Geology Walk, May's Cafe, and Community Collage at Herrontown Woods Sunday, May 3

Though the high ground in northern Princeton known as the Princeton ridge may not live up to the "mountain" in Mountain Lakes and Mount Lucas Road, that igneous upwelling 200 million years ago makes for some fascinating geology underpinning the town. 

On Sunday morning, May 3, at 11am, Laurel Goodell and grad students Theo Green and Josh Isaacs of Princeton University’s Department of Geosciences will lead a geology walk at Herrontown Woods. They'll explain the origins of the many diabase boulders, the presence of magnetic rocks, and other special features. We may even hear about the weather and soil station installed years back at the Barden. In honor of Earthday, the walk will be free.

Preceding the walk, starting at 9:00am, will be the monthly May's Cafe with coffee, tea, and baked treats at the Botanical Art Garden ("Barden") in Herrontown Woods at 600 Snowden Lane. 

Adding to the creativity and fun at the cafe, artist and FOHW board member Hope VanClef will host a workshop, in which participants can decorate tiles that will become part of a Community Collage. Follow the link to sign up.

Another Fish Sighting at Herrontown Woods: Creek Chubs

This post about aquatic life in Princeton begins with a hawk. Spotted and photographed by volunteer Mariah on April 4, about 100 feet downstream of the red trail's stream crossing at Herrontown Woods, it was not soaring or perching on a branch as hawks typically would, but instead was standing very still on the ground at the edge of the stream, peering into the water. 

What was it looking for? My thoughts immediately went to the day we were startled by the thrashing of several foot-long fish as we crossed the stream on that very trail on that very day one year prior. Might predators know its time for the spring migration of fish up into Herrontown Woods to spawn?

Whether due to lack of serendipitous timing, or lower water levels, we saw no return of the foot-long white suckers this year, but yesterday a visitor to the woods named Brian told me he had seen fish down at the stream. 

I went down to have a look, and this is what I found, about six inches long. I tried my best to take some photos before releasing it back into the cool, clear waters that flow from the headwaters preserved within Herrontown Woods. 

Its mouth didn't look as downturned as those on the white suckers we saw last year. What could it be?

Those horny bumps on the head and some internet research led to creek chubs (Semotilus atromaculatus). The bumps are called tubercles, found only on the males during mating season. One cool thing about chubs in general is that the males build nests made of stone, then entice a female to lay her eggs there. The nests can be quite elaborate, and are so well guarded by the male that females of other fish species may take advantage of the free security by laying their eggs there as well.

Googling horns on the head, I had initially encountered a related fish called the hornyhead chub. Who knew that Newborn, Georgia hosts a Hornyhead Fish Festival each year. My respect for the fish, and chubs in general, grew as I read this fascinating account of the male hornyhead's nest building expertise, assembling surprisingly large rocks from the streambed into elaborate structures to protect the eggs.

Such testimonials stir memories of the round depressions sunfish would make in the shallow waters of the lake near Hayward, Wisconsin where my family would journey each spring to set up the tents for a Girlscout camp. It may also be worth taking a closer look in local streams for circular stone structures fashioned by creek chubs.

Film Review: The Little Things That Run the World

The following was written after attending a screening of "The Little Things That Run the World" --a fascinating film about insects and their global decline in number and variety--at the 2026 Princeton Environmental Film Festival (PEFF). There don't appear to be any other reviews of the film online.

As a land manager and gardener who has long catered indirectly to the needs of insects, I emerged from this hour and forty five minute documentary with a deep sense of both gratitude and frustration. The film excels at revealing the beauty and diversity of insects, yet is inexplicably dismissive towards several factors that are likely driving the dramatic decline in their numbers. 

First, some of the many positives. As the film introduces us to the mind-boggling diversity of the insect world, it also provides portraits of a memorable cast of characters who show their steadfast love for insects in varied ways. The film is dedicated to E.O. Wilson, and apparently takes its title from an article Wilson wrote in 1986. In one scene in this documentary, we see the preeminent entomologist in his last year or years, still mobile enough to comb a gentrified suburban landscape with a net, in search of insects to show us. Fittingly for the theme of the movie, he finds none. In the 21st century, I've seen the great environmentalists of our era age while civilization continues stubbornly down its self-destructive path. Wilson provides a dramatic example, his right eye drooped to a close as if part of him really doesn't want to see what's happening to the natural world he has devoted his vigorous life to studying. 

There are so many fascinating human portraits in this film, and so many ways to love insects: by photographing their otherworldly micro-features with a powerful camera, or steadfastly building decades of data on their numbers. Other researchers accumulate countless trays of countless tiny bees all lined up, each skewered with a pin, awaiting someone with the passion and curiosity to study their features. We visit a gardener who gradually dug up his lawn to plant wildflowers until there was no lawn left.

In the film, director Doug Hawes-Davis visits backyards and farms where insects and the plant diversity that supports them are valued and nurtured. Then, with the help of drone photography, he occasionally lifts us up and over the landscape to see how one nature lover's diverse plot of land is dwarfed by the anti-nature world of buildings, roads, and lawns that surrounds it. Vistas of vast almond plantations, sterile country club developments, and corn fields drive home the massive scale of simplified landscapes that have displaced complex nature.

Why does the film visit the almond plantations in California? Because early each year beekeepers truck more than 80% of all U.S. honeybees to one area of California on semi-trailers to pollinate those almond trees. The high quality pollen and nectar from the almond flowers gives the bees an early feast, but the annual mass gathering also serves as a giant spreader event for disease and pathogens increasingly afflicting honeybee populations. We also travel to Germany, where a longterm study using appropriately named Malaise traps documented a 76% drop in insect biomass over 27 years. There are other signs of declining insect numbers. Some species of bumblebees once common in the eastern U.S. have disappeared altogether. Windshields are no longer splattered with insects. 

The movie's website promises insight into cause:

What is causing this extinction crisis? What can be done to reverse the trend? The Little Things that Run the World attempts to find answers to those questions and more.

But it is here that the film falls short. Yes, today's farms and lawns are far larger and more sterile than in the past. Development has usurped and fragmented habitat. But the film barely mentions climate change, and no reference is made to invasive species other than when a few volunteers are filmed naively hacking at a patch of Phragmitis--a manual approach to fighting this pernicious invasive plant that is doomed to failure. Though some pesticides surely play a role in insect decline, the film vilifies them all, including the low-toxicity herbicides that no manager of native habitat could possibly do without--any more than a doctor can effectively practice medicine without medicine. In this way, the film contradicts E.O. Wilson himself. 

The film could have considered other potential causes of insect decline--for instance the increase in the number of deer, whose appetites have erased the varied native understory vegetation that herbivorous insects need to survive. It's worth noting that the film seldom ventures into forests. Deep shade suppresses the sorts of wildflowers and shrubs that can sustain pollinators through the summer months. In this way, the massive succession of the eastern U.S. from fields to dense second-growth forests over the past century may be a mixed blessing.

A lot of environmental threats can be characterized as "too much of a good thing." There's too much carbon dioxide in the atmosphere, too many deer, too many of this or that introduced species. Some types of herbicides, like medicine, can be helpful in small amounts, harmful if overused. There can even be too many trees stealing sunlight from the more diminutive species pollinators need.

Devoting quality time to memorable portraits of people, the film neglected to use its powers of visualization to document important drivers of insect decline: vast stretches of invasive species, a forest understory stripped of native plants by deer, and the stress of increasingly radical swings in weather, be they from deluge to drought or from hot to cold to searing hot again.  While rightly questioning the simplified suburban landscapes that cheat insects of habitat, the film left unchallenged the comforting and crippling environmental orthodoxy that trees are all good and pesticides all bad. 

The film is definitely worth seeing for all its strengths, but the seemingly willful false narrative about cause is reason to follow it with a discussion of all the likely drivers of insect decline left unmentioned.

Related writings:

Reviews of books, articles and opeds denying the threat of invasive species

Lesser Celandine Lookalikes: Which Leaves to Leave

For many people who have a yard to take care of, concern about the ultra invasive lesser celandine can lead to stepping outside to take a closer look at what's growing out there. 

This is a plant that seems pretty at first, then becomes a menace as it spreads through your lawn and flower beds, then into your neighbor's yard and the local nature preserve.

Here's an advanced invasion of a lawn at Pettoranello Gardens.

As you hopefully act to eliminate it from your yard, most practically with a spray bottle in hand, suddenly there's a motivation to distinguish one little plant from another. 

This post will help you make those distinctions between lesser celandine (also called fig buttercup) and other similar-looking plants, and in so doing use as little spray as possible. 

First, a few photos of lesser celandine in its various forms. 

It can have a lot of petals, but unlike dandelions, they are distinct petals.

By mid-April, the flowers are fading away, so take a good look at the leaf. Invasion of your yard begins with little benign-looking clumps like this, here and there. It doesn't look threatening, but this is by far the best time to act.

Lesser celandine will likely be pretty obvious to you, but if you've been eradicating it each year and are down to a few, it's useful to know other plants that look similar. 

Here's garlic mustard. Notice the scalloped, wrinkled look to the leaves, a bluish tinge, and the strong mustardy aroma. Unlike lesser celandine, which has deeply entrenched roots and no clear rosette, you can gather the basal leaves of a garlic mustard in your hand and pull it out of the ground--something really good to do before it goes to seed, because it too can spread and begin to take over. The smaller leaves closer to the ground in the photo are mock strawberry. See below.

Mock strawberry, a nonnative that can spread in annoying ways, via stolons, through your garden and lawn, has a yellow flower, but only five petals. Note the distinctive leaves, which are composed of three leaflets. 

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Dandelions, too, have a yellow flower this time of year, but you'll see that the dandelion flower doesn't have those distinct petals, and the leaves are not round but instead linear and deeply lobed. Dandelions will invade your yard, but not the local nature preserve.

 

Violet leaves are probably the easiest to confuse with lesser celandine. Notice the arc-shaped veins in the leaves, which lesser celandine lacks. The violet leaves may also be duller--less glossy--than the lesser celandine leaves. Violet leaves and flowers, by the way, are tasty in salads or steamed, so its well worth getting to know them.

Here's a typical violet flower.

Scrutinize this photo a bit. Lower down is the lesser celandine, but in the upper right are two leaves that are similar to lesser celandine, but are more elongated and have ribbing on the leaf surface. 

Here's a cluster of leaves of that other plant that isn't lesser celandine. I don't have a name for it yet.

If you happen upon this one, you've found woodland aster, a native that has white flowers in the fall.

Sometimes I encounter a delicate, usually solitary plant whose basal leaves can look a bit like lesser celandine but with a subtly different shape. 

As it grows, it sends up some creatively shaped avant garde leaves and bears some tiny yellow flowers. I have preliminarily identified it as small-flowered buttercup. It doesn't have the robust, dense growth form of lesser celandine. 

These are the lookalikes that I have encountered. Knowing them helps me use as little herbicide as possible, and save the other plants that increase diversity rather than form monocultures of a toxic plant that's inedible to wildlife.

One more photo showing how those first, benign-looking clumps of lesser celandine, if not dealt with early, will continue to spread and merge into one giant mass that looks like green pavement.

A note about herbicides: Many people are reluctant to use herbicide, but a yard is not an organic farm. You can't mulch or cultivate a lawn or flower bed, or a nature preserve, for that matter. The undesired is embedded in the desired, much like infections in your body. You can certainly try to dig up lesser celandine (don't leave any roots in the ground, and throw the diggings in the trash, not the compost), or torch it, or spray vinegar solution. Better results will likely come, however, from targeted, minimalist use of systemic herbicide that kills the roots. It's unfortunate that some have imposed a blanket condemnation on all herbicides, regardless of their individual characteristics. Think of the spray not as poison but as medicine. We routinely use medicines of varied and known toxicities in our bodies. When seeking to heal ourselves, we catch infections early and use as little medicine as possible to get the job done, and it's the same when sparing nature from invasions. The earlier you catch the invasion, the less herbicide needed, so don't delay.

Other related posts:

Will the Real Marsh Marigold Please Stand Up: A Confusion of Yellows