Premier Warbler Weekend

Ovenbird (Seiurus aurocapillus) Image courtesy of Audubon

What a great spring weekend!  On Saturday morning, May 10, I accompanied the dedicated group of birders that frequents the Pennypack Preserve for their annual Spring Bird Count.  We were out in the field for 4-1/2 hours, during which time we tallied 65 species (and I got a bit of a sunburn when the sun came out from behind the clouds during the last two hours).  Included in the list were 13 species of warblers; they were the main reason that I went on the bird walk because the warblers are only here for a few days each spring and fall during migration, and I get "rusty" on my identification skills.  The birders all proclaimed this year to be one of the best years for spotting warblers in decades.


A list of the birds we spotted during the Count is posted on the kiosk near the Visitor Center.  The same information can be accessed on the Cornell University Laboratory of Ornithology's e-Bird website.

Actually, my great "weekend" began one day earlier.  As I was scooping birdseed from my storage can in preparation for filling my feeder early on Friday morning, I heard a terrific "thwump" on the window behind me and knew instantly from that sickening sound that a bird had flown into the window.  I thought it was probably one of the Blue Jays that had been at the feeder a minute earlier fleeing from a hawk. But no, it was an Ovenbird, an aberrant warbler that looks like a tiny thrush (see image, above).  Fortunately, the bird was just stunned (and not killed) from the impact, which allowed me to gently lift it off the ground and give it a good inspection - including the orange cap that is almost never visible in the field.  I placed the bird back on the ground and 15 minutes later, when I went outside again, it flew off.

Submitted by
David Robertson, Executive Director

Stocking Up on Trout in the Preserve

Spring is finally here! At least that's what the calendar is saying, but my experience working outdoors tells me another story all together. Either way, we have seasonal spring activities to look forward to: Easter egg hunts, spring wildflowers, the annual Pennypack Creek Clean-up and (my personal favorite) the opening day of trout season. Saturday, March 29, 2014, is the opening day of trout season for 18 southeastern Pennsylvania counties, while the rest of the state will open April 12.

Stocking trout...rather unceremoniously

Across the state all Approved Trout Water streams and lakes have been stocked with farm raised trout. Around Philadelphia we will be fishing for two introduced species: rainbow trout (Oncorhynchus mykiss), native to the Pacific basin (http://en.wikipedia.org/wiki/Rainbow_trout), and brown trout (Salmo trutta), native to Eurasia (http://en.wikipedia.org/wiki/Brown_trout). The waterways around Philadelphia are not appropriate for Pennsylvania’s state fish, the brook trout (Salvelinus fontinalis) (http://en.wikipedia.org/wiki/Brook_trout), due to high water temperatures, unsuitable pH, and competition from non-native fish.

A newly released trout in Pennypack Creek

The section of the Pennypack Creek that runs through the Pennypack Preserve is not public land, so the state Fish and Boat Commission (http://www.fish.state.pa.us/fact_fast_trout.htm) does not stock the creek within the preserve.  Instead, the Trust must rely on volunteers to maintain a fishable trout population. 

Members of Trout Unlimited's Southeastern Montgomery County Chapter

Twice a year Trout Unlimited (TU) Chapter #468 releases 400-500 trout into Pennypack Creek; their most recent release was during the week of March 16. These fish were purchased with private donations and TU membership dues, so please release all trout you catch within the preserve.

Submitted by Gary Snyder

Stewardship Assistant

Field Trip!

Demonstrating the white-tailed deer trap behind the office

Members of the Society for Ecological Restoration's Mid-Atlantic Chapter visited the Pennypack Preserve on Saturday afternoon, March 22, to review forest restoration and white-tailed deer research projects underway here.  This field trip was one of three trips scheduled to coincide with the Chapter's annual conference that took place the day before at Temple University's Ambler Campus.

Dr. Eugene Potapov explaining how he remotely springs the deer trap from his laptop

Dr. Eugene Potapov, a researcher and professor from Bryn Athyn College, began by reviewing the white-tailed deer movement research he and his colleagues have been conducting since 2006 using collared deer and digital telemetry. 

A chapter member from New York City Parks pointing out chestnut blight canker

The group then took a walking tour of The Peak old-growth forest recently cleared of invasive plants, several reforestation projects (including one project that incorporated American chestnut trees, now exhibiting signs of chestnut blight disease), riparian reforestation projects along the Pennypack Creek floodplain, and the 160-acre Raytharn Farm grasslands.  We also took advantage of the fact that one of the tour participants was Dr. James Thorne, a former University of Pennsylvania researcher, who had established a forest succession research project in the preserve in 1990 - a project he had not been back to review in over two decades.

  Dr. James Thorne explaining his research project in the background

Fortunately, the day was partly sunny and warm - the warmest day so far this year, with temperatures in the mid-60s.  I had expected the preserve's trails to be muddy after the endless winter snows, but they were pleasantly firm and dry.  Participants seemed to have enjoyed themselves - even if it was just to have a chance to be outside on a nice spring day.  We even heard spring peepers trilling in Crossroads Marsh!
 
Timing for the tour was fortuitous - there's more snow forecast for tomorrow!

Submitted by:
David Robertson, Executive Director

Down to Seeds and Stems

We've had generous numbers of American Robins (Turdus migratorius) around the Pennypack Preserve all winter.  There are always robins here during the winter, but we seem to have more than the typical number this winter - despite the fact that there's more snow and longer-lasting snow cover than usual.

Because the snow has lasted so long, I (and other birders) have been wondering what the robins have been eating.  Though they are insectivores and carnivores during the growing season, they rely on fruits and berries during the winter.  However, they long ago stripped all the crabapple trees and holly shrubs of their berries.  What's left?

When Mary and I took a walk on Sunday afternoon, I noticed a small group of robins perched in a tree, flitting from branch to branch.  When I pulled up my camera with the telephoto lens, it became clear what was happening: the robins were eating fruits of invasive alien Asian bittersweet.

I knew that robins ate bittersweet arils (along with the berries of invasive Japanese honeysuckle and the hips of alien multiflora rose), which helps to spread the plants, but this is the first time I had seen them in action.  In addition, one of our strategies for managing our preserve is to try to eliminate as many of these alien plants as possible, so I feel a little guilty about reducing the winter birds' food sources.  On the other hand, the birds can always seek food in warmer climes, can't they...

The image above depicts an Eastern Bluebird (Sialia sialis) nesting box adorned with an icicle.  Bluebirds, also thrushes like robins, switch their diet in winter, too, and we host many bluebirds in the preserve as well.

 

Submitted by

David Robertson, Executive Director 

Day of Service to the Forest

 

For the second year in a row, the Pennypack Trust sponsored a Day of Service on the Martin Luther King, Jr. holiday.  Like they did last year, the 15 volunteers who came out to work readied an area for reforestation in the spring by gathering large woody debris into a central location.  The volunteers concentrated their efforts in the wooded 5-acre tract immediately adjacent to the Trust's headquarters on Edge Hill Road.

Woody debris is important in the forest ecosystem, but our degraded woodlands are under siege by invasive plants, and the branches, limbs and logs on the forest floor prevent the land stewardship staff from gaining access to new planting sites.  New plantings need to be kept clear of non-native plants - especially vines.

The former owner of this land planted non-native pachysandra; it's visible in the background as a green "blanket"

So, we've weighed our management options and have made the decision to remove the maintenance obstacles.

Besides, there's always more wood falling from the canopy as the mature trees shed limbs and topple over during storms.  The forest floor won't remain "clear" for long.

Submitted by David Robertson
Executive  Director

At the Edge

Mary and I are having our 25-year-old couches reupholstered and have been working with a fabric and upholstery store located near the mouth of Pennypack Creek.  On Saturday, we went to pick up the finished upholstery, and took a walk along the creek while we were there.

The Pennypack flows south out of the Pennypack Preserve, enters Montgomery County's Lorimer Park, then crosses the line into the city of Philadelphia where it flows within Pennypack Park all the way to its mouth at the Delaware River.  About two miles upstream of its mouth, the creek falls off the hard edge of North America and flows onto sediments deposited on the shallow continental shelf - the Coastal Plain.  The transition from the hard, ancient Piedmont rock so familiar to visitors to the Pennypack Preserve to the sandy Coastal Plain - the fall line - is dramatic.

Pennypack Creek at the fall line

The creek rushes over resistant bedrock and creates a series of rapids at the fall line.  Early European colonists took full advantage of the transition by building a dam on top of the rapids and harnessing the water power for a mill - the most southerly (downstream) of the 28 mills that at one time operated along the creek.  In the image above, the rocky ruins of the massive dam are still in place on the opposite side of the creek, and some of the ruins of the mill are visible as a stone wall in the background.

The Piedmont bedrock at the fall line displays graphic evidence of the repeated stresses experienced by the rock at the edge of the continent.  North America and Africa have collided with one another on at least two occasions, and the bedrock, composed  mostly of dull, gray metamorphic gneiss, is twisted and bent like taffy.  In addition, other types of rock have gotten caught-up in the collisions and been incorporated into the cooled "taffy" like the quartzite in the image above, and the granite in the image below.

A stone studded with mica

Silvery flakes of mica are abundant in some of the rocks.  In the sunlight, the rock above glistened hypnotically.  If I'd been much younger and in an acquisitive (rather than de-acquisitive stage in my life), I would have brought the rock back with me.  The image hardly does it justice.

Fish ladder

A few hundred feet upstream of the fall line, state agencies have constructed a fish ladder in the creek.  Pennypack Creek once was spawning ground for anadromous shad that returned from the ocean to spawn, just like salmon.  With the construction of colonial dams for water power, the shad were excluded from their historic spawning streams and their populations plummeted.  There's an effort to remove dams and restore shad runs in some of their historic streams, including the Pennypack.  This fish ladder was created to allow the shad to swim over a sanitary sewer line partially buried in the streambed; the sewer pipes formed enough of a barrier that the fish could not ascend beyond them, so the Pennsylvania Fish and Boat Commission built this series of riffles and pools.  In addition, they released many thousand hatchery-raised fingerling Hickory Shad into the creek in the hopes that some will return to spawn.

The pools created by this fish ladder have become very popular swimming holes with members of the Hispanic community in the neighborhood.  Although swimming is prohibited, and the creek is far too "impaired" for safe contact, that doesn't stop the kids from cooling off.  Fortunately, if the shad begin to use the creek for spawning again, they would return in March and not have to contend with crowds of kids.

Requisite sycamore-against-blue sky image

Just a few hundred feet downstream of the fall line, the creek is spanned by the oldest extant bridge in the United States: the Frankford Avenue (King's Highway) Bridge, built in 1797.  The King's Highway, constructed during the English colonial period, connected Philadelphia and New York City, and ran approximately along the fall line.  The highway replaced a Native American pathway that traced the same route.  The bridge is a National Engineering Landmark.

The fall line's a pretty "happening" place!

Submitted by David Robertson
Executive Director

Frosty November Morn

 

I awoke on Saturday morning (November 9) to the beautifully frosted native grasslands on Raytharn Farm.  I did my best to capture the crispness before the rapidly rising sun dispelled the magic.

Weedy, non-native foxtail (Setaria spp.) in front of tawny Indian-grass (Sorghastrum nutans)

Rimed thistle rosette and oak leaf

Submitted by David Robertson
Executive Director