Category Archives: Musings & News

An Infectious Enthusiasm For Birds

Musings & News
Tony Bledsoe lecturing at Univ of Pittsburgh, approx 2006 (screenshot from video)

This week I was saddened to learn that Dr. Anthony Bledsoe passed away on Saturday 14 September 2019. His infectious enthusiasm for birds and behind the scenes advocacy will be sorely missed.

Tony Bledsoe was an instructor and lecturer at the University of Pittsburgh for 31 years and such an inspiring teacher that his students rated him “One of the best professors I’ve ever had.” In 2006 he won the Tina and David Bellet Teaching Excellence Award as Outstanding Undergraduate Teacher in Arts and Sciences at the University, voted by the students themselves.

Tony was a friend and a behind-the-scenes advocate for birds at the University of Pittsburgh. I first met him in 2001 when he offered to help me establish a peregrine nestbox at the Cathedral of Learning. Tony read my PABIRDS report about peregrines in courtship flight and knew there was no suitable location for them to nest. I wanted to install a nestbox but had no idea how to approach the University. Tony knew who to call. He worked behind the scenes to find people to champion the peregrines within the Administration. By February 2002, with Tony’s help, the nestbox was in place. Dorothy and Erie raised their first chicks that spring.

Dorothy with first nestling at the nestbox Tony Bledsoe helped establish at the Cathedral of Learning, Mothers’ Day 2002

Tony provided scientific background on peregrine behavior within the University and beyond. In March 2007, when Erie killed an intruder peregrine at the nestbox, he was interviewed by John Tierney of the New York Times for an article about the peregrine fight: Peregrine Smackdown: Stay Away From My Dorothy!

Bright specks in the beam, migrating birds swirl in Pitt’s Victory Lights, 7 Oct 2018, 11:05pm (photo by Kate St. John)

Last fall, as a member of the Board of the Audubon Society of Western Pennsylvania (ASWP), he worked behind the scenes to save migratory birds at the University of Pittsburgh. When he read my blog about the deadly attraction of Pitt’s Victory Lights, he called ASWP’s Executive Director Jim Bonner to urge this as a Board concern. Jim made connections so quickly that by that evening the University of Pittsburgh and ASWP were working together on the solution. (See Hooray! Good News For Birds!) This rapid response would not have been possible without Tony’s phone call.

Tony’s enthusiasm for science and for birds inspired those who knew him. The video below, probably from 2006, shows how committed he was to education and how he inspired students in every class.

Tony’s infectious enthusiasm will be sorely missed.

For more information, see his obituary here.

Inertia

Musings & News
An object at rest tends to stay at rest (photo of Emmalina asleep by Kate St. John)

Today’s post was inspired by my cat Emmalina (Emmy) and a Twitter video.

My cat demonstrates the everyday meaning of “inertia” all the time. She has a tendency to rest and do nothing.

In fact the real meaning of inertia is the resistance of any physical object to any change in its motion, including a change in direction. It applies to both motion and rest.

Inertia in motion explains how our bodies move when we ride in a car.

  • When the car is going in a straight line at constant speed on a smooth road it feels like we aren’t moving. (No change in motion; no resistance to change)
  • Going around a curve, our bodies lean toward the outside of the curve. (Inertia resists change in direction)
  • When the car stops our bodies keep on moving ahead. (Inertia resists change in speed)

This Twitter video shows an object at rest — a dinosaur toy — staying at rest in mid air after the trampoline surface goes down. Then gravity takes over. Pretty cool.

Or this: The water in the balloon remains in its original shape for a moment after the balloon bursts.

Inertia: the water briefly stays in place (animation from Wikimedia Commons)

In everyday conversation “inertia” should probably mean resistance to change. My cat is good at that, too.

(photo of Emmalina by Kate St. John, dinosaur video from Twitter, balloon animation from Wikimedia Commons. Click on the links to see the originals)

96 Million Shade Balls

Musings & News

Early this week YouTube said to me, “Here’s a video you might like.” Maybe you will too.

Crazy as it looks, the Los Angeles Department of Water and Power (LADWP) is happy with the results since they covered their reservoir with 96 million black balls.

LADWP calls them “shade balls” but they used to be called “bird balls.” Yet there’s not a bird in sight. This 12-minute video from Veritasium explains it.

I’ve never seen shade balls in Pittsburgh but I can think of several reasons why:

  • We have much less sun. (fewer sun-induced chemical reactions)
  • Our climate is humid. (less evaporation)
  • Bromates are not the big problem here. (Alas, in Pittsburgh our problem is lead.)

But perhaps I’m missing something. Have you seen shade balls in Pittsburgh? Let me know.

(video from Veritasium on YouTube)

Why So Many Landslides?

Musings & News, Schenley Park
video embedded from WTAE Pittsburgh on YouTube, 22 Feb 2019

31 July 2019

After heavy rains or a spring thaw in Pittsburgh we inevitably see devastating landslides on the news. Why does Pittsburgh have so many landslides and why are they associated with rain or moisture?

The problem is a combination of a particular bedrock and our steep hillsides. Where both are present the location is landslide prone, as shown on the City of Pittsburgh map below. You can see for yourself at the Allegheny County interactive landslide map.

Landslide prone areas (screenshot from Pittsburgh GIS Data Download Page)

The house in the video above was inside a landslide zone on Semicir Street overlooking Riverview Park. Add water and the house fell down the hill!

The bedrock at fault is Pittsburgh redbed, a claystone that disintegrates into smaller and smaller pieces if exposed to pressure when it’s wet. Redbed is usually under pressure because it’s underneath solid rock and overlying soil. Add water to a steep slope and you have a landslide.

This sandstone boulder on the Bridle Trail in Schenley Park was part of the escarpment above it until the redbed layer beneath it gave way.

An old landslide in Schenley Park on the Bridle Trail, July 2019 (photo by Kate St. John)

Here’s a future landslide on the Lower Panther Hollow Trail. This sandstone boulder, high above my head, will fall some day because the slow drip of water over the boulder has disintegrated the underlying redbed. Notice the reddish crumbled stones.

Sandstone boulder is undercut, a landslide waiting to happen at Lower Panther Hollow Trail, Schenley Park, July 2019 (photo by Kate St. John)

I had read that Pittsburgh redbed disintegrates when wet but I wanted to see for myself so I gathered some redbed rocks and ran an experiment.

Thousands of years ago these small crumbles were a much bigger solid rock but water had already acted on them. Will the crumbles disintegrate in the presence of water and pressure? I kept some rocks dry and soaked others for a day. Here’s my experiment.

Add water and pressure to Pittsburgh redbed claystone and … Watch Out Below!

p.s. For a really spectacular landslide, check out what happened to Route 30 in East Pittsburgh in April 2018.

(photos and redbed experiment by Kate St. John, house collapse video embedded from WTAE Pittsburgh on YouTube, map from Pittsburgh GIS Data)

Reflect Light, Stay Cool

Bird Anatomy, Musings & News
Nankeen kestrel in Australia (photo from Wikimedia Commons)

30 July 2019

How do birds stay cool in hot climates, especially when there’s no shade?

A 2018 Australian study in the journal Nature found that some birds can reflect the hottest part of sunlight, the near infrared (NIR) spectrum.

Near infrared is long-wavelength light beyond the red end of the visible spectrum. Though we can’t see this wavelength we can feel its heat. In fact more than half the sunlight that reaches Earth is in the infrared spectrum, as shown in the graph below.

Most of the sunlight that reaches the Earth’s surface is in the infrared range (simplified image from Wikimedia Commons)

Australia is a good place to study cooling techniques in birds because 70% of the continent is hot, dry and very sunny. The Australian study examined museum specimens of 90 species, classifying them by habitat and testing them for their NIR reflectant properties. Two species stood out.

The nankeen kestrel (Falco cenchroides), named for his yellow color (above), reflects near infrared light from the crown of his head. The azure kingfisher (Ceyx azurea) stays cool by reflecting NIR from his chest. Their feathers can reflect NIR because they have rounder barbs and denser barbules.

Azure kingfisher, Queensland, Australia (featured picture on Wikimedia Commons)

Here’s a graph from the study that compares them with two other species.

Graph of four species (image from Reflectivity article in Nature Communications)

The nankeen kestrel and azure kingfisher are at the top of the NIR reflective scale but low reflectors of visible and UV light. The reverse is true of the blueish bird, a male superb fairywren (Malurus cyaneus). He’s great at reflecting UV and visible light, probably because he lives where it’s moist and shady. The great cormorant (Phalacrocorax carbo) doesn’t reflect much light at all.

Interestingly, near infrared reflectivity is more prevalent in small birds because they benefit more for their size. You can’t tell it from the photo but the azure kingfisher is only as big as a sparrow.

Too hot? Reflect near infrared light to stay cool.

(image credits: nankeen kestrel, sunlight graph and azure kingfisher from Wikimedia Commons. Graph from “Reflection of near-infrared light confers thermal protection in birds” at Nature.com, Creative Commons license. Click on the captions to see the originals)

That Would Be My Perfect Flight

Birds of Prey, Musings & News

Falconry birds aren’t pets, they’re partners.

In this short film, Shawn Hayes describes his relationship with birds and how he became a falconer. His co-star in the film is an immature prairie falcon (Falco mexicanus) that he’s working with to orchestrate the perfect flight.

About the bird’s future he says:

The day that I release my bird back out to the wild I know that bird is going to survive. I know that bird is going to go out and probably get a mate and produce other birds in the wild. And I was part of that.

Shawn Hayes, “How One City Man Found His Calling in the Wild”

“Falconry is not a sport, it’s not an art — it’s a way of life.”

(video by Joshua Izenberg on the National Geographic YouTube channel)

What Is Hope’s Legacy?

Musings & News, Nesting & Courtship, Peregrines
Terzo and Hope with 2 chicks, 3 eggs, 23 April 2019, 3:35pm (photo from the National Aviary falconcam at Univ of Pittsburgh)

Every year Hope, the mother peregrine at the Cathedral of Learning, kills and eats some of her chicks as they are hatching. Among all the peregrine families on camera this behavior is quite abnormal.

This spring some of you wondered if Hope’s behavior would be passed down to her female offspring. The way to find out is to watch one of her daughters nesting on camera (the behavior cannot be seen otherwise).

Are any of her daughters nesting? Here’s the status of Hope’s fledged offspring:

  1. How many young has Hope fledged during her nesting years so far, 2010-2018? 10 fledglings: 4 at Tarentum Bridge plus 6 at Pitt.
  2. How many of her offspring are banded? 8. (We can only re-identify her young if they are banded.)
  3. Subtract known deaths. Of 8 banded offspring, 3 banded are known dead, 5 banded are presumed alive. (*)
  4. How many of the living are female? 3
  5. How many of her offspring have been reported nesting? NONE
  6. How many of her offspring have been seen anywhere since they left Pittsburgh? NONE

In Hope’s nine years of nesting (2010-2018), she has averaged only 1.1 fledgling per year. None of them has ever been seen again.

By contrast Dorothy, the previous female peregrine at Pitt, averaged 3.0 fledglings per year. (If you don’t count her three elderly unproductive years her average was 3.7.) At least 12 of Dorothy’s kids went on to nest in the Great Lakes region, many on camera. Dorothy has children, grandchildren, great-grands and probably great-great-grands by now. She was a matriarch.

What is Hope’s legacy? So far as we know, nothing. We do know that none of her banded daughters are nesting on camera.

p.s. Hope’s potential of fledglings/year is higher than Dorothy’s. Hope averages 4.25 eggs per year at Pitt; Dorothy averaged 3.93. Hope has fewer fledglings/year because half of her hatchlings do not survive the hatching period.

(photo from the National Aviary falconcam at Univ of Pittsburgh)

(*) Living offspring: We will never know the fate of Hope’s 2 unbanded offspring because we cannot identify them. If they are both alive then Hope has 7 living offspring. Due to the 60% mortality rate among young peregrines, it is statistically likely that Hope has only 4 living offspring from 2010-2018, not 7.

.Details:  Hope: 10 fledgings/8 years = 1.1     Dorothy: 43 fledgings/14 years = 3.0 –or– 41 fledglings/11 years = 3.7

The World In A Water Drop

Musings & News
Spider web at sunrise (photo by Luc Viatour (https://Lucnix.be) via Wikimedia Commons)

If your eyes could focus this closely you’d see that the world through a water drop looks upside down.

Refraction through water also makes rainbows — seen in the spider web above — and optical illusions.

On a chilly damp morning Luc Viatour found a spider web displaying this illusion.

(photo by Luc Viatour (https://Lucnix.be) on Wikimedia Commons. Click on the caption to see the original)