Outside My Window

We all recognize the Doppler effect when an ambulance siren rises in pitch as it speeds toward us, then drops as it recedes. (Click here for a car horn example.)

Here’s a bird that uses that sound effect.

American avocets have many techniques for protecting their nests from predators.  They pretend to incubate a fake nest, then walk a few steps and pretend again.  They distract the predator by walking toward him in a teetering tightrope walk with wings outspread.  And they mob aerial predators before they can reach the nests.

But the most amazing technique is reserved for ground predators.  When avocets swoop to chase them away they shout at them, modulating their pitch to resemble the Doppler effect.  This is done so convincingly that the predator thinks the bird is approaching much faster than it actually is.  Run away!

Tex Sordahl discovered this while studying American avocets and black-necked stilts in the 1970s and ’80s.  Both use the Doppler sound effect.  I’m sure he got a dose of it during his study.

(photo by Ingrid Taylar via Wikimedia Commons.  Click on the image to see the original.)

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It’s been mulberry season for two weeks now.  In our house it means we take off our shoes.

White mulberries (Morus alba) were imported from China in colonial times in hopes of starting a silk-making industry.  If you import the silkworms and their host, of course you’ll get silk.  Not!  The silkworms died but the trees did not.  They now hybridize with native red mulberry and are considered invasive.

On the plus side, white mulberries produce a lot of fruit for people and birds.  We make the fruit into jams and jellies, the birds lead their fledglings to the trees where they safely sit and eat.

The problem is the fruit is prolific and falls readily from the trees.  One tree in particular shades the sidewalk on our path through Magee Field to Schenley Park.  Right now the sidewalk looks like this.

The fruit is unavoidable even if you walk in the grass.  The berries squish underfoot (quite unpleasant!) and smash into the ridges on the bottoms of our shoes.  The juice stains the carpet if you don’t clean it immediately.

So we’ve adopted the Japanese in-house shoe tradition.  In mulberry season we take off our shoes.

(photos by Kate St. John)

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These inch-long flowers are blooming now in Schenley Park.   They stand out because the plant is three feet tall.

Though penstemons are common in the western U.S. Penstemon digitalis is one of the few species native to Pennsylvania.  I found several blooming in a new location in the park, probably because their seeds were in a native plant mix applied to an erosion project.

Their scientific name is easy to remember.  The common name is a mouthful:  Foxglove beardtongue.   Try saying that three times fast.

(photo by Kate St. John)

p.s. The pistil in this flower looks like a tongue and it has hairs, thus “beardtongue.”

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This morning I got a call from Peter Bell and the news was bad.

Peter had just gotten off the bus to come watch Pitt’s peregrine family but instead of finding E2 and his son in the air, he found Silver Boy’s body in the middle of Forbes Avenue in front of the art museum.  He’d been hit by a car.   One of his parents was on Heinz Chapel steeple, staring at the spot where Silver Boy died.

We got permission from the Game Commission to bury this year’s only fledgling. Peter dug the hole and we said goodbye.

The season’s over.  Silver Boy is dead.

(photo by Kate St. John)

p.s.  please see my comment here.

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June is “air show” month for our local peregrines.  Where the nests have emptied the action is in the air.

After they fledge, young peregrines are dependent on their parents for six to ten weeks while they learn to supply their own food.

Fortunately, as with all predators, they’re born with an instinct to hunt.  Kittens instinctively stalk and pounce.  Peregrines are programmed to chase.  This means they can develop hunting skills without much parental assistance — which is why hacking works.

In their first weeks after fledging, juvenile peregrines chase anything that flies: their parents, their siblings, butterflies, even turkey vultures.

After two to three weeks they begin to focus on prey the right size.  Eventually they capture something, almost by surprise.

In the meantime they play at all the right moves:  chasing, mock dogfights, roll-overs, talon grappling and prey exchanges.

Above a juvenile in Wilmington, Delaware chases his sibling who won the prize.

Keep looking up and you’ll see the air show.

(photo by Kim Steininger.  This Tenth Page is inspired by and quoted from page 501 of Ornithology by Frank B. Gill.)

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While hiking in the Laurel Highlands several weeks ago I heard a hooded warbler alarm call.  I looked for the bird and discovered a large deer browsing in the area of the warbler’s voice.

Though I couldn’t see the warbler I knew why he was upset.  Deer eat birds’ eggs, baby birds and any small bird that can’t fly away.  The deer was as big a threat to his nest as a bear.

Years ago at Powdermill Banding Station I learned that deer are one reason they’re careful to quickly retrieve birds from the mist nets.  If they delay, deer eat the birds trapped in the nets.

In the video above two parent birds try to drive off a buck who’s browsing in the vicinity of their nestling.  The nestling tries to escape but cannot fly well.  The parents’ efforts were to no avail.

Deer are so omnivorous that trail-cam studies have shown they’ll readily eat from carcasses of their own species.

Nature is full of surprises.  Deer are not vegetarians.

(video from YouTube)

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At Pitt:  Our youngster is in the “chase me” phase.  If he had brothers and sisters he’d be chasing them. Instead he chases his parents who willingly oblige.  Above, he dives on Dorothy.  Notice the size difference!  Female peregrines are larger.

Those of us who watch him from the ground are currently calling him Silver Boy in keeping with the tradition of ID-by-color of the USFW band.  (His band has no colored tape; it’s silver.)  When we text each other he’s SB, two initials that happen to include all his previous non-names as well.

Downtown:  There’s been no news of this family since the week they fledged except for this:  Last Friday a dead female juvenile peregrine was found on Grant Street, her body recovered by Beth Fife.  This was one of at least two females hatched at the Downtown nest this year.  We know there were at least two because one female was rescued on May 30 while another was still unfledged in the nest.

If you have any news from Downtown, please post a comment.

I-79 Neville Island Bridge:  These peregrines have been a lot of fun to watch.  At 4:00pm yesterday Laura Marshall reported that all three birds had fledged and were staying up high.  Then at 7:00pm she and Anne Marie Bosynak were standing in the park-n-ride lot when one of the juvie males flew rapidly across the river from Glenfield and tried to land in the bushy trees near them.  This was probably his first encounter with vegetation and he got tangled in the branches.  Like any toddler he called for Mom, picked himself up and apparently tried again on another set of bushes.   His parents merely watched.  Youthful enthusiasm!

Westinghouse Bridge:  Fledge Watch begins tomorrow!

Monaca Bridge:  Last Friday Becky Smith saw two peregrines flying and swooping with each other at the big black railroad bridge.  Their behavior this spring indicates they have young in the nest who may be ready to fly.  Stop by the bridge and see if you can spot fledglings.

Tarentum Bridge:  Though this nest failed Rob Protz reports that the peregrines are still there.  Occasionally he gets a good view of the female.

Green Tree water tank:  This nest failed as well but Mary Jo Peden and Shannon Thompson report that one or both peregrines are visible nearly every time they stop by.  I stopped by on Sunday and saw the female.

Our peregrines are off camera now but they’re really busy.  Check them out at any of these locations.

(photo by Peter Bell)

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Late breaking news!  A healthy young peregrine will fledge from the Westinghouse Bridge this weekend.  Join his Fledge Watch, June 13-18.

This is a Watch we thought would never happen.

When Dan Brauning and Art McMorris visited the Westinghouse Bridge on May 16 the lone nestling was seven days old and appeared to be handicapped and unlikely to survive.  In late May PennDot’s John Kleiber checked on the bird and was surprised to find a healthy, well fed youngster.

Yesterday Dan Brauning and Tom Keller of the PA Game Commission visited again, intending to band the bird, but he was too old to approach.  In Dan’s photo below you can see he’s already fully feathered and might have flown too soon with dangerous results.

Dan estimates this youngster will fledge on or about June 15.

So, yes, there will be a Fledge Watch at the Westinghouse Bridge beginning this Thursday.  John English is organizing the watch and has provided everything you need to know on his website including contact information.

Contact John to coordinate your visit.  Check his website or Pittsburgh Falconuts Facebook group for more information.

Happy flying, little bird.

(bridge photo by John English.  Peregrine photo by Dan Brauning, PA Game Commission)

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In good weather this is what Pitt’s peregrines see every day.  From their perspective, the sky is the most interesting part.

We, of course, find the ground more interesting so it takes up most of the picture.

Between our two points of view is the horizon. Notice how the edge is flat, no hills or mountains.

Pittsburgh was the shore of an ancient inland sea (we used to be at the beach!) and our hills are actually erosion cuts into that flat landscape.  The tops of the hills are what’s left of the original shore and they’re all the same height — about 1200 feet above sea level.  Chestnut Ridge, 34 miles away, is the nearest mountain but it’s only 2,119 feet high, easy for birds to cross.

In the valley below the Cathedral of Learning, near the bottom right of this photo, is the Schenley Plaza tent where we sat during Fledge Watch.  To a peregrine we humans are mere dots.

But they probably weren’t looking at us.  They’re more interested in the sky. 

(photo by Chloe Fan on Wikimedia Commons.  Click on the image to see the original.  This photo was taken in 2009 prior to construction of The Porch restaurant.  Can you tell what else has changed? )

p.s. See this comment for news of Pitt’s juvenile peregrine and the comments on yesterday’s blog for news from the I-79 Neville Island Bridge.

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It’s embarrassing to give advice and not benefit from it myself.

Yesterday morning I met Laura Marshall and Gene Henderson for Fledge Watch at the I-79 Neville Island Bridge.

While we watched from the Fairfield Inn lot, Laura described the nest location in the middle of the span and I gave pointers on how to find the fledglings:  “Watch the parents.  They’ll show you where the fledglings are.”

In the beginning both peregrine parents were perched on a bridge abutment on the Glenfield side.  Gene had been over there but they made warning sounds so he left.

The adults stayed at Glenfield a long time and then, in an unusual move, both flew to our side of the river and perched on a similar abutment.  (Here’s Gene’s photo of an adult on that abutment.)

Sometimes the mother bird, Magnum, swooped down to the river and disappeared for a while. Sometimes we heard a juvie whining.

I walked to the Park-n-ride lot with two Fairfield Inn guests but we had to stay back because “Dad” peregrine made warning sounds at our approach.

Did we benefit from these parental clues?  No.

Laura guided me and Tricia McIntyre to the Glenfield side where she has permission to watch the birds on private land.  Magnum was still on the abutment on Neville Island and we saw two juvies walk the I-beam near the nest. None of us had seen the third juvie yet when Laura said, “There’s a peregrine on the piling across the river.”  Ta dah!  It was the third bird. He had fledged!

He was safe from predators on a concrete island eight feet above the water.  His parents visited and demonstrated how to flap away.  He dealt with three people in a fishing boat by shouting and walking away.  (Read about the boat beginning with Mark B’s comment here.)  He was fine.

In retrospect Magnum and her mate showed us exactly what was going on.  I’ll bet their fledgling was on the Glenfield side when Gene was over there — hence their warning.  They accompanied their son when he flew to the Neville Island side and “dad” warned us away.  Magnum swooped down to the piling and we heard the juvie’s calls echo under the bridge.

I should learn from my own advice:  “Watch the parents.  They’ll show you where the fledglings are.”

(photo by Gene Henderson)

p.s.  Fledge Watchers still needed at this bridge!  Click here for directions.

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