This photo contrasts the heads of a turkey vulture and a black vulture. Turkey vultures are better at soaring, and have a keen sense of smell that allows them to detect dead animals beneath dense tree cover. The black vultures are more dapper, with keen eyes but lousy sense of smell. They often depend on the turkey vultures for finding the food, then shoulder their way in to share in the feast.

Though no juveniles were partaking of roadkill (do they need to lose their facial fuzz first, for sanitation purposes?), the stronger juvenile was missing from nearby Herrontown Woods. In its place was one of the parents, which might have brought some food back for the still stranded juvenile to enjoy, via regurgitation.


Interestingly, the vultures are much less skittish at the cottage, watching us calmly as we watch them from down on the ground. With a good zoom lens, it's possible to inspect the odd growths on their beaks, which seem like they could be a way of telling them apart.

We'll see if Big Bird gains the wherewithal to fly. Clearly the parents haven't given up.

There's lots of interesting info about vultures on the web. New World vultures are not closely related to Old World vultures, but have evolved to similar forms to perform similar ecological functions. One website, with "16 Things You Might Not Know About Vultures," at Annamiticus.com, works to save rhinos and other endangered species. I've emailed them to see if they know Esmond Bradley Martin, who we discovered is a descendant of Andrew Carnegie's childhood friend and business partner Henry Phipps, Jr, and a grandstepson of the builders of Veblen House who has devoted his life to saving rhinos and elephants from extinction.

The adventure of discovering and learning about all the characters associated one way or another with Veblen House and Herrontown Woods continues.

Sunday, August 27, 2017

Black Vultures Close Up--A Photoshoot and Princeton History


Black vultures four--who could ask for anything more? Okay, there are just three in this family photo. We'll get to the fourth one in a minute. This past Sunday, prior to a work session clearing invasive shrubs in Herrontown Woods, and equipped with better cameras, we returned to Veblen Cottage to check in on the black vulture family mentioned in a previous post.

I guess family values aren't the first thing that comes to mind when people think of vultures, but these black vultures are a tight-knit group. That's mom and pop on the right, with the wrinkly skin on their heads (best not to sully any feathers when dipping one's head daintily into rotting carcasses). Hard to know which parent is which. Vultures don't flaunt their sexual identity. And that's a fledgling on the left, still with baby fuzz on the head.

Family means something for black vultures. On this AllAboutBirds site, they are described by the writer as "one of my favorite birds." He describes their characteristic flight pattern: a few beats of the wings followed by a glide." "Highly social birds with fierce family loyalty," he says, "Black Vultures share food with relatives, feeding young for months after they’ve fledged." It may not be coincidence that, in this serendipitous photoshoot, the parents gave their fledgling the top perch on the chimney.


As we snapped photos from below, the birds were surprisingly cooperative, adopting various poses, from noble, to domestic, to nobly domestic.

Laurie Larson, longtime birder in Princeton who has tracked population numbers over the years as part of the Christmas Bird Count (her data and stories below), suggested the fledgling bears a striking resemblance to Voltaire. People have long suspected a ghost residing in the rather disheveled Veblen Cottage. Was it Veblen himself? Einstein? Now we know.

While the three vultures were preening for the camera up on the chimney of the cottage, another fledgling, looking a bit down and out, was hiding in the corn crib. It didn't seem to be able to fly up to join its kin on the chimney.

When I approached, it shuffled out of the corn crib and hid in the brush.

Laurie's Voltaire comparison is spot on, but I also see something of Art Garfunkle here.

As an aside, given that the photos were taken at the Veblen Cottage at Herrontown Woods, Oswald Veblen died on the brink of the 60s era, but Garfunkel, who performed last year in Princeton, shares Veblen's broad interest in math, architecture and great books. Garfunkel initially majored in architecture, and completed coursework for a PhD in math education while part of Simon and Garfunkel. His interest for numbers expressed itself early on as a fascination with the rise of hits on the pop charts. He has kept a full and public accounting of books he has read, including Voltaire in 1969. He also has that second banana status, which Veblen knew well from living, perhaps contentedly enough, in the shadow of his more famous uncle Thorstein and science icons like Einstein and von Neumann. Part of the joy of the Herrontown Woods project is rediscovering the value of forgotten buildings and legacies that have long flown beneath most people's radar.


Here's the farmstead's little barn and corncrib, whose impending demolition earlier this year by the county, along with all the other Veblen buildings, seemed unstoppable until so many people in the community spoke out to support an initiative by Friends of Herrontown Woods (FOHW.org) to save them. Fortunately, for the black vultures as well as the history of Herrontown Woods, Princeton town council swooped in, raptor-like, and snatched victory from the jaws of defeat. FOHW is now working on an agreement with the town to repair and sustain the buildings, while, of course, continuing habitat and trail work, and snapping photos of the local wildlife.


It's funny about the black vultures. They've provided a somewhat haunting presence around the farmstead for years. Not sure what to do with the connotations they carry, we tried to pay them little mind, preferring to talk about the flashy pileated woodpeckers and the elusive great-horned owl. But maybe it's time to give the vultures their due. They are a cleansing force in the universe. They deal with stuff no one else wants to deal with. They find sustenance in unlikely places, and extend the food chain one link further. They're faithful and diligent parents.

I liked this pose, two generations on a branch.

In the distance, you can see the other parent perched on the chimney of the cottage. This was just before they assembled for the group shots on the chimney.

The vultures appreciate the Veblen Cottage's classic design with a chimney at either end. If they knew, they'd appreciate its "balloon" construction, too, meaning the studs extend from the foundation all the way up to the roof. Balloon construction, according to one builder I spoke to, explains why the cottage is still standing, after so much neglect.

Any good photo shoot includes grooming behavior. The parents groomed the juvenile; the juvenile groomed the parents.

One adult aimed for the noble raptor look, confirming the AllAboutBirds writer's view that these vultures are "almost dapper."


Things got downright statuesque here, with the juvenile taking the parents under its wings.

Five days later, we were standing in the Veblen House driveway in late morning when we heard a great ruckus in the treetops behind the barn, not far from the cottage. My friend was giving me advice about fixing up the Veblen House. He didn't have much time, and what he was saying was important. I dismissed the ruckus in the treetops as small birds hassling a crow or hawk or owl. I continued to listen to my friend as the calls reached a blood curdling frenzy. Life was on the line, be it a bird or squirrel. We headed over to take a look just as a large black bird flew off down the hill, the noise fading behind. It looked large enough to have been an eagle.


We walked over to the cottage, and found the second juvenile had been hiding in the crawlspace. It came out and walked ahead of us around the corner,

then hopped onto the old kitchen sink and spread its wings, looking our way, as if to impress us, then hopped down and headed towards the corncrib.

Later, I grew concerned about what might have transpired in the treetops. Who was the aggressor and who was the victim? Eagles are one of the few predators of black vultures, which in turn occasionally prey on weak or injured animals. Was that large dark bird that flew off a vulture, and had it been on the attack or defending its own fledgling? Black vultures lack vocal organs, so the mortal cries must have been generated by something else.

It occurred that the reason the vultures had been so patient with our photoshoot five days prior was that they were lingering at the cottage to guard the weaker fledgling, hoping it would find the strength to join them in flight.

I returned to the Veblen Cottage the next day to find the vultures gone. After years of trying to ignore them, I suddenly felt their absence.
________________________________

Thanks to Laurie Larson for the additional info below on black vultures in Princeton. The black vulture, according to another member of the Friends of Rogers Refuge who keeps careful records, Tom Southerland, was first seen in Princeton on March 2, 1980, as part of a general expansion of range northward into the northeast. He noted that they "sleep in later" than the turkey vultures. Vultures in general have a good excuse for sleeping in, given that the thermals don't get going until the sun's a good ways up.

One of the great draws of Princeton for vultures in general back then was the Winant Farm, later preserved with a conservation easement in 2002 as Coventry Farm, between Mountain Lakes and the Great Road. Mrs. Winant in particular loved vultures, and provided a place where police could leave roadkilled deer for the vultures to eat. Roadkill back then was a steadily increasing problem, as the deer population continued to climb until professional culling was finally begun in 2000 under Mayor Marshand. The dramatic circling of dozens (hundreds?) of vultures over the Winant Farm drew a lot of attention to the birds back when black vultures were first arriving on a scene long dominated by turkey vultures, and led to some careful documentation of their numbers, which Laurie provides, below.
Here is everything I know about Princeton Vultures. I was fascinated with them back in the day. The Coventry Farm roost built up during the 1980s. Originally it was all Turkey Vultures; Black Vultures first appeared in 1984 and their numbers rose steadily, although on our Christmas Bird Counts the Turkey Vultures were always in the majority. The all-time high count of Turkey Vultures for the Princeton count circle still stands at 615, in 1986, which was one of the years Jim Williams and I counted the Coventry Farm vultures. That year, Black Vultures were at 79; the first appearance of the species in the Princeton count was just 2 years earlier at 38, and they peaked in 1994 at 102, with 257 Turkey Vultures, still in the same area/same counters.  The present high count for Black Vultures is now 116, from 2008; I was the compiler at that time. I believe that was a composite of several roosts, including two in Kingston/Griggstown and others around the circle. The roost at Coventry farm didn't exist any more by that time. I moved to Montgomery in 2001 and others began covering the northwest-Princeton territory. It has gone uncounted in recent years except for someone who does Mountain Lakes.
Vultures aren't necessarily easy to count. We worked hard to get exact numbers during that period when the Black Vultures exploded into NJ. Coventry Farm was an excellent indicator site and we tried to census it the same way each year. You are correct that there was a field on the northeast corner of the farm away from the road where the police put road killed deer; this was the time when the deer population exploded and there was not yet any control plan. That was probably the trigger for the creation of the vulture roosts in that area. There were at least three interrelated roost groves -- Coventry Farm itself, North Road/Pretty Brook Road, and the corner of the Great Road and Mountain Avenue. These are all in sight of each other (we used to stand by the road in the new development at Mountain Ave./Great Road to count). All are planted groves of large spruces or hemlocks. The birds shifted around among the three, making it hard to count them. We would try to get an estimate at the end of the day (3-4:30 PM or so) of the vultures going into roost. Also, for comparison, we arranged to visit Mrs. Winant on Count day at 8 AM each year, to count the birds in the pines around her barns before they started to rise and soar for the day. I used to make an appointment every December by sending a note to tell her when we'd be coming.  She would lock up her dogs and come out to greet us and then dish out can after can of dogfood right on the driveway for the vultures. The Black Vultures were much more aggressive and would come right up to the food, pushing the Turkey Vultures aside. I don't know whether she did this daily, or whether this was a special effort for us on the Christmas Count. She was not a native English speaker and a bit hard to understand; but she was devoted to animals. A friend of mine drove up with a van full of birders on a field trip he was leading; he actually recruited her as a NJ Audubon member, when she found out they had come out of their way to see "her" birds. She also rescued burros and emus and various other critters, which I don't suppose are still around either. It was quite an adventure to visit the farm and I remember those Christmas Counts in great detail.
I am not sure of the date that the Black Vulture nest was found at Cradle Rock. I believe it was around 1990. I hiked in with a friend after hearing the report, and we found a smelly cave with an adult Vulture, standing on a rock, which hissed at us. We did not want to disturb things further and didn't see a chick at that time. 
Here are the numbers from the Princeton CBC:

The only other thing I can offer about Princeton Vultures is that they used to love to sit on the water tower that was behind the YWCA and Merwick, on Paul Robeson Ave. They caught the morning sun in winter on their outspread wings. Promptly at the Spring equinox they'd disappear until next fall. My assumption has always been that the equinox was their trigger to start looking for a nest site. When I lived at Stanworth I enjoyed seeing them every day and took note of their disappearance. These guys were probably close enough to also be a splinter group from the big Coventry roost.
PS Vultures were not the only "good" birds from Coventry farm. In 1994 a flock of gulls was attracted to the barnyard on CBC day, and Jim and I were astonished to find the count's first Lesser Black-backed Gull among them, as well as only the third Iceland gull ever.

Friday, August 25, 2017

Walking Tour of Leaf Sculptures at Graeber Woods


Artist Susan Hoenig, known for her environment-themed artwork and instruction at the Arts Council of Princeton, will lead a tour of leaf sculptures she created at Graeber Woods. The sculptures are shaped like the leaves of the tree species they are situated under.

Bunker Hill Environmental Center is located at 287 Bunker Hill Road in Griggstown, Franklin Township, N.J., about 9 miles down the Millstone River from Princeton.

Tours will be on Saturday, August 26, and Sundays October 1 and 22. All tours begin at 2pm.

You can read more about her artwork and its environmental connections in this article entitled Connecting Earth and Art.




Monday, August 21, 2017

Eclipse Bathing


I got an unusual suntan today. It will all probably wear off in a week or two, but I have to say, the eclipse was transformative, even without making the trip to see totality.





It was a day when some of the world's greatest telescopes were trained on the sun. Okay, maybe this cereal box wasn't one of them.


My dad designed great telescopes (Twins! What a surprise!) on Las Campanas in Chile, so that kind of took the pressure off for his offspring.

Still, the performance of the cereal box with a pinhole was, in my view, subpar. It was time to put on a thinking cap. Fortunately, I'd read an email from the Princeton Public Library, earlier in the day, with a link to Neil Degrasse Tyson's alternative approach. Use a colander, he said.

At first, it didn't seem to be working. I wasn't seeing anything special, though I began feeling an inexplicable craving for those pecan crescents my mom used to make at Christmas time.

Then came the eureka moment. Let the colander cast a shadow on the patio stones.


How cool is that? A whole bunch of crescent pastas bloomed on the ground. Yum!


Leo was suspicious, and gave it a sniff.

But I wasted no time, doing what any normal person would do in the presence of a rare celestial event: shoot a selfie. That's me trying to compete with the eclipse's many-smiled head while on our summer vacation in the backyard. You won't believe the deal we got on a hotel room.

To save time--the eclipse's visit being so brief--I shot a photo of the colander while my shadow shot a photo of the colander's shadow. That's my younger daughter's shadow assisting.


Here's the eclipse posing with its grandfather,



and with Leo.





An obit of my dad says that in 1945 he traveled to Canada with theoretical astrophysicist and future Nobel Prize winner Chandresekhar, to photograph a total eclipse of the sun. They published the photos they took there in a scientific paper.

Sometimes I look up towards the sky and wonder what he'd think of his son's life orbit. He pointed his cameras skyward, but the images had gravitas. I'm more apt to point a camera at the earth, even when the subject is an eclipse, finding levity on the ground rather than gravitas in the heavens.

It all works out, I guess, especially after this weird tan wears off.