25 December 2023
Merry Christmas to all, and to all a good night!
Merry Christmas
Holiday Magic at Phipps
24 December 2023
In the run-up to Christmas I was too busy to fit in a trip to Phipps Conservatory’s Holiday Magic but others have done so and provided videos.
See the show in Scott Hirschman’s 12-minute video, created with a wearable panoramic camera.
There’s still time to visit in the next 2+ weeks. The show is open through 7 January 2024.
Order your tickets in advance –> Phipps Conservatory Tickets
Eats Fruit and Leaves
23 December 2023
Early this week a big flock of American robins came to my neighborhood, ate all the fruit they could find, and left.
On Monday morning, 18 December, they were frantically eating this pyracantha fruit outside my window. At one point I counted 45 but they were moving so fast I think there were more.
The birds were frantic because they knew bad weather was coming. In mid afternoon it snowed.
The next morning the fruit was gone and so were the robins.
American robins are still in Pittsburgh but they’re feasting in other locations. When the fruit is gone and the ground is frozen, the robins will leave.
p.s. Today’s title reminds me of the 2006 bestselling book on punctuation by Lynne Truss called Eats, Shoots and Leaves. The comma in her book title is really important. Did the panda eat, shoot a gun, and then leave? Or did the panda eat two things — shoots and leaves? … In the case of today’s blog title: Robins don’t eat leaves. They eat fruit and leave the neighborhood.
It’s the Best Time of Year for the Northern Lights
22 December 2023
The short days of winter give us longer nights at the best time of year for viewing the northern lights.
Pittsburgh is generally too far south and always has too much light pollution from city lights for viewing the aurora borealis so let’s enjoy beautiful scenes from the arctic.
Wondering what areas are due to see the northern lights tonight or tomorrow? See NOAA’s 2-day aurora forecast maps or the 30-minute forecast for predictions of beauty in the sky.
Solstice Begins the Shortest Season
21 December 2023
When the sun stands still tonight at 10:27pm Eastern Time we’ll experience the shortest day of the year and begin the shortest season as well.
Regardless of the weather we change seasons four times a year based on astronomical events: December solstice, March equinox, June solstice, September equinox. Since these events occur at the same moment everywhere on Earth, each of the four seasons lasts the same amount of time for everyone. This is easiest to see on the Seasons page at timeanddate.com. A screenshot of Pittsburgh at 6am today is shown below.
If you don’t like winter, the Northern Hemisphere has the best arrangement. Our astronomical seasons from shortest to longest are:
- Winter = 88 days, 23 hrs, 39 mins (shortest)
- Autumn = 89 days, 20 hrs, 37 mins
- Spring = 92 days, 17 hrs, 44 mins
- Summer = 93 days, 15 hrs, 52 mins (longest)
Climate change guarantees that winter is the shortest weather season, too. Winter was 21% of the year in 1952 but will take up only 9% of the year by the end of this century.
Average seasonal lengths in Northern Hemisphere, information from Phys.org
So I’m not counting on a white Christmas.
Read more about the weather-based lengths of the seasons at:
American Chestnuts Too Rare to Roast
20 December 2023
The Nutty Series: American chestnut
‘Chestnuts roasting on an open fire / Jack Frost nipping at your nose / Yuletide carols being sung by a choir / And folks dressed up like Eskimos.’
— NPR: The Story Behind the Christmas Song
Despite the popularity of The Christmas Song, you’ll never find nuts of the American chestnut in the wild. By the time The Christmas Song was written in 1945 mature American chestnuts were nearly gone from North America. Today there are so few surviving mature trees that Wikipedia lists only 25 locations though people are always searching.
American chestnuts (Castanea dentata) used to be more abundant than oaks within their native range.
Then in the late 1800s someone imported Japanese chestnut trees that had chestnut blight. Asian chestnuts are immune, American trees are not. First noticed at the Bronx Zoo in 1904, chestnut blight spread quickly and nothing could stop it. By 1950 mature American chestnut trees were gone throughout their range.
Chestnut blight is caused by a fungus that kills the above-ground portion of the tree by getting under the bark and girdling the trunk.
The stump lives and sends up seedlings though they die as saplings. The process repeats — seedlings, sapling, death. Most stumps are at least a hundred years old.
To find a chestnut in the woods I look for the leaves at knee height. The photo below shows a typical American chestnut stump with seedlings. This one has a dead sapling as well.
For over 70 years arborists have been searching for a cure for chestnut blight and trying to breed immune American chestnuts. They have crossed the American chestnut with Chinese chestnuts, then back-crossed the hybrid to another American chestnut. These efforts, supported by The American Chestnut Foundation among many others, take decades to realize any success.
There are several experimental orchards in Pennsylvania. All are protected from deer.
Arborists collect the nuts, not to roast but to plant, so we’ll have more chestnuts some day.
As potentially successful hybrids become available, they are planted more widely — still in protected areas — to test their immunity and build back the chestnut population.
At these locations the leaves are above knee height.
Perhaps in one to two hundred years the nuts of American chestnuts will be easy to find and we’ll appreciate the first phrase of The Christmas Song again.
(credits are in the captions)
Using Salt to Get Water
19 December 2023
You’ve probably noticed that in humid weather table salt clumps in the salt shaker and sticks to the top. That’s because at the molecular level salt’s ions have a net positive charge that attracts atmospheric water which has a net negative charge. Salt literally pulls water out of the air and builds crystals. This process can make the top of the salt shaker moist or dampen a salted road on a humid day.
Can salt’s natural means of pulling water from the air be used to gather water in a larger way? Researchers led by Marieh B. Al- Handawi investigated Athel tamarisk (Tamarix aphylla), a desert plant native to Africa and Asia that takes up saline water with its roots and secretes excess salt through its leaves.
The tiny leaves are arranged alternately, almost wrapping the branches. The salt crystalizes on the leaves. Look closely and you can see tiny crystals.
The smaller crystals stay on the plant and attract more water, especially overnight as shown on this branch in the early morning (8 a.m.) with condensed water droplets.
As the sun gets higher it evaporates the water, leaving behind larger salt crystals which fall to the ground.
Every day the water cycle repeats: (A) branches attract water overnight, (B) water evaporates during the hot day while salt crystals grow, (C) water is gone and crystals are large, (D) during overnight high humidity the crystals attract water from the air and the plant absorbs the water. — paraphrased from PNAS: Harvesting of aerial humidity with natural hygroscopic salt excretions.
The tree is “drinking” from its leaves.
Researchers observed that at least one type of salt, lithium sulfate, forms small crystals that remain on the leaves and absorb water from the air. When the team added colored water to salty leaves, they watched the liquid stick to the crystal crust, then absorb into the plant’s leaves—evidence that the salty coating acts as a bona fide water collection mechanism.
— Science Magazine: Desert trees may pull water from thin, dry air using salt-encrusted leaves
The tree is very salt tolerant so this water collection process won’t translate directly for humans. But perhaps we’ll find a way.
For more information see Science Magazine: Desert trees may pull water from thin, dry air using salt-encrusted leaves or the PNAS publication Harvesting of aerial humidity with natural hygroscopic salt excretions.
(photos are from the Open Access PNAS article: Harvesting of aerial humidity with natural hygroscopic salt excretions)
Time’s Running Out: Where Are The Crows?
18 December 2023
For the past several years Claire Staples and I have counted crows for the Pittsburgh Christmas Bird Count (CBC). In a good year we count 20,000. In a bad year, 220. Stunning, isn’t it. The difference is not in the actual number of crows. It’s whether we can find them.
Please help. Let me know where you see crows overnight or after sunset, especially next week (after Christmas)!
You would think that 20,000 crows would be hard to miss but in late December they get tricky. Just before the CBC the crows change their roost several times or they split the roost and, suddenly, we can’t find half of them.
Several of you responded to Why Do 1000’s of Crows Roost in Town? with dates and locations. Your reports helped me figure out the crows moved on 11 December.
- Dec 10: Up until Dec 11 Tom saw them roosting near the VA Hospital in Oakland.
- Dec 11: Jeff Cieslak saw 1000s flying over the North Side parallel to Allegheny River, heading upstream.
- Dec 12: I counted 4,000 flying west-southwest over Schenley Park’s golf course at dusk. Where were they going?
- Dec 13: Sue Faust reported them hanging out on the North Side and flying over the Strip District at dusk.
- Dec 16: Carol Steytler counted as many as 10,000 roosting upstream of the 16th Street Bridge across from Heinz Lofts (across the river?).
Carol’s 16 December sighting matches a roost they used back in February 2021 (photo above) but they didn’t stay there long and I fear they won’t stay now. And this is only half of them.
Where will the crows be 12 days from now?
I know I’m going to miss their next move because I’ll be out of town December 21-28. Your help is really crucial. Please let me know where you see crows overnight or after sunset. Let me know where you see a big flock swirling. Claire & I also need to find a good vantage point for counting them.
Fingers crossed that we’ll successfully count the crows on Saturday 30 December.
Goshawks With Orange Eyes
17 December 2023
In case you missed it, the “northern goshawk” disappeared last summer. After only 66 years as a single species, the American Ornithological Union (AOU) split the northern goshawk back into its former status as two: the Eurasian goshawk (Accipiter gentilis) and the American goshawk (Accipiter atricapillus).
They basically look alike. The split was based on DNA and vocal evidence but you won’t note these things in the field and you won’t need to. The ranges do not overlap. This is the classic case of “Where did you see the bird?” In North America? Then “American.” In Eurasia? Then “Eurasian.”
Because I had seen a goshawk in Helsinki, Finland on 6 July 2017, I gained an additional Life Bird by the split. (See my lousy photos taken through binoculars below.)
At the time I marveled that this bird had orange-ish eyes. North American juveniles have yellow eyes (see illustration above) while adults have red eyes. Did the orange eyes mean this Helsinki bird was immature? A Finnish bird guide told me “No. In Finland the adults have orange-colored eyes, not red.”
The eye color difference is noted in Wikipedia and Birds of the World as well.
Eurasian goshawk:
In Europe and Asia, juveniles have pale-yellow eyes [until 3 or 4 years of age] while adults typically develop orange-colored eyes, though some may have only brighter yellow or occasionally ochre or brownish eye color.
— Wikipedia: Eurasian goshawk
American goshawk:
Typical adult American goshawk (A. atricapillus) shows strong supercilium, red eyes, black head, and blue-gray back.
— Wikipedia: American goshawk
Since their eye color changes slowly, perhaps more slowly than their plumage, it may be unreliable to use the color as a diagnostic difference between the two species. However, as a North American birder familiar with goshawks, those orange eyes in Finland made a difference for me.
Merlin at Schenley Park
16 December 2023
Nearly every winter since the late 1990’s when Bill Hintze(*) first reported them, you can usually find a merlin or two at Schenley Park golf course at dusk. Charity Kheshgi and I went looking on 12 December and right on time a large merlin, probably female, arrived 20 minutes before sunset.
The temperature was relatively warm but it was very windy and felt quite cold. The merlin didn’t care. As the sun set she flew to the top of a pine tree across the road. (She’s in this photo as a dot.)
Charity photographed her as a silhouette.
Interestingly she didn’t roost at the golf course. When it got darker she flew away to the south-southeast.
If you’d like to see a merlin, stop by the golf course about 40 minutes before sunset and walk around looking at the treetops. Parking is available at the First Tee parking lot.
(*) Bill Hintze and the merlins: I think Bill was the one who first found the merlins but I might be misremembering. If I’m wrong please leave a comment so I can correct the text.