Disappearing Islands in Chesapeake Bay

High tide at Tangier Island, Virginia, 16 Sept 2016 (photo from Wikimedia Commons)

7 December 2022

Sea level is rising overall about 3 millimeters (0.1 inches) per year due to climate change but Chesapeake Bay is rising even faster than the ocean — as much as 4.6 millimeters per year — because the area is still subsiding after the last Ice Age. Some Chesapeake Bay islands are disappearing.

NASA’s Landsat images of lower Chesapeake Bay from 1999 and 2019 show how much land has been lost in only 20 years. In 1999 there were white sand beaches on the island edges. By 2019 the beaches are gone and Great Fox Island in the center of the image has almost disappeared.

Satellite imagery from “Great Fox is Disappearing” NASA Landsat Image Gallery

The Chesapeake Bay Foundation used to hold in-residence educational programs on Great Fox (also called Fox Island) but in October 2019, with only 34 island acres left, they declared the end of the program. You can see why in the video below.

Just across the Virginia line (at the bottom of the satellite images) is Tangier Island whose land mass has shrunk 67% since the 1850s. Its population shrank as well. By now Tangier has only 345 acres and a population of about 470.

Residents are routinely flooded during the highest tides, pictured at top and below.

Tide water floods yards on Tangier Island, Virginia, Sept 2016 (photo from Wikimedia Commons)
Tide water floods streets on Tangier Island, Virginia, Sept 2016 (photo from Wikimedia Commons)
Tidewater rising in the yards at Tangier Island, Virginia, Sep 2016 (photo from Wikimedia Commons)

A 2015 analysis by the U.S. Army Corps of Engineers predicted that Tangier Island will become uninhabitable within 25-50 years, about mid-century.

The harbor channel, Tangier Island, Dec 2011 (photo from Wikimedia Commons)

Tangier Island will eventually join Great Fox Island under the bay.

For more information see Great Fox is Disappearing at NASA’s Landsat Image Gallery, Wikipedia’s Tangier Island account and this April 2022 NBC News video about Tangier Island.

(photos from Wikimedia Commons and NASA Landsat Image Gallery; click on the captions to see the originals)

Crows Can Think Recursively

American crow (photo from Wikimedia Commons)

6 December 2022

We humans used to think we were very special and very smart because we had language while other species did not. When we learned that other animals had language too our hubris diminished slightly but we still believed in our uniqueness: We were the only species that could think recursively.

In The Recursive Mind (Princeton University Press, 2011) Michael C. Corballis describes “a groundbreaking theory of what makes the human mind unique.”

The Recursive Mind challenges the commonly held notion that language is what makes us uniquely human. In this compelling book, Michael Corballis argues that what distinguishes us in the animal kingdom is our capacity for recursion: the ability to embed our thoughts within other thoughts. “I think, therefore I am,” is an example of recursive thought, because the thinker has inserted himself into his thought. Recursion enables us to conceive of our own minds and the minds of others. It also gives us the power of mental “time travel”—the ability to insert past experiences, or imagined future ones, into present consciousness.

Princeton University Press Book description: The Recursive Mind

Our uniqueness suffered another blow last month when a study published in Science Advances revealed that crows can think recursively, too.

What is recursive thinking and how did crows prove they can do it?

Recursive thinking means “embedding thoughts within other thoughts” like nested Russian dolls.

Nested Russian Matryoshka doll (photo from Wikimedia Commons)

For instance, my sentences are often recursive. If you put parentheses around the complete embedded thoughts they can be thrown away without hurting the sentence. As in: “Our uniqueness suffered another blow last month when a study (published in Science Advances) revealed that crows can think recursively, too.”

To test the birds researchers trained two crows to peck pairs of brackets in a center-embedded recursive sequence. They used differently shaped brackets, some in proper order, some not. Like this:

[ { () } ] or { ( [ ) } ]

The brackets make my head hurt. It’s easier to see in this diagram.

If you put brackets around the starting and ending “thoughts” you’ll see a pattern. The brackets fail in the non-recursive example.

According to Scientific American, after the crows were trained to peck bracket pairs, the researchers tested the birds’ ability to spontaneously generate recursive sequences on a new set of symbols. The birds were successful about 40 percent of the time, on par with 3 to 4 year olds in a 2020 study. The crows were better than monkeys who needed extra training to reach that level.

So another unique human trait is toppled by Corvids.

Hooray for crows and ravens!

p.s. Not all the scientists agreed with the study’s conclusions. Read more at Scientific American: Crows Perform Yet Another Skill Once Thought Distinctively Human.

(photos from Wikimedia Commons, diagrams by Kate St. John. Click on the caption links to see the originals)

Help Me Find Pittsburgh’s Winter Crows

Crows gathering at dusk in Schenley Park, 21 Jan 2017 (photo by Mike Fialkovich)

5 December 2022

For the past several years I’ve counted Pittsburgh’s winter crow flock for the Christmas Bird Count. Some years I’ve counted as many as 20,000 but last year was a bust. Steady rain, fog, and the fact that the crows moved their roost just before the CBC meant I counted only 220. Aaarrg!

I will not be foiled again this year but I need your help. Where are the crows settling for the night? If you know where they are overnight or after sunset, leave a comment to let me know.

I say “overnight or after sunset” because crows make a big noisy deal out of gathering in large numbers on their way to the roost. Hundreds stage at the tops of trees and shout as more come in. When the sky darkens, they fall silent and leave. For where? That’s the question!

Where are they roosting? (photo from Wikimedia Commons)

Last weekend I tried to find them. By 5:00pm on Saturday 3 December I was sure I’d found the roost by watching from Mt Washington at the Mon Incline (my vantage point is the pink V on the map below). Crows staged in the trees in The Saddle on Sycamore Street, then left for a tree-filled hillside near Kirkpatrick Street below Oak Hill, marked in yellow 12/3/22. I counted about 7,500.

Yesterday I went back to Mt. Washington, confident they’d do the same thing and I was wrong! They didn’t gather in the The Saddle; they didn’t roost at Kirkpatrick. Instead they gathered in the Hill District above Bigelow Boulevard. I could barely count 2,000. As I drove home I saw thousands over Bigelow Boulevard but couldn’t count while driving. Aaarrg! My guess at their location is marked in yellow 12/4/22.

Did they end up near Heinz Lofts along the Allegheny River or on Troy Hill as they did a few years ago? (See orange blocks and question mark.)

Locations of Pittsburgh’s winter crow flock on Dec 3 & 4, 2022 at 5pm (mark up screenshot from Google Maps satellite view)

This year Claire Staples and I will count crows together for the CBC on 31 December but I fear the crows will foil us again.

Do you know where the crows are overnight or after sunset in Pittsburgh? If so, please leave a comment with your answer. (We will need this info especially during the week after Christmas.)

p.s. This weekend’s location change can probably be attributed to the weather. Strong west wind vs. weak southwest wind.

  • Sat 3 Dec 5pm: 43 degrees F. West wind gusting over 30 mph. Temperature falling.
  • Sun 4 Dec 5pm: 36 degrees F. SW wind at 6 mph. No wind chill.

(photo and map credits are in the captions; click on the captions to see the originals)

Dolphins Just Wanna Have Fun

Northern right whale dolphin, Monterey Bay, Calif. 30 Nov 2022 (photo by Robin Agarwal via Flickr Creative Commons license)

4 December 2022

Dolphins are very intelligent and engage in many kinds of play. Robin Agarwal photographed their antics while on a pelagic tour in Monterey Bay on 30 November 2022. For instance …

The northern right whale dolphin (Lissodelphis borealis) in mid-leap, above, looks super sleek because he has no dorsal fin.

A Pacific white-sided dolphin, below, went way beyond mere jumping. He leapt, turned, and sometimes entered the water tail first. Somersaults!

Dolphin somersaulting! Pacific white-sided dolphin

Here’s a calmer view of this species (Lagenorhynchus obliquidens) with a cape of bubbles from his spout.

Pacific white-sided dolphin surfaces with a cap of bubbles on its back, Monterey Bay, Calif, 30 Nov 2022 (photo by Robin Agarwal via Flickr Creative Commons license)

Another favorite dolphin game is to ride the pressure wave at the front of a fast moving boat. Called “bow riding,” the bow wave pushes dolphins fast forward without any flapping on their part.

Dolphins like this game so much that they rushed toward the whale watch boat. Robin Agarwal says of this photo, “Pacific White-sided Dolphins and Northern Right Whale Dolphins stampeding towards the boat to bow ride – my favorite sight in the world.”

Dolphins stampede toward the whale watch boat in order to bow ride, Monterey Bay, Calif. 30 Nov 2022 (photo by Robin Agarwal via Flickr Creative Commons license)

Here they are bow riding with an “unusual swirl color morph” among them.

Unusual ‘swirl’ color morph Northern Right Whale Dolphin joins the other NWRDs and Pacific White-sided Dolphins at the bow

Dolphins just wanna have fun!

Check out the great photos by Robin Gwen Agarwal on Flickr.

(photos by Robin Gwen Agarwal on Flickr Creative Commons license.)

Start Counting! Christmas Bird Counts Coming Soon

3 December 2022

Gloomy, windy weather has chased us indoors but there’s fun ahead in the coming weeks. Join Audubon’s 123rd annual Christmas Bird Count (CBC), Wednesday 14 December 2022 to Thursday 5 January 2023.

Date span of the 2022 Christmas Bird Count (calendar images from timeanddate.com)

During the Christmas Bird Count, volunteers count birds in more than 2,500 count circles in North America. Each circle is 15-miles in diameter and has its own compiler who coordinates the count for a single scheduled day.

You can go birding outdoors or count birds at your feeder (if your home is in a count circle). No experience is necessary. The only prerequisite is that you must contact the circle compiler in advance to reserve your place.

Choose a location and date that suits you from the national map at audubon.org and follow the instructions here for singing up. (NOTE: To see the date of your chosen CBC you may have to scroll down in the little block that shows the compiler’s name.)

If you live in the Pittsburgh area you may be interested in one of these counts. Click on the map for details.

Screenshot of zoomed-in 123rd Christmas Bird Count map from audubon.org

Join the Pittsburgh Christmas Bird Count on 31 December 2022 (map below). If you’ve not yet made arrangements to participate, or you need more information, contact Brian Shema at the Audubon Society of Western PA at 412-963-6100 or bshema@aswp.org.

Pittsburgh Christmas Bird Count circle (map from audubon.org)

Sign up now! We’ll be counting soon.

p.s. Did you know … ?

  • The Christmas Bird Count is funded entirely by donations. Donate here to support the CBC.
  • The CBC extends into January because it spans 11 days before and after Christmas. The entire count period is 23 days, though I doubt any counts are scheduled on Christmas.

(photo from 2022 Audubon Christmas Bird Count webpage, maps from audubon.org; click on the captions to see the originals)

Robins On The Move

Robins pause in a pine, California, Feb 2019 (photo by Douglas via Flickr Creative Commons license)

2 December 2022

In mid November hundreds, perhaps thousands, of American robins (Turdus migratorius) were in the east end of Pittsburgh but left abruptly when the weather dropped below freezing on November 18th. By the 21st it was 17 degrees F and the robins were long gone.

Robins can cope with cold weather but not with frozen ground so they stay just south of the freeze line as winter approaches.

American robin, Marin County, 16 Nov 2022 (photo by Robin Agarwal via Flickr Creative Commons license)

Those that nest in Canada and Alaska may leapfrog over the local slowpokes who wait for truly awful weather.

eBird distribution maps for June-July and December-February show that robins vacate the north to populate temperate zones in winter. June-July is dark purple with robins everywhere. In Dec-Feb they concentrate in the Pacific Northwest and northern California and in the U.S. southeast all the way to Florida.

Robins were on the move here in November. Now they’re south of us, wrapping up.

(photos by Robin Agarwal and Douglas on Flickr via Creative Commons license; click on the captions to see the originals)

Seven Years After Dorothy

Dorothy at the Cathedral of Learning, 5 March 2012 (photo by Pat Szczepanski)

1 December 2022

Seven years ago this week Dorothy, the peregrine matriarch at the Cathedral of Learning, permanently disappeared and was replaced by “Hope” a bird that had formerly nested at the Tarentum Bridge. (Click here to read about the changeover.)

Dorothy was the bird that got me hooked on peregrines. By December 2015 I had watched her for 14 years and was not surprised she disappeared because she was elderly and in ill health. It was hard to watch Dorothy’s decline. She had been so vibrant in her prime.

Much has changed in seven years. Dorothy’s successor was a grave disappointment but Hope’s successor, Morela, is as queenly as Dorothy herself. We are lucky to have her.

Today in a trip down memory lane here’s a video tribute to Dorothy.

The key to Dorothy’s long life may have that E2 was such a good mate.

p.s. Hope turned out to be Hopeless but that’s a story for another day.

(photo at top by Pat Szczepanski in 2012)

Panther Hollow Lake on Hold

Panther Hollow Lake flooded with ice, 25 Feb 2022 (photo by Kate St. John)

30 November 2022

Panther Hollow Lake in Schenley Park has had problems for decades but there was hope they would be solved by an ambitious 2016 plan to rehab the lake and daylight Four Mile Run downstream. Unfortunately the plans were so ambitious that they had to be put on hold this month.

The lake’s problems are legion. It is really only the size of a pond and is filled with sediment. The shallow water cannot replenish fast enough so algae blooms in summer; sometimes fish die. Its unnatural concrete edges prohibit lakeside vegetation that could absorb water and it does not flow into any creek or river. Instead Panther Hollow Lake dumps 68 million gallons per year of clean water into a sewer pipe.

The sewer pipe is what used to be Four Mile Run plus lots of sewage. When there’s not much rain the pipe carries its contents to the water treatment plant at Alcosan.

6.2.3 M29 Four Mile Run: Green Infrastructure Concept Plan Figure 6-15 from pgh2o (markup added for 4 Mile Run)

But in a downpour the pipe is overloaded and floods the downstream neighborhood called The Run.

Combined sewer overflow flood in The Run, August 2016 (photo by Justin Macey used by permission)

In 2016 Pittsburgh Water and Sewer Authority’s Draft Green Infrastructure Plan (PWSA at pgh2o.com) proposed dredging the lake, removing the concrete surround, and building a new dam so the lake would be a good depth.

Concrete edge an algae among the cattails in Panther Hollow Lake, August 2021 (photo by Kate St. John)

It also proposed daylighting Four Mile Run in Junction Hollow — in other words, making it flow on the surface in daylight instead of in a pipe underground. Here’s an example of a daylighted stream in Yonkers.

EXAMPLE OF DAYLIGHTING a stream in an urban setting (photo from Wikimedia Commons)

But when the plans were submitted for approval big problems stood in the way of progress. Here’s what stood in the way, quoted from the PGH2O presentation on 14 Nov 2022 (my comments added).

  • DEP’s review proved difficult
    • DEP would not approve the dam as designed. It had to be much larger to meet current dam codes.
    • Daylighting Four Mile Run in Junction Hollow would be a long permitting nightmare because it must be put back into a (new) pipe to get under the railroad and Second Ave on its way to the Monongahela River.
  • The dam would have to be placed on railroad property and the railroad had already said no.

So PWSA updated the project to solve the biggest problem — flooding in The Run. Described in a public meeting on 14 Nov 2022, the revised project map shows no work in Schenley Park. All work will occur in The Run.

Four Mile Run Stormwater Project (from pgh2o community presentation 14 Nov 2022)

Improvements to Panther Hollow Lake are on hold again. Fortunately the flooding will be solved in The Run.

Read about the updated plan as of 14 Nov 2022 at Pittsburgh Water & Sewer Authority: Four Mile Run Stormwater Project. See the Community Presentation Powerpoint here.

(image credits and links to the originals are in the captions. Maps from pgh2o.com)

The Largest Living Organism is Dying of Deer

Pando in October snow, 2021 (photo by Beth Moon via Flickr Creative Commons license)

29 November 2022

In 1976 Jerry Kemperman and Burton Barnes discovered that 106 acres of quaking aspens (Populus tremuloides) in the Fishlake National Forest of Utah were actually all the same male plant, one root with thousands of suckers that grew into trees. It came to be known as Pando — “I spread.”

Quaking aspen, Pando, in fall (photo from Wikimedia Commons)

Pando weighs 6,600 tons making it the heaviest known organism on Earth and it is very old, though no one is sure whether it’s 10,000 or 80,000 or even a million years old.

Aerial image of the location of the single aspen tree, Pando (highlighted in green) at Fishlake National Forest, Utah (photo from Wikimedia Commons)

However, almost as soon as Pando was discovered researchers found that sections of it were not rejuvenating because new sprouts were being overbrowsed by deer. In that part of the U.S. the species is mule deer (Odocoileus hemionus).

Mule deer in Colorado (photo from Wikimedia Commons)

So they fenced it — twice — one fence in 2013, another in 2014.

Map of 2018 Pando study partially funded by U.S. Bureau of Land Management, Grant/Award Number: L21AC10369 (map downloaded from Wiley Online Library)

Then in 2018 Paul Rogers and Darren McAvoy of Utah State University conducted a followup study sampling Pando’s health inside and outside the deer exclosure fences and concluded that the fencing was not working.

According to September 2022 Sci.News “The unfenced areas are experiencing the most rapid aspen decline, while the fenced areas are taking their own unique courses — in effect, breaking up this unique, historically uniform, forest. … Fencing alone is encouraging single-aged regeneration in a forest that has sustained itself over the centuries by varying growth.”

“One clear lesson emerges here: we cannot independently manage wildlife and forests.”

Sci.News, October 2018: Pando, World’s Largest Single Organism, is Shrinking

Aldo Lepold’s experience in his early career when he worked to eradicate wolves from the American West changed his perspective on trees and deer. At one point he shot an old female wolf and was there to see the green fire go out of her eyes as she died. He wrote …

I thought that because fewer wolves meant more deer, that no wolves would mean hunters’ paradise. But after seeing the green fire die, I sensed that neither the wolf nor the mountain agreed with such a view.…

I now suspect that just as a deer herd lives in mortal fear of its wolves, so does a mountain live in mortal fear of its deer. And perhaps with better cause, for while a buck pulled down by wolves can be replaced in two or three years, a range pulled down by too many deer may fail of replacement in as many decades.

Aldo Leopold: Sand County Almanac, “Thinking Like a Mountain”

Pando’s days are numbered because new trees are not growing up to replace the old ones. This is how a forest dies.

(photos from Wikimedia Commons, map from Wiley Online; click on the captions to see the originals)

Greater and White-Fronted

Greater white-fronted geese from Crossley ID Guide to Eastern Birds (image form Wikimedia Commons)

28 November 2022

Over the Thanksgiving weekend 6 greater white-fronted geese (Anser albifrons) showed up in western Pennsylvania — four in Lawrence County and four in Armstrong County.

Though they breed in the arctic around the world, the North American population stays west of the Mississippi. These geese are rare in Pennsylvania.

Range map of greater white-fronted goose embedded from allaboutbirds.org

Their “greater” and “white-fronted” adjectives don’t make much sense unless you know the species they resemble in Europe.

They are “greater” because they are larger than the lesser white-fronted goose (Anser erythropus) that occurs only in Eurasia and is now Vulnerable to extinction.

They are “white-fronted” because they have white feathers on their faces surrounding their beaks, a field mark that distinguishes them from the similar greylag goose (Anser anser), another Eurasian species.

Greater white-fronted goose (detail from the Crossley ID Guide Eastern Birds, arrow added to indicate white front)

Only a handful of greater white-fronted geese are seen in western Pennsylvania in any given year, and then only in late October through early March.

If you see a goose that resembles this one check its field marks carefully. It may be an odd domestic goose, described here:

(images from Wikimedia Commons, map embedded from allaboutbirds.org)