They’re Back!

Crows & Ravens
Crows bursting off a tree along Forbes Avenue (photo by Kate St. John)

17 October 2024

The crows are back in town!

On 1 October I counted 1,800 crows staging in Shadyside before they flew west to a roost. Last night I counted twice as many heading toward the Cathedral of Learning. 3,600 is only a fraction of the flock that will be in Pittsburgh by the end of December. As their numbers grow they quickly wear out their welcome. Then they’ll move the roost.

In transit a flock this large is kind of mesmerizing (video from Dec 2023).

Crows flying toward the roost, December 2023 (video by Kate St. John)

But if they sleep in your trees they are really messy.

Evidence that crows roosted in the trees above this sidewalk, 7 Nov 2020 (photo by Kate St. John)

On Monday I saw Pitt’s maintenance staff spray-washing the sidewalk on Bigelow Blvd and I found “poot” evidence across the street as well. I’m sure Pitt is on the verge of moving them along, if they haven’t already done so.

Last year Pitt used flashing lights to convince the crows to leave the Bigelow Blvd trees. Crows really hate strobe lights.

Pitt works to move the crows, 13 Nov 2023 (video by Phillip Rogers)

I suspect there were strobe lights last night because … When the crows sleep near the Cathedral of Learning I live in their dusk and dawn flyway. Last night thousands flew past my window but this morning none of them made the return journey. So the crows did not sleep at Pitt. I wonder where they went.

This tug of war with winter crows happens every year. They might end up where all can sleep without bothering anyone, or they might split the roost to reduce their impact. One thing I know for sure. The crows will be hard to find for the Christmas Bird Count. 😉

UPDATE 17 Oct, 1:30pm: The crows *did* sleep in the trees at Pitt. I saw the evidence this morning.

Ravens Can Imagine Thieves

Crows & Ravens
Common raven (photo from Wikimedia Commons)

16 October 2024

Did you know that ravens have paranoid, abstract thoughts about other minds?

A new(*) study has found that ravens are able to imagine being spied upon — a level of abstraction that was previously thought to be unique to humans.

— WIRED, 3 Feb 2016(*)

Ravens are well known to cache food but who owns the stash operates on the principle: “Unless another raven is actively guarding it, whatever food I see is mine.” The finder eats or re-hides the cache. We would call this thievery.

To prevent thieves, a raven with lots of food waits until all the other ravens leave before caching his treasure. He’ll even go to a place where no one can see him hiding it.

Scientists thought that a raven had to see another raven before he went to all this trouble. Then a study in 2016 tested whether ravens can imagine potential thieves they cannot see.

The study, published in Nature Communications, found that if a nearby peephole was open, ravens guarded pockets of food against discovery in response to the sound of other birds — even if they didn’t see another bird. This was not replicated when the peephole was closed, despite hearing the same auditory clues.

Ravens are so smart that they can imagine thieves, just like we can. Is it a blessing or a curse to be this intelligent?

Watch how ravens imagine what another raven is thinking in this video from BBC Earth.

video embedded from BBC Earth

A Tomato That Thrives in Salty Soil

Climate Change, Plants & Fungi
Currant Tomato (Solanum pimpinellifolium) at Pantanos de Villa, Chorrillos, Peru (photo by ruthgo via iNaturalist)

15 October 2024

Many crops around the world are irrigated but this inevitably leads to salty soil. Eventually the land becomes useless for agriculture.

Irrigation eventually makes the soil salty: Irrigation rig in Yuma County, AZ, 1987 (photo from Wikimedia Commons)

USDA explains:

What happens when you irrigate?
Irrigation inevitably leads to the salinization of soils and waters. In the United States yield reductions due to salinity occur on an estimated 30% of all irrigated land. World wide, crop production is limited by the effects of salinity on about 50% of the irrigated land area. … Concern is mounting about the sustainability of irrigated agriculture.

Where does all the salt come from?
Application of irrigation water results in the addition of soluble salts such as sodium, calcium, magnesium, potassium, sulfate, and chloride dissolved from geologic materials with which the waters have been in contact. Evaporation and transpiration (plant uptake) of irrigation water eventually cause excessive amounts of salts to accumulate in soils unless adequate leaching and drainage are provided.

— USDA Agricultural Water Efficiency and Salinity Research Unit: Riverside, CA: Frequently Asked Questions About Salinity

Salt residue makes the soil hostile for everything, even weeds.

Salty residue after irrigation water percolated up and evaporated, 2011 (photo from Wikimedia Commons)

This worldwide problem will get only worse as climate change increases drought, so a team of researchers looked for salt tolerant crops.

Focusing on the tomato’s closest wild relative, the tiny currant tomato (Solanum pimpinellifolium), they selected “over 2,700 cultivars, raising the seedlings in two environments: a greenhouse, and an open field.”

The best results came from five cultivars from Peru.

Currant tomato flowers in Lambayeque, Peru(photo by jackychj via iNaturalist)
Currant Tomato (Solanum pimpinellifolium) at Los Pantanos de Villa near Lima, Peru

What genes do these plants have that make them thrive? That’s a question for the next study.

Read more in Anthropocene Magazine: A tiny tomato may harbor the secret to salt-tolerance in a climate-changed world. “The closest living wild relative of the common tomato holds untapped genetic secrets thanks to its large diversity.”

Which Birds Will Visit This Winter?

Migration
Two evening grosbeaks in flight, western Washington State (photo from Wikimedia Commons)

14 October 2024

When North Americans go south for the winter they do it to escape the cold. When boreal finches leave Canada in autumn it’s not about cold, it’s about food.

Winter finches are cold hardy and could stay up north all year but when seed cones and fruit are in short supply they fly south to find food. Every year the Finch Network examines finch food crops across Canada and predicts southward movement by species. Their 2024-25 Winter Finch Forecast came out in late September, summarized below.

This winter we will NOT see these species.

  • Pine grosbeaks (Never come to southwestern PA anyway.)
  • Redpolls
  • White-winged crossbills
  • Red crossbills
  • Redpolls (It feels like a very long time since redpolls came to PA.)
  • Bohemian waxwings (Never come to southwestern PA anyway.)

But we may see …

Purple finch (Haemorhous purpureus)

Purple finch (photo by Chuck Tague)

This year, the majority should leave Canada with a likely moderate flight to the Great Plains and southern United States. … At feeders, they prefer black oil sunflower seeds.

— 2024-25 Winter Finch Forecast

Pine siskin (Spinus pinus)

Pine siskin in Quebec province (photo from Wikimedia Commons)

Areas from Manitoba eastward affected by Spruce Budworm infestations have a poor cone crop. Siskins that bred in these areas will be on the move. While band recoveries show siskins will move straight across North America from coast to coast, there should be some small movement south in the eastern half of the United States this fall in search of food. 

— 2024-25 Winter Finch Forecast

Evening grosbeak (Coccothraustes vespertinus)

Evening grosbeak, January 2013 (photo by Steve Gosser)

Spruce budworms caused problems with the cone crop this summer but there were lots of berries. However, the berries gone now so…

Evening Grosbeaks should visit areas from the Maritime provinces south towards Pennsylvania. Areas even further south to the mid-Atlantic states may see grosbeaks this winter.

— 2024-25 Winter Finch Forecast

These species are not finches, but are part of the prediction.

Red-breasted nuthatch (Sitta canadensis)

Red-breasted nuthatch (photo by Chuck Tague)

Because of patchy balsam fir cones, there should be a moderate to strong flight of red-breasted nuthatches into the U.S.

Blue jay (Cyanocitta cristata)

Blue jay at Frick Park (photo by Charity Kheshgi)

In eastern North America westward to Manitoba the deciduous tree crop (they love acorns on oaks) appears below average with scattered areas of average crops, so expect a moderate to strong flight this fall. 

— 2024-25 Winter Finch Forecast

I’ve already seen lots of blue jays passing through!

Double Flip the Tennis Racket in a Single Toss

Musings & News
Tennis racket photo from Wikimedia Commons

13 October 2024

When I saw this NASA video of a spinning T-handle flipping in zero gravity it blew my mind. Does this weird flipping behavior happen only in outer space?

NASA video posted by Plasma Ben

As it turns out you can do it at home with a single toss of a ping pong paddle, shown below in slow motion by Dr. Dan Russell …

video by Dr. Dan Russell, PSU

… or various tennis rackets.

The physics behind it is called the Tennis Racket Theorem or the Intermediate Axis Theorum or the Dzhanibekov effect, named for Russian cosmonaut Vladimir Dzhanibekov who saw it in outer space in 1985.

Naturally it is quite impressive in outer space as the object stays suspended while it flips!

Learn about the science, physics and math in this 14+ minute video: The Bizarre Behavior of Rotating Bodies, including why the Russians kept Dzhanibekov’s outer space discovery secret for 10 years.

Seen This Week

Phenology, Plants & Fungi
Sun rays through the mist, Schenley Park, 4 Oct 2024 (photo by Kate St. John)

12 October 2024

This week’s biggest Seen event was the aurora borealis which I wrote about yesterday (Northern Lights Last Night in Pittsburgh), but there were also subtle changes in the landscape that prompted a few photos.

Cold weather brought foggy mornings and sun rays burning through the mist in Schenley Park, at top.

It’s a big mast year for Schenley’s red oaks. These shallow, tightly scaled cups are the easiest way to identify red oak versus white oak.

Closeup of two red oak acorns with caps, 8 Oct 2024 (photo by Kate St. John)

It was hard to find two acorns that still had their cups. These two are intact because a worm drilled into the nuts. I searched through lots of cup-less acorns to find them.

Big mast year for red oaks in Schenley Park, 8 Oct 2024 (photo by Kate St. John)

For decades I’ve walked past these trees without thinking about their odd looking trunks. The trunks have hips because …

Grafted cherry trees, Schenley Park near Westinghouse Memorial, 8 October 2024 (photo by Kate St. John)

… these ornamental cherry trees were grafted onto healthy trunks of (probably) native trees. This is usually done because the non-native tree roots are likely to fail in North America.

Grafted cherry trunk, Schenley Park, 8 October 2024 (photo by Kate St. John)

Fall leaf color is not brilliant yet but burning bush berries are ready to entice birds. Euonymus alatus is a pretty plant but is officially a Noxious Weed in Pennsylvania since January 2023.

Euonymus fruit in garden bed, 2 Oct 2024 (photo by Kate St. John)

Northern Lights Last Night in Pittsburgh

Weather & Sky
Aurora borealis at North Park, Allegheny County PA, 10 Oct 2024, 10:15pm (photo by Steve Gosser)

11 October 2024

We usually don’t see the aurora borealis as far south as Pittsburgh but this year has been amazing. Last night was its third visit and perhaps the best.

Having missed the other two events I went to Schenley Park golf course last night from 8:30 to 9:00pm. Knowing it would only be visible in cellphone photos I took a lot of pictures. Obviously there is too much light pollution! You can count the stars on one hand in my photo. But the sky is pink.

Faint pink of the aurora borealis at Schenley Park, 10 Oct 2024, 8:45pm (photo by Kate St. John)

Steve Gosser went to Allegheny County’s North Park and waited a long time for the aurora to become intense. At 10:15pm he captured the red and green photo at top. Wow!

Dave Brooke went further afield to Armstrong County and waited past midnight. He captured this still photo and …

Aurora borealis, Armstrong County, PA, early hours of 11 Oct 2024 (photo by Dave Brooke)

… this timelapse video.

Aurora borealis, Armstrong County, 10-11 Oct 2024, embedded video by Dave Brooke on YouTube

Double wow!!

A good view of the northern lights comes down to location and patience … and a good camera.

p.s. Dave described his timelapse process in the video description, copied below:

October 11th 2024 saw a G4 Geomagnetic storm with a Kp:8. This timelapse was taken in Armstrong Co in Western PA starting around 9:30pm. It consists of 193, 10 second exposures with an interval of 5 seconds between each shot. They were taken with a Canon R5 and a Sigma 14-24mm Art lens at 14mm. The aperture was 2.8 and ISO 800. The sequence was rendered in LRTimelapse and outputted at 1/2 speed.

— Description of video by Dave Brooke

What is a Wolf Tree?

Trees
White pine “Wolf Tree” in Red Rocks Park, South Burlington, Vermont, 2006 (photo from Wikimedia)

10 October 2017

When Europeans arrived in Pennsylvania the first thing they did was clear the forest for farms. 150 years ago the focus changed from chopping for farmland to clear-cutting to sell the wood. Clear-cutting ended in the complete deforestation of Pennsylvania in 1900-1920. Other than small patches of old growth forest, such as the one at Cook Forest, the Pennsylvania woods you see today is just 100+ years old.

A few old trees remained in unlikely places. Farmers sometimes left one tree in a field as shade for the animals or left a tree standing at the boundary line.

A future wolf tree: Lone tree in a field provides shade for the cattle (photo from Wikimedia Commons)

When the farm was abandoned the forest grew back and surrounded the lone tree. At top an ancient white pine is surrounded by a younger Vermont forest. Lone trees in Pennsylvania tend to be oaks.

In the late 20th century foresters dubbed them “wolf trees” because they believed that these huge older trees were “exhausting forest resources and should be eradicated to make way for profitable wood.” Eventually perceptions changed and wolf trees are now appreciated.

In 2015 I took a picture of a wolf tree at Cedar Creek Park in Westmoreland County. Nine years ago it had already been dead a long time and pieces of it were falling.

An old dead "Wolf Tree" at Cedar Creek Park (photo by Kate St.John)
An old “Wolf Tree” at Cedar Creek Park, Sept 2015 (photo by Kate St.John)

In subsequent visits to Cedar Creek I didn’t pay attention to this tree. I wonder how much of it still stands. I’ll have to go and see. (p.s. UPDATE on 15 Oct 2024: Mark Bowers checked and the tree is still there!

Read more about the changing attitudes about wolf trees at Berkshire Natural Resources Council: Debunking Wolf Trees

Tick Season Returns — On Birds

Insects, Migration
Connecticut warbler banded at Hays Woods with engorged tick above eyering, 8 October 2024 (photo by Nick Liadis, Bird Lab)

9 October 2024

Yesterday while Bird Lab was at Hays Woods, Nick Liadis captured and banded a Connecticut warbler! I was not there to see this rare bird (alas) but Nick sent me a photo. Notice that the warbler has an engorged tick at top right of his eye-ring.

Tick season has returned with a vengeance after a low period during August and September’s drought. Because they cannot live without moisture ticks hang out in humid vegetation, but there was very little available during the drought. All that has changed with the recent rains and black-legged ticks are now active for their mating season which they conduct on the bodies of deer. I was reminded of this yesterday when I saw a deer in Schenley Park with three engorged ticks on its face. (Ewwww!)

Birds that forage on the ground are likely to encounter ticks so its no surprise that the Connecticut warbler and this song sparrow acquired them.

Song sparrow with engorged tick below its eye
(photo from Scott, & Clark, Kerry & Coble, & Ballantyne,. (2019). Detection and Transstadial Passage of Babesia Species and Borrelia burgdorferi Sensu Lato in Ticks Collected from Avian and Mammalian Hosts in Canada. Healthcare. 7. 155. 10.3390/healthcare7040155)

Birds, in fact, are an integral part of the tick’s life cycle. Notice the robin in the Summer section of the CDC diagram below.

Black-legged tick life cycle (diagram from CDC enhanced with lifeform names)

I used to say that deer were the black-legged ticks’ long distance transport system but I’ve changed my mind. It’s birds. A 2015 study found that 3.56% of the songbirds migrating north into Texas in the spring are carrying tick(s), most of which are native to Central and South America.

The bird-tick transport system works both ways. A 2019 tick-host-pathogen study in Canada found that some birds carry ticks with pathogens on fall migration.

Poor birds! They need all the strength they can get to complete their migration. It doesn’t help when ticks are sucking their blood.

Meanwhile, be careful about ticks out there! Lyme disease, transmitted by ticks, is terrible. Check your clothing while you’re in the field and thoroughly check your body for ticks when you return home. Click here for ways to prevent infection by keeping ticks off your clothes and body.

p.s. Support Nick Liadis’ efforts with a donation at Bird Lab’s GoFundMe site.

Visiting Birds Find New Insect Snacks

Bird Behavior, Migration
Immature yellow-bellied sapsucker near spotted lanternflies, Frick Park, 6 Oct 2024 (photo by Charity Kheshgi)

8 October 2024

Bird migration was intense over Pittsburgh on Friday night, 4 October, when more than 20,000 songbirds flew south overhead. We saw the results on Saturday morning in Frick Park where a new cohort of species had arrived with good news: Some of them were eating spotted lanternflies!

The new species included ruby-crowned kinglets, white-throated sparrows, yellow-bellied sapsuckers and yellow-rumped (myrtle) warblers. The mix was quite a change from September’s warblers.

Most of the new arrivals were feeding on tiny insects but the juvenile sapsucker, pictured above, was attracted to sweet lanternfly honeydew on ailanthus trees. He was too young to have ever seen a spotted lanternfly but he was curious. “Are these edible?”

Immature yellow-bellied sapsucker looking at spotted lanternflies, Frick Park, 6 Oct 2024 (photo by Charity Kheshgi)

Yes.

Perhaps the sapsucker got the idea from a northern cardinal that ate a lanternfly further down the trail. (I don’t have a photo of that incident; this one is from iNaturalist, New York.)

Northern cardinal eating spotted lanternfly, NYC (Creative Commons photo by
matthew_wills via iNaturalist)

Olive-sided flycatchers eat spotted lanternflies, too, though they don’t contribute much in Pittsburgh because they are rare here.

Olive-sided flycatcher (photo from Wikimedia Commons)

However, when an olive-sided flycatcher was passing through Howard County, Maryland in early September Mei Shyong photographed it eating a spotted lanternfly. The thumbnail below is just a hint. Click here or on the image to see her photo at Howard County Concervancy on Facebook.