Turning and Turning In The Widening Gyre

Central Arctic ocean currents (map by Brn-Bld via Wikimedia Commons)
Central Arctic ocean currents (map by Brn-Bld via Wikimedia Commons)

"The Beaufort Gyre is acting strangely," said the news at Yale Environment 360.  "Scientists say it could kick off a period of lower temperatures in Northern Europe."

Here's why.

The Beaufort Gyre is a wind-driven current in the Arctic Ocean. Traveling clockwise it keeps sea ice contained and moving so slowly that the ice thickens.

Every five to seven years the winds change direction and the gyre spins counter-clockwise, dumping icebergs and cold freshwater into the North Atlantic near Iceland.  Then the winds switch back.

But now the winds haven't changed direction for a long time, arctic ice is melting, and freshwater from the continents is flooding the Beaufort Sea.  The surface now holds as much freshwater as the Great Lakes and the gyre is spinning faster, still clockwise.

What will happen next?  The past gives us a hint.

Thirty years ago, when the gyre reversed direction for an extra long time, its ice and cold freshwater caused the North Atlantic herring fisheries to collapse and plunged Northern Europe into a temporary deep freeze.

Will the Beaufort Gyre change direction soon? And how long it will spin counter-clockwise?  No one knows.  Will the change be benign? Probably not.

The globe is warming overall (hence it was called "Global Warming") but the resulting climate change is both hot and cold, weird and unpredictable.

It's a bit like watching chaos unfold.

Turning and turning in the widening gyre
The falcon cannot hear the falconer;
Things fall apart; the centre cannot hold;
Mere anarchy is loosed upon the world ...
-- The Second Coming by W. B.Yeats

Read more about the Beaufort Gyre at Yale Environment 360.

(map of Arctic Ocean circulation by Zeimusu via Wikimedia Commons; click on the image to see the original)

Screech-Owls East and West

Eastern screech-owl in Pennsylvania, Dec 2017 (photo by Anthony Bruno)
Eastern screech-owl in Pennsylvania, Dec 2017 (photo by Tony Bruno)

No matter where they roost, screech-owls work to blend into their surroundings.

Above, Tony Bruno found an eastern screech-owl (Megascops asio) in a sycamore in Pennsylvania.  Below, Donna Memon has a western screech-owl (Megascops kennicottii) in a saguaro cactus in her Arizona backyard.

Western screech-owl roosting in saguaro (photo by Donna Memon)
Western screech-owl roosting in saguaro (photo by Donna Memon)

These two species look very similar so how do you tell them apart?

By range:  Eastern screech-owls live east of the Rockies, westerns live in the Rockies and West but their ranges overlap a little, especially in Texas.  The best way to identify them is by voice.

By voice:  Eastern screech-owls make monotonic trills and whinny sounds: (Eastern Screech Owl at Xeno-canto #286959 by Tim Spahr)

Western screech-owls are known for their double bouncing-ball trill:  (Western Screech Owl at Xeno-canto #383075 by Lance A. M. Benner)

 

Listen at dusk and you might hear a pair serenading in late winter.

 

(photo credits: Eastern screech-owl by Tony Bruno, Western screech-owl by Donna Memon)

Peregrines on Ice

Peregrine (black/green 48/BR) at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)
Peregrine (black/green 48/BR) at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)

Midday on Friday January 12, when it was unseasonably warm, Dave Brooke went down to the Tarentum Bridge and found a lot of ice flowing by on the Allegheny River.  He also found a pair of peregrines standing on it.

Peregrines standing on ice floes in the Allegheny River, 12 Jan 2018 (photo by Dave Brooke)
Pair of peregrines standing on ice floes in the Allegheny River, 12 Jan 2018 (photo by Dave Brooke)

Soon, one of them took off and flew near him on its way up the river.

Pair of peregrines on ice floes in the Allegheny River, 12 Jan 2018 (photo by Dave Brooke)
Pair of peregrines on ice floes in the Allegheny River, 12 Jan 2018 (photo by Dave Brooke)

Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)
Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)

Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)
Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)

Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)
Peregrine at Tarentum Bridge, 12 Jan 2018 (photo by Dave Brooke)

At the bird's closest approach it revealed its bands -- black/green 48/BR. They indicate he/she hatched at the Westinghouse Bridge in 2014, offspring of Hecla (Ironton-Russelton Bridge, 2009) and an unidentified male.  Click here for Banding Day photos.  48/BR is the one in the back.

Congratulations to Dave Brooke for capturing beautiful photos of these peregrines and for identifying one of them at the Tarentum Bridge!

UPDATE ON 15 JANUARY 2018!  News from Art McMorris indicates that band 48/BR is typically a female band but the sex of the bird was hard to determine at the time so Art used a female band just in case.  48/BR might be male.  We'll just have to wait and see.

 

(photos by Dave Brooke)

p.s.  In case you're wondering if Hope, the female peregrine at Pitt, will visit her old haunts in Tarentum, she's probably too busy.   While Dave was photographing the new pair at the bridge, Hope and Terzo were courting at the Cathedral of Learning.

Hope and Terzo court at the Cathedral of Learning, 12 Jan 2018 (photo from the National Aviary falconcam at Univ of Pittsburgh)
Hope and Terzo court at the Cathedral of Learning, 12 Jan 2018 (photo from the National Aviary falconcam at Univ of Pittsburgh)

Back Into the Deep Freeze

Bald eagle with ice on his forehead and belly, Crooked Creek, Jan 2018 (photo by Steve Gosser)
Bald eagle with ice on his forehead and belly, Crooked Creek, Jan 2018 (photo by Steve Gosser)

After a balmy Thursday and Friday the temperature is plummeting tonight to 5oF.

During the last deep freeze, Steve Gosser photographed a bald eagle at Crooked Creek with iced feathers on his belly and head. Notice how his head feathers are standing up as if he used hair gel!

The eagle's ice shows the great insulation power of feathers and how extreme cold can form ice very quickly when the eagle lifts his head out of the water.

He'll be getting another chance to wear icicles this weekend.  Brrrrr!

 

(photo by Steve Gosser)

Rare Falcon of the Desert

Ornithologists used to think this slate gray falcon was comfortably abundant but no one had thoroughly counted them.  Now that they have, the bird's been listed as Near Threatened.

Slightly smaller than a peregrine, the sooty falcon (Falco concolor) nests from Libya to Pakistan and spends the winter at Madagascar and the east African coast.  Like a peregrine it eats birds it captures on the wing. Like a kestrel it also eats dragonflies and large flying insects.

Scientists didn't know much about sooty falcons because they nest in deserts where it's extremely hot and inhospitable to humans.  Their nesting colonies are located where daytime temperatures reach 122oF !     (50oC)

With renewed interest in this Near Threatened falcon, scientists used remote cameras to video them on a desert island in Oman.  Notice how much the birds pant in the heat.

Soon we'll know more about this rare falcon of the desert.

 

For additional information read Sooty Falcons in Oman: Reproduction and population dynamics of a poorly studied, Near Threatened, colony-nesting raptor.

(video trailer for The Migrant - The Sooty Falcon in Oman on Vimeo)

The Back Toes

Snow Bunting in winter plumage (photo from Wikimedia Commons)
Snow Bunting in winter plumage (photo from Wikimedia Commons)

Birds' feet vary a lot from species to species.  Hawks have talons, ducks have webbed feet, and marsh walkers have very long toes (like this jacana).

Even their rear toes differ based on their life styles.

On Throw Back Thursday, learn about the back toes at:  Anatomy: Musing on Rear Toes.

 

(photo from Wikimedia Commons; click on the image to see the original)

Quiz: Identify Them in Flight

Waterbirds in flight, Florida 2013 (photo by Don Weiss)
Waterbirds in flight, Florida 2013 (photo by Don Weiss)

Can you identify these birds in flight?

Hints:

  • Don Weiss took the photo at Merritt Island, Florida.
  • I see 6 species.   Do you see more?
  • The pink ones are my favorite.
  • I see wood storks.  (But I'm wrong!  They are white pelicans.)

 

(photo by Don Weiss)

The Answer ... or at least part of the answer ...

Annotated birds in flight (photo by Don Weiss)
Annotated birds in flight (photo by Don Weiss)

  1. Glossy ibis
  2. White pelican --> white tail & black doesn't extend all the way to the body
  3. Common tern?  (Certainly a tern)
  4. Snowy egret (kc saw yellow feet)
  5. Great egret
  6. Roseate spoonbill
  7. White ibis

Any others?

Pitt Peregrine Highlights, 2017

Let's take a look back at last year's peregrine season with a slideshow of Pitt nesting highlights.  (Click on any photo to open the slideshow in its own lightbox.)

2017 was a lot calmer at the Cathedral of Learning nest than the year before.  Fortunately there was only one dramatic incident: Hope's abnormal behavior on April 25.  Here's a summary:

The 2018 nesting season will be here soon.  Stay tuned at the National Aviary falconcam at the University of Pittsburgh.

 

(slideshow photos from the National Aviary falconcam at University of Pittsburgh and by Peter Bell, John English and Kate St. John)

Why Is It Warming So Fast?

  • Friday, 5 Jan 2018

Egads, it was cold last weekend!  Here in Pittsburgh it was -6 to 11 degrees F, but yesterday things turned around.  Sunday (7 Jan.) started at -6oF but warmed to a high of 30.  Today will be above freezing and by Thursday the high will be 64oF.  That's a swing of 70 degrees in only four days!

The slideshow above shows this in color for January 5, 8, 11 and 12.

I'm not complaining that we're out of the deep freeze but ... this weather is really odd.  Why did it get so cold and why is it warming so fast?  Why don't we have a moderate winter like we used to?

Crazy as it sounds, it's because the arctic is warming faster than the rest of us.  When there's not a big temperature difference between the North Pole and the mid-latitudes (us) the jetstream slows down.  When it's sluggish, it wobbles in high amplitude loops that dip as far south as Florida(*).

The video below explains why.  I recommend watching it twice; you see more the second time.  (My end notes have info on millibars, etc.)

So when a cold loop settles over us, we're really cold and when it moves on we're really hot.  It happens quickly in both directions.

Don't put away your winter clothes on Thursday.  The forecast says it'll be 5 degrees on Saturday night.

 

(temperature forecast maps from NOAA; Jet stream explanation by Jennifer Francis on YouTube)

Definitions and notes:

  • A millibar (or mb) is a unit of air pressure.
  • The average air pressure at sea level is 1013.25 millibars = 14.7 pounds.
  • What's the significance of 500 millibars?   The 500 millibar pressure zone is where air pressure is half what it was at sea level, halfway up in the atmosphere. Since air pressure varies as weather systems move above us, the 500mb map is a great diagram of what the weather systems are doing.    Here's the air pressure map for Friday 5 Jan 2018 at 1200z (8am).  Notice that the pressure lines echo Friday's temperature map above.
  • (*) I wrote above that the jetstream dips as far south as Florida.  Well, it dips even further than that.  In June 2016 the northern jetstream crossed the equator and joined the southern one!

Smart and Cocky

Crow pulls the tail of an immature bald eagle, Delta, BC, Canada (photo from Wikimedia Commons)
Crow pulls the tail of an immature bald eagle, Delta, BC, Canada (photo from Wikimedia Commons)

Bald eagles are big and majestic, even the young ones like the immature bird pictured here.

Who's smart and cocky?   That small black bird in the back:  a crow pulling the bald eagle's tail.

Sometimes crows are a little too daring but this one is getting away with it.

 

(photo from Wikimedia Commons taken at Delta, BC, Canada. Click on the image to see the original)