A Murmuration

 

Though perhaps I personally notice it more during the warmer months of the year because I'm out later in the day than I am during the winter, one of Pennypack's avid birdwatchers assures me that (even in the winter) every evening just before sundown, American robins (Turdus migratorius) stream toward a wooded area adjacent to but separate from the Pennypack Preserve.  For 30 minutes as the sun is setting, robins streak across the sky - some singly, some in pairs, and others in large, loose flocks of up to 20 birds.  They are all flying toward the southwest.

The birds seem to materialize out of nowhere in the sky because they are flying relatively high, though I know they are just gathering together from scattered locations where they have been foraging all day.  They are silent - black specks all streaming determinedly in one direction.  It's easy to count hundreds of birds in only a few minutes of watching.  If they were all lumped together, it would be a spectacle, but since they're spread thinly in time and space, they constitute more of an imagined spectacle.  Nevertheless, I'm impressed every time I take a late evening walk.

Last week, I was treated to a real spectacle - only the second one I have ever observed in my life.  Looking over toward the roosting forest, the robins were swirling in the air in an amazing cloud of coordinated flying called a murmuration.  It only lasted a few seconds - alas, too short for my wife Mary, who has weak eyesight, to get a fix on it - but I saw it happen and was transfixed for that moment.  

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The Upper Moreland Historical Association's newsletter Moreland Memories recently republished a recipe for pigeon stew that first appeared in the local newspaper's October 18, 1873 edition.  The recipe concludes with the sentence, "Robins are delicious cooked in the same way."  Is it any wonder Passenger Pigeons are extinct?

 

(The images accompanying this post were borrowed from the Internet) 

 

Submitted by David Robertson

Executive Director     

Unabashed Anthropomorphizing

Hooded Warbler (Wilsonia citrina) (Audubon image)

I have begun my annual census of the birds breeding in the heart of the largest, oldest and densest forest in the Pennypack Preserve.  I always begin the census on or around May 20.  This date is a compromise.  For early-breeding resident species like Carolina Chickadees, Tufted Titmice, and the woodpeckers (i.e., Northern Flickers and the Red-bellied, Hairy, and Downy Woodpeckers), they've already fledged their young, which accompany their parents begging to be fed and learning how to take care of themselves.  On the other hand, later breeding migratory species like Wood Thrushes, Veerys and Scarlet Tanagers are still establishing their territories on May 20, making counts this early in the season unreliable.  In fact, most ornithologists caution that migrants in southeastern Pennsylvania should not be tallied until they've settled down into territories beginning in June.

Each year, there are always a few late and errant migrants in my earliest counts.  This year, for example, I heard a Black-throated Blue Warbler on my first foray into the woods on May 19.  Black-throated Blues breed in the Appalachian highlands, New England, and southeastern Canada - they won't stay the summer in our humid lowland woods.  Sure enough, the bird was nowhere to be heard two days later; it had moved on north.

However, on my first counting day, I also heard a Hooded Warbler singing in the forest.  This bird is a furtive wraith rarely observed but much more often heard.  Its call is distinctive and unmistakable: wheeta-wheeta-WHEET-see'o, repeated loudly and incessantly from the dense forest understory where the bird is lurking.  Unlike most other warblers that breed further north and at higher elevations, the Hooded Warbler does breed in southeastern Pennsylvania, though it is rare.  I have only documented breeding pairs in two other years during the 24 years I have been censusing birds in the forest.

This spring's Hooded Warbler stood its ground, singing for 30 minutes while I conducted the census where it had staked out its territory.

Then, when I returned to the woods two days later, the warbler was still present, but it had moved its singing perch over the crest of a ridge and about a half-kilometer deeper into the forest.

All of which got me thinking.  (I have plenty of time to ruminate when I'm conducting the census.)

This poor Hooded Warbler, undoubtedly a male singing its heart out seeking a female, probably is out of luck this year unless it moves somewhere else.  This forest in the preserve, while good habitat, is small and surrounded by suburbia.  If there are no female Hooded Warblers in the forest, the chances of this male finding a mate are nil.  It's not as if he could just fly a few hundred feet further along in the forest to another spot in hopes of luring a mate; if he were to fly a few hundred feet, he'd be in the middle of someone's back yard or in a business campus.

I couldn't help but feel sorry for this seemingly desperate bird - so clearly ready to find a mate, searching throughout the forest but unable to locate a female.  If he does find a female, he'll sing most of the summer defending his territory.  More likely, though, he'll go quiet.  If that happens, I'll never know if he flew elsewhere where his prospects might be better, or if he simply sat out the summer to try again next year, here in the preserve or in another woodland.

If he stays, I'll keep you posted.  For my census, the year is young; for a bird trying to find a mate, the clock is ticking.   

Submitted by
David Robertson, Executive Director

Snowy Cleanup

Executive Director David Robertson with board member Kathleen Ernst

Every year since 1970 when the Pennypack Trust was founded, we have sponsored a volunteer cleanup of the banks of the creek flowing through the Pennypack Preserve.  In fact, the cleanup is the Trust's largest annual event, usually drawing upwards of 100 volunteers who spend two hours hunting for trash and who then return to the headquarters for lunch.

This year's cleanup was last Saturday, April 9.  As the date approached, the weather forecast quickly began to deteriorate, with calls for a wintry mix of wet snow turning to rain.  Yuck!

When I awoke on Saturday morning, the skies were overcast but there was no precipitation falling.  Would we be spared?  However, 45 minutes before the start of the event, I heard on the radio that snow was falling to our west and, sure enough, when I went out to help prepare, snow had moved into the area.

Nevertheless, we did not call off or postpone the event, and about 60 volunteers reported for duty.  I led my group down to the creek (a 10-minute walk via the Rosebush Trail), where we forded the stream to get to an island that is always a hotbed of trash.  This year was no exception.  The creek splits at the head of the island and floodwaters push all sorts of debris up onto the point where the stream divides.  Most of the flotsam is woody, but it also contains all the detritus of modern life - especially plastic bottles and polystyrene.

A "before" picture of trash embedded in woody debris (volunteer at right)

My group's most impressive finds included one natural item (a large, partially decomposed snapping turtle) and one unnatural (a mannequin's arm).

Over the 28 years I've helped with the creek cleanup, it's interesting to note that we hardly ever find aluminum cans any longer (formerly a significant part of the trash collected).  Are more people recycling, or are the cans valuable now?

We decided to call ourselves the Drowned Rats

In any case, though we were wet, all of us had a good, rewarding time despite the weather.  Cleaning up trash is really satisfying.

 

In addition to the volunteers who worked along Pennypack Creek in the preserve, two other groups worked in Upper Moreland Township parks along Round Meadow Run, a Pennypack Creek tributary, cleaning up trash headed downstream from downtown Willow Grove.  We appreciate everyone's help!

 

Submitted by:

David Robertson, Executive Director