Saturday, August 27, 2016

August Bird Disappearance Solved

Two weeks ago, I received an email with the news that the water birds had disappeared from Mountain Lakes Preserve. Might something have been applied to the water to remove algae, with unexpected results, or were geese, ducks and herons simply imitating the general human exodus from Princeton in August? My contacts at town engineering and Friends of Princeton Open Space knew of no chemical applications.

Carnegie Lake, too, was empty of waterfowl, other than a couple great blue herons. One heron flew across the lake, flushed another near the opposite shore, chased it a short distance, then returned across the lake, flying low, its wingtips touching the water.

Smoyer Park's pond also was clear of geese. Had they finally taken note of the signage?

Maybe the fisherman's dog had scared the geese away.

The dog, upon closer inspection, turned out to be 2-dimensional, a metal dog profile placed there by the company contracted to periodically (futily?) scare the geese away. The fake dog looked to be faking out the geese, but the fisherman was skeptical, and told me the geese will soon be back.

Some responses from people in the know, plus some internet research, helped make sense of it all.

Plainsboro Preserve director Nancy Fiske forwarded a response from Scott Barnes, head of New Jersey Audubon's All Things Birds division:
"Most waterfowl tend to molt in late summer and are flightless for a brief period of time, during which they are secretive. I've seen typical numbers of geese around locally in the last few weeks; it may just be they've moved of a particular water body in Princeton. Geese will often change habits and feed at night around the full moon. As for herons and egrets, late summer is a time of wandering, where both adults and juveniles will move about from place to place taking advantage of local food sources and concentrations of fish at ponds/lakes with lower water levels."
Stephanie Fox, naturalist with Delaware and Raritan Canal State Park, added, 
"as for Herons, I believe they are still able to fly, but just not so efficiently, so they also try to hide out in less conspicuous areas until they have their full set of flight feathers."
That could explain why the great blue heron seemed to be struggling to stay above water, and perhaps it was acting territorially towards a young whippersnapper encroaching on its part of Carnegie Lake.

For those uninitiated in the ways of birds, like me, some general info about molting is at this link. The distinction between the "sequential molt" that most birds undergo, and the "simultaneous wing molt" characteristic of ducks and geese, can be found here

Thanks to Elliot for alerting me to this seasonal exodus. It would be interesting to find out where the birds go to be safe during molting, and whether it's one place or many.

Friday, August 26, 2016

Towpath Walk This Sunday, Aug. 28, 8:30am

Time for the annual nature walk along the loop trail next to the towpath. We'll meet at 8:30a this Sunday, August 28, along the towpath just west of Harrison Street, where there's a nature trail sign. All are welcome.

We'll catch the overlap between August and September flowers, as JoePyeWeed, ironweed and cutleaf coneflower transition to goldenrods. The wildflowers were getting mowed down until 2006, when I was able to talk DR Canal State Park staff into cutting back on the mowing. The park staff reduced mowing to once a year (less work!), added a broad, well-mowed trail that runs parallel to the main towpath, and the native flora has responded by growing in greater abundance each year.

The nature trail threads through Princeton's closest approximation of an oak savanna, where there are enough openings between trees to allow summer wildflowers to prosper underneath. All of these Hollow-stemmed Joe-Pye-Weeds are facing north, towards a gap in the tree canopy.

We'll see how natural and cultural influences--from canal building to hurricanes--have combined to shape this diverse, dynamic floodplain habitat.

Parking: There are two small parking lots at either end of the Harrison Street bridge. More distant parking is in the Lake Lane area, just off Harrison St. north of the lake, and at a lot on Washington Road just south of the towpath. If you get there late, it should be easy to find us along the trail loop. This link should take you to a map.

Sunday, August 21, 2016

Sensational Year for Floodplain Wildflowers

If only buildings loved this summer's heavy rains as much as these floodplain wildflowers do. Wild senna has never put on a show quite like this.

A variant of Hibiscus moscheutos is turning on the pink.

Joe-Pye-Weed is flourishing.

Just one stalk of a 9 foot high cupplant would be enough for a bouquet.

The cutleaf coneflower and late-flowering thoroughwort combo has turned the backyard yellow and white. And the pollinators are just lapping it up. A number of factors make these lowland wildflowers easy to grow. The soft ground and the exuberant growth of the desired plants makes weeding easy, and the species shown lack the capacity to spread with rhizomes or stolons, making it much easier to keep the garden in balance.

Saturday, August 20, 2016

Capturing Runoff at the Shopping Center

What is soft rush, a wetland species, doing outside the entrance for Ace Hardware at the Princeton Shopping Center? Look up and to the left and you'll see the awning that spills lots of water onto the walkway during rains. The concrete absorbs the impact and the water then makes haste to the bed of rushes, where much of it is absorbed. Pretty clever. Soft rush is evergreen, so should provide some color even during the winter months. We'll see how it weathers the salt and snowplows that stray off course.

Just down from the rushes is a parking lot island. In the past, these islands would have been built higher than the surrounding pavement, and spurned the runoff. But some of the new islands have notches in the Belgian Block curbing where runoff can enter, seep into the ground and feed the plantings.

All of this means a little less of the shopping center's massive, unfiltered runoff goes thundering into Harry's Brook, a few hundred feet away where the brook becomes a brook in Grover Park.

See a previous post that compares the shopping center's parking lot with a more advanced design at Westminster Choir College.

Friday, August 19, 2016

Check Your Viburnums for Imported Leaf Beetle

The list of destructive, imported insects affecting Princeton is getting longer. Most people are aware of the gypsy moth and the Emerald ash borer. Add the Viburnum leaf beetle, which skeletonizes Viburnums in people's yards and in the wild. A post in May last year documented the larva chewing on a Viburnum in Princeton's Harrison Street Park. I killed every larvae I could find, and haven't seen a recurrence this year. But badly eaten leaves on a Viburnum in a friend's yard in nearby Lawrence this summer mark a second sighting, this time with damage coming from the adult beetle.  

Here's what appears to be an adult on a Viburnum commonly called highbush cranberry.

They do a thorough job of it. Completely skeletonized shrubs seen in Pittsburgh years ago were a chilling omen for what could happen throughout the eastern U.S. It should be noted, in this age when so much focus in the news is on intentionally destructive behavior, that the greatest damage to our world is being wrought completely without malice, as insects and diseases hitchhike on transported nursery stock, and the products of combustion slip silently, invisibly from our exhaust pipes and chimneys.

An arrowwood Viburnum (V. dentatum) in my backyard is showing early signs of an infestation. These are two of the most susceptible species of Viburnum. The most striking incidence of arrowwood Viburnum in Princeton is in low woodlands along the DR canal. Despite growing in deep shade, it can have surprisingly showy clusters of white flowers in the spring. Sad to think those spring vistas could become a thing of the past.

If you check any backyard Viburnums you may have and find early signs, you may be able to limit next year's damage with some of the techniques described at this link.

The blackhaw Viburnum, our most common Viburnum in the wild, is less susceptible.

Sunday, August 07, 2016

Native Plants Featured at the Olympics

The Olympic opening ceremonies in Rio included a big surprise. After some spectacular visuals and choreography with a cast of thousands, the stadium darkened and a solitary boy walks across the stage. He encounters, of all things,

a plant, and thus starts a segment on climate change, with maps showing the coastlines of the world that will be swallowed by the ocean, the shrinking ice cap, and a visual conveying the warming atmosphere over the past century.

Most people think of plants as mere ornament and background for human endeavor, but here was a plant, a Brazilian native plant, no less, front and center, drawing the spotlight. It's one of the great paradoxes, that humanity's first line of defense against the planet's greatest threat is not our militaries, but, of all things, plants. They'll never win the 400 meter, or dazzle on the parallel bars, and many kids graduate from high school knowing little about them, but as brilliant chemists that tirelessly eat carbon dioxide, plants have everything to do with winning the marathon to keep our planet livable for generations to come.

And there they were, later in the evening, next to the flagbearer for each nation entering the arena, native plants of Brazil being carried by a child. A whole forest will be planted, with one plant for every competing athlete. Symbolic, to be sure, contrasting starkly with the environmental realities in Rio, but moving nonetheless.

In this photo, the plant fronting the U.S. athletes is a green flash on the right, with Michael Phelps bearing the flag in the background.

It felt like a gamechanger, as if the world is making a pivot and starting to get its priorities straight. That plant in no way compensates for the human combustion-fest of bright lights and fireworks, but at least it's there, with its humble, heroic chlorophyll, unmatched in its chemical prowess, to remind the athletes where their inhales come from and their exhales are headed.

Thursday, August 04, 2016

Before and After the Flood at the High School Wetland

Many have seen the video of the extraordinary flooding at Princeton High School on July 30. As something of a citizen "activator", and high school parent, I'm meeting with school and town to help give momentum to a lasting solution to prevent future flood damage to the school.

I hope the school's basement and performing arts stage prove as resilient as the wildflowers in the ecolab wetland, which happen to be in full bloom. First photo is a "during" shot, showing the Joe-Pye-Weed and Rose mallow hibiscus sitting in five feet of floodwater.

This second photo shows the plants the next day, happy as clams, as if refreshed from a nice long bath.

This is a great time to stop by and take a walk around the perimeter of the wetland, and maybe catch the sunset in the big sky over the ball fields just on the other side of the performing arts wing from the wetland, on Walnut Lane.

Towpath Nature Trail Loop:
Another great place to see these beautiful summer wildflowers is along the nature walk created and maintained by the DR Canal State Park crews. Get on the towpath at Harrison Street and look for the Nature Trail sign. A virtual guided walk can be found here. This link should take you to a map.