Friday, August 31, 2012

Downstream, Part 1

Harper's Run, a tributary in the county park.  I've featured this stream many times, but this may be my first summer image.
A week ago last Saturday (August 25), Kali and I made a six-mile loop hike along the creek downstream of "our" preserve.  Two miles downstream of the southern preserve boundary, the creek flows into a county park, and then on into a Philadelphia city park on its way to its mouth at the Delaware River.  We parked in the county park and walked the streamside path downstream into the city.  Once the creek crosses the city line, it is bordered by two paths, a dirt footpath on its east bank, and a paved bicycle path along its west bank.  We decided to walk the dirt footpath downstream, cross a bridge, and return upstream on the paved bike path.  I'm going to divide my account and pictures into two parts: the views from our walk downstream first, followed by a second post recounting our walk back to the car.  

A beautiful mature oak near Harper's Run; alas, not long for this world.
An old oak alongside the dirt footpath in the Philadelphia city park
Waiting for Scott to take yet another picture
Scarred and abused - oh so typical in the city park
Healing below the graffiti line
The inhabitant was perched at the mouth of the web, but ran for cover when I stopped to capture its image
Feather of a Downy or Hairy Woodpecker (Picoides pubescens or P. villosus) on an American beech log
Near our first road crossing along the trail, we came upon this stagnant stone-walled spring pool.  Fans of the CBS television show Cold Case set in Philadelphia might remember an episode in which a victim was found drowned in a woodland pond.  The scene was filmed at this spot.

Before it was dammed in 27 places during European colonial times to generate water power for milling, our creek historically hosted an anadromous run of shad; the dams quickly put an end to that, since the first dam, built just two miles upstream of the creek's mouth, blocked the creek (and the shad run) in 1697.  Today, only two dams remain in place, the others having been breached by floods or removed intentionally so that shad runs could be restored.  This dam, a very popular recreational and aesthetic feature known locally as "The Falls," is failing of its own accord - the creek is quickly eroding around the east side of the dam.

Significant erosion around the east side of The Falls dam
Throughout the park, there are beautiful native stone bridges and walls. As in so many urban parks in the United States, the city just doesn't have the money to take care of these cultural, historic and aesthetic amenities, and they are disappearing through neglect and vandalism.  This is the rampart wall of a bridge over a tributary called Paul's Run.

View downstream from the Paul's Run bridge
A streamside sycamore with an unusual growth habit
"The Scream" au natural
"The Yelp"
White Wood Aster (Aster divaricatus)
Rock art on a creekside boulder
Mile-a minute weed (Persicaria perfoliata) growing alongside the creek and perforated by imported biocontrol weevils (Rhinocominus latipes).  This annual vine is an invasive alien scourge in the Mid-Atlantic states.
One of my favorite reaches of the creek
A sandy run below the rocky riffle
Just downstream of this point, we crossed a bridge and returned upstream.  Stay tuned...

Thursday, August 30, 2012

Glorious Late Summer

Last evening, Kali had to work an hour late, so I had a chance to have dinner ready when she came in the door.  After we ate, I told Kali that we had to go for a walk to take advantage of the nicest weather so far this side of summer since we were enjoying low humidity, a light breeze , and temperatures in the low 70s.  My ulterior motive, though, was to look for migrating Nighthawks over the grasslands.

For some reason (probably because it was getting late and this was only going to be a short walk), I decided not to take my camera.  Naturally, a big mistake.  We walked out into the beautiful grasslands full of head-high flowering Indian-grass and Purple-top, and approached the top of a hill with exhilaratingly expansive views.  The sun was setting behind clouds and was producing one of the most beautiful celestial displays we've ever enjoyed--but I didn't have my camera.  The image above is borrowed from the Internet, but is remarkably similar to what I would have captured out in the meadows.

And the Nighthawks didn't disappoint.  We counted seven wheedling high up in the sky, joined at a slightly lower altitude by Chimney Swifts.

One phenomenon that I have noticed at the beginning of each autumn is a nightly streaming of perching birds, most of which seem to be American Robins.  As sunset approaches, birds stream across the meadow skies from northeast to southwest.  I believe that the birds are flying to a communal roost for the night somewhere southwest of the preserve, but I have no idea where these hundreds of birds end up.  Scanning from horizon to horizon, there may be a dozen or so birds visible at any given moment.  As some birds disappear in the southwest, their numbers are reinforced by new birds appearing from the northeast.
We've had a Sedge Wren (or pair of Sedge Wrens) in the grasslands for at least two weeks, and its/their continued presence was confirmed by four birders yesterday afternoon.  As I had posted previously, Sedge Wrens are threatened in Pennsylvania, so we're really fortunate to host this species.

Thursday, August 23, 2012

One Trail Twelve Times - August: A Study in Purple

A Monarch (Danaus plexippus) nectaring on Joe-pye-weed (Eupatorium dubium)
A Tiger Swallowtail (Papilio glaucus) nectaring on New York ironweed (Vernonia noveboracensis)
August is the purple month, at least here in the preserve's meadows.  Deep purple New York ironweed, while just a bit past its prime, is still going strong, and soft magenta Joe-pye-weed is in its glory, much to the delight of butterflies and bumblebees.

I only had two walkers join me for August's exploration of the Beech Springs Trail last Sunday afternoon, August 19, but my companions were exactly the kind of folks I was hoping to draw for my monthly rambles because one was a wildflower devotee and the other was a  dedicated photographer eager to learn the identities of the plants he was photographing.  The afternoon was overcast and cool, and we enjoyed our 0.6-mile walk so much that we we out for over two hours.

The wet meadows are awash in New York ironweed...
...and Joe-pye-weed
New York ironweed and Virgin's-bower vine (Clematis virginiana)
Danger lurks amid the beauty
More purple...
Pink Wild Bean (Strophostyles umbellata)

Yellows are still common in the meadows, now dominated by several species of goldenrod (Solidago spp.)
Puzzling over the identity of a mint.
A leafhopper poorly camouflaged on wild strawberry (Fragaria virginiana)
Butterfly-weed (Asclepias tuberosa) on the dry upper slopes of the meadow
Red hips of multiflora rose (Rosa multiflora)...
...and large, orange hips of pasture rose (Rosa carolina or R. virginiana)
Halfway through out walk, we entered the mature oak and beech woodland sheltering the eponymous Beech Springs.  Because of the high white-tailed deer density, the understory is dominated by spicebush (Lindera benzoin), which the deer are reluctant to eat.  Nevertheless, the bushes provide lots of fatty fruit ready to fuel the southward songbird migration.
Ripe spicebush drupes
One of the Beech Spring runs
For the first time during this series of monthly walks, the banks of the three spring runs were bare.  The skunk cabbages (Symplocarpus foetidus) that had cloaked the banks since January were gone...or so they appeared until we got closer and saw that next year's plants were already emerging from the black organic muck.

Next year's skunk cabbage sprouts (and one of last year's decomposing fruiting bodies) in the spring run.
A hickory (Carya spp.) fruit partially stripped of its husk.  Perhaps a squirrel was interrupted by one of Red-tailed Hawks (Buteo jamaicensis) that regularly patrols the woods.
Once through the woods, we returned to dry meadows where common milkweed (Asclepias syriaca) seed heads were ripening amid the goldenrods.

Galls of two sorts on goldenrod
Wild Potato-vine (Ipomoea pandurata)
The flowering dogwoods (Cornus florida) at the edge of the meadow were already showing distinct signs of the approaching autumn.

The final leg of the trail winds through an allee of huge, mature white pines (Pinus strobus) planted in the 1920s.  They've been there so long, they've laid down a thick duff of fine needles that supports all sorts of mushrooms.  I expect we'll see more variety next month, typically the best month for hunting for fungi.

Probably Yellow-ocher (or Firm) Russula (Russula ochroleuca)
The "one that got away":  my best image of the day might have been one of an Eastern garter snake curled up and snoozing on some dense meadow vegetation about three feet above the ground.  However, when I called my walking companions over to see the snake, it uncurled and slithered away.  I could have kicked myself for not taking a picture first.

Monday, August 20, 2012

Autumn Harbinger

Common Nighthawk (Internet image by Bill Schmoker)
It's not here yet, but when the Common Nighthawks (Chordeiles minor) make their evening appearance over the preserve's grasslands, autumn cannot be far behind.  I keep a close watch on the sky over the fields as dusk approaches this time of year, and last evening was rewarded with a single nighthawk - the first of the season.

It's not like the arrival of the nighthawks is the only evidence of the end of summer.  The Barn Swallows (Hirundo rustica) and Tree Swallows (Tachycineta bicolor) patrolling the airspace over the meadows have been replaced by Chimney Swifts (Chaetura pelagica) (and tremendous numbers of dragonflies, too!).  The foliage of the flowering dogwoods (Cornus florida) is turning decidedly crimson, and the Indian-grass (Sorghastrum nutans), big bluestem (Andropogon gerardii) and deep magenta purpletop (Tridens flavus) are in full flower.

But it's the annual arrival of the nighthawks that clinches the deal for me.

Wednesday, August 15, 2012

Unexpected Meadow Denizen

Sedge Wren at Attwater Prairie-chicken NWR near Houston, Texas (Image by JoAnn Raine, one of our premier birders, who herself migrated to Texas)
One of our expert birders emailed me this morning to inform me that he had spotted a male Sedge Wren - and possibly a female as well - in the tall, native grasslands we have created in the natural area preserve.  He said they could possibly be a breeding pair since the species is known to breed into September.  From my perspective, I suppose they could just as easily be early migrants, as were the Bobolinks (Dolichonyx oryzivorus) that showed up a month early this year.

According to the Atlas of Breeding Birds in Pennsylvania, the Sedge Wren (Cistothorus platensis) is "among the least familiar of all of Pennsylvania's songbirds...rare and local in its distribution."  The book goes on to say that "At the recommendation of the Pennsylvania Biological Survey, the Pennsylvania Game Commission  has listed the species as threatened."

Even if the pair that our birder spotted this morning isn't breeding in our grasslands, it's great to know that the birds are using the habitat we've created as a safe haven during migration.

Monday, August 13, 2012

Saturday, Creekside

While the temperatures were only in the low 80s on Saturday morning, the humidity was nearing double digits.  Nevertheless, fearing a case of air conditioning cabin fever, Kali and I took a walk along the creek.  We came back soaked with sweat ("My clothes are only good for a half-day!" lamented Kali), but more limber for having explored the late summer riparian woods.

We came across a sprawl of dodder (Cuscuta spp.) growing among Green-headed Coneflowers (Rudbeckia laciniata) on the streambank.  The Philadelphia Inquirer did a fascinating story about the New Jersey cranberry bogs a few weeks ago, quoting a farmer who said that he and his crew have to be extraordinarily diligent about controlling dodder or it will kill all of the cranberry plants.  I'm really fascinated by unusual plants like the non-photosynthetic, parasitic dodder, which looks like orange Silly String sprayed on the hapless victims, but the patches that I find are never huge, won't threaten to wipe out the streamside vegetation, and don't appear every year.

Green-headed Coneflowers have come into their own along the banks of the creek as they do each year in August.  I find Asians furtively harvesting the plant's tender basal leaves in early spring and have to stop them because collecting is not permitted in the preserve; their gleaning doesn't seem to make a dent in the population, though.

Another plant coming into its own is porcelain-berry (Ampelopsis brevipedunculata) - my nemesis.  So named because the bright blue, speckled berries reminded people of porcelain doorknobs, this non-native, invasive vine, a member of the grape family (Vitaceae), is the bane of my professional existence.

Come hither, oh ye legions of birds!  Eat me and poop me out everywhere!

My staff has been clearing a thicket over the last week or so.  This doe took advantage of the clearing to gain easy access to the interior, where she might find some particularly succulent sprouts.  One of the things my staff found while clearing the tangle was a stand of a dozen marijuana plants, carefully staked with camouflaged stakes and obviously well tended.  We've set-up a trail camera in the adjacent woodland, but have yet to get a shot of the entrepreneurial farmer.

 Later in the afternoon, we returned to the creek for "Crayfish Catch."  Despite the efforts of thirty or so people in the riffles, we only roused three crayfish (and a Northern Water Snake).  The creek doesn't provide good habitat for crayfish and their ilk; while the water is of high enough quality to support them, the streambed is so full of sediment that it fills the interstices between the rocks and stones.

The winning catch (in terms of size)