Category Archives: Crows & Ravens

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)

Happy New Year!

Crows harrass a white-tailed kite (photo by stonebird via Flickr, Creative Commons license)
Crows chase a white-tailed kite (photo by stonebird via Flickr, Creative Commons license)

Wishing you many birds and spectacular bird moments in 2018.

Happy New Year!

Tomorrow I’ll tell you about my First Bird of 2018.   (Think about sharing yours.)

 

p.s. This photo of crows chasing a white-tailed kite was taken by “stonebird” in October 2017 at Ballona Wetlands, Los Angeles, California.  What a thrill!

(photo by stonebird via Flickr, Creative Commons license)

What Are Crows Saying? Soon We May Know

Crows swirl above the University of Washington, Bothell (photo courtesy Univ Washington, Bothell)
Crows swirl above the University of Washington, Bothell (photo courtesy Univ Washington, Bothell)

Is a flock of 15,000 crows a burden or an opportunity?  At the University of Washington, Bothell it’s an opportunity for a groundbreaking study on crow communication.

Every year from fall to spring, 15,000 crows gather on campus on the way to their roost in the North Creek Wetlands.  These gatherings are their noisiest time of day.

Crows on the practice field at dusk, Univ of Washington, Bothell (photo courtesy Univ Washington, Bothell)
Crows on the practice field at dusk, Univ of Washington, Bothell (photo courtesy Univ Washington, Bothell)

Crows are intelligent so chances are good that they’re saying something meaningful — but no one knows what it is.

Last year UW Bothell biologist Douglas Wacker and acoustics expert Shima Abadi decided to team up and find out.  Working with a group of students, they tested audio equipment and the crows’ reactions to it.  They also wrote software to find the most interesting parts of the crow conversations so researchers don’t have to wade through hours of recorded caws to find the best parts.

Setting up the equipment was not as simple as you’d think.  Crows are wary of changes in their surroundings so audio equipment was introduced carefully on the rooftop of Discovery Hall, a building where the crows congregate.  By the time this photo was taken, the crows were cool with four audio rigs on the roof.

Crows on the roof of Discovery Hall near acoustic equipment (photo courtesy Univ Washington, Bothell)
Crows on the roof of Discovery Hall with acoustic equipment (photo courtesy Univ Washington, Bothell)

This winter Wacker, Abadi and their team of students will learn more about crow communication and pair it with video to determine who’s saying what.

What are the crows saying?  Soon we may know.

 

Read more about the study and see a video of crows on the roof in this article from the University of Washington, Bothell: Rooftop Wiretap Aims to Learn What Crows Gossip About at Dusk.

 

(photos courtesy Crows’ Call at University of Washington, Bothnell)

By The Light Of The Supermoon

Moon rising, crows roosting, Heinz Chapel, 1 Dec 2017 (photo by Kate St.John)
Moon rising, crows roosting, Heinz Chapel, 1 Dec 2017 (photo by Kate St.John)

Tonight is the night of the Supermoon, a full moon at perigee that looks 14% bigger and 30% brighter than normal.

What will you see by moonlight on Pitt’s campus tonight, clustered at the treetops like large black leaves?

Thousands of crows.

Despite the weird scarecrow sounds played from the buildings, Pittsburgh’s winter crow flock continues to roost in the mature trees surrounding the Cathedral of Learning and Heinz Chapel.

On Friday I tried to count them by the light of the moon. They were clustered in 30 trees and on the roof of Carnegie Museum. The densest trees held 300 crows.

Crows roosting in the trees near Heinz Chapel, 1 Dec 2017 (photo by Kate St. John)
Crows roosting in the trees near Heinz Chapel, 1 Dec 2017 (photo by Kate St. John)

Could there really be 9,000 crows in the area of Forbes, Fifth, Bellefield and Bigelow Avenues?  Maybe I over counted.  Last year I estimated 230 crows per tree making this total 6,900 crows on December 1 at 6:15pm.

What is their fascination with the University of Pittsburgh?  It isn’t the buildings.  It isn’t the lawn.  It’s the well lit trees.

Crows prefer to roost where they can see danger coming.  The campus is well lit for our protection.  The crows like it, too.

Well lit trees near the Cathedral of Learning with American crows roosting on top, 1 Dec 2017 (photo by Kate St.John)
Well lit trees near the Cathedral of Learning, 1 Dec 2017 (photo by Kate St.John)

Alumni Hall is a good vantage point for watching crows and the moon rise next to Heinz Chapel.

Stop by this evening to see it all by the light of the supermoon.

 

(photos by Kate St.John)

Weird Sounds To Scare Crows

Cathedral of Learning at night, Dec 2007 (photo from Wikimedia Commons)
Cathedral of Learning at night, Dec 2007 (photo from Wikimedia Commons)

This week pedestrians near the Cathedral of Learning are hearing weird scary bird sounds after sunset.  Yale Cohen recorded them on Wednesday and asked, “What is this?”

The recording sounds like a bird in distress followed by rapid peregrine “kakking.”  It’s an audio scarecrow.

Pittsburgh’s winter crow flock has decided to roost in Oakland bringing at least 4,000 crows into the trees on campus.  Every morning the sidewalks are a gooey smelly mess.  Here’s what the Fifth Avenue sidewalk looked like on November 14 (photo by Claire Staples).

Evidence of the crow roost near St. Paul's Cathedral, Nov 14, 2017 (photo by Claire Staples)
Evidence of the crow roost near St. Paul’s Cathedral, Nov 14, 2017 (photo by Claire Staples)

In 2013 the recordings worked, The Crows Moved, but this time they haven’t gone so far. Michelle Kienholz texted me on Wednesday:

Pitt aggressive bird sounds screaming out at different locations in sequence. Crows settling elsewhere but still on campus.

I’ve found crow evidence below the London plane trees by Carnegie Library, the Pittsburgh Public Schools office and St. Nicholas Cathedral.  The crows have moved — but only across the street.

They’ve already figured out the scarecrow. It’s annoyingly loud but not scary.

 

p.s. Why does the flock like to roost at Pitt?  Look how well lit the area is at night (photo at top)!  Crows like to sleep in tall trees where the lights are on.

(credits: Cathedral of Learning at night from Wikimedia Commons; click on the image to see the original. Messy sidewalk by Claire Staples.  Audio recording by Yale Cohen)

The Crow Report

Crows gathering to roost in a tree near the Cathedral of Learning, Pittsburgh, Nov 2017 (photo by Kate St.John)
Crows gathering in a roosting tree near the Cathedral of Learning, Pittsburgh, Nov 2017 (photo by Kate St.John)

The black silhouettes in this tree near the Cathedral of Learning are not leaves. They’re crows.

Pittsburgh’s crow population has swelled since the weather turned cold last weekend.  On Monday I counted 4,000 flying into Oakland from the south, pausing on the roof of Carnegie Museum before heading to their final destination.

American crows gather on the roof of Carnegie Museum, Nov 2017 (photo by Kate St. John)
American crows gather on the roof of Carnegie Museum, Nov 2017 (photo by Kate St. John)

I couldn’t even see the crows arriving from east, west and north but distant trees at Schenley Farms were coated with crows and hundreds, perhaps thousands, gathered on the rooftops north of Fifth Avenue.  My cellphone barely captured a look at them as night was falling.

Crows fly at dusk, Fifth Avenue in Oakland neighborhood of Pittsburgh, Nov 2017 (photo by Kate St.John)
Crows fly at dusk, north of Fifth Avenue in Oakland neighborhood of Pittsburgh, Nov 2017 (photo by Kate St.John)

Where did they roost?  I didn’t stay long enough to find out, but they left their evidence behind.

On Tuesday Claire Staples sent me photos from St. Paul’s Cathedral on Fifth Avenue.  The crows left a mess on the wall and sidewalk below the stately London plane trees.

Evidence of the crow roost near St. Paul's Cathedral, Nov 14, 2017 (photo by Claire Staples)
Evidence of the crow roost near St. Paul’s Cathedral, Nov 14, 2017 (photo by Claire Staples)
Sidewalk evidence of the crow roost near St. Paul's Cathedral, Nov 14, 2017 (photo by Claire Staples)
Sidewalk evidence of the crow roost near St. Paul’s Cathedral, Nov 14, 2017 (photo by Claire Staples)

For now the crows are roosting near Fifth Ave and Craig Street but that will change.   They’re wearing out their welcome.

(photos by Kate St. John and Claire Staples)

They’re Back!

American crows (photo by CheepShot via Wikimedia Commons)
American crows (photo by CheepShot via Wikimedia Commons)

The crows are back in town!

Tuesday evening (October 23) Michelle Kienholz sent me the photo below of a huge flock of crows flying over Schenley Park toward CMU at 6pm.  See those specks above the horizon?  Hundreds of them!

Flock of crows flying toward CMU at dusk, 23 Oct 2017, 6:07pm (photo by Michelle Kienholz)
Flock of crows flying toward CMU at dusk, 23 Oct 2017, 6:07pm (photo by Michelle Kienholz)

Yes, it’s late October and the crows are back in Pittsburgh for the winter.  This is just the beginning of the flock.  More will follow.

In the next few weeks the crows will move their roost several times until they settle on a favorite safe place.  Meanwhile, you’ll see them at dawn and dusk flying down the Allegheny River valley and through Oakland.

Last year crows made the news by plaguing Pitt’s campus:  Annual crow stopover makes work for Facilities.

Will they roost at Pitt this year?  Stay tuned.

(photo credits: three crows by CheepShot on Wikimedia Commons; click on the image to see the original.  Crows darken the sky near CMU by Michelle Kienholz)

As The Crow Flies

On Wednesday we learned how flapping birds save energy.  Today we’ll watch them fly in slow motion.

In this video from India, house crows (Corvus splendens) use their slotted wings to stay aloft in the strong wind.  Someone off camera is tossing bread in the air.  The crows hover and flap to catch it.

Slotted wings save energy as the crow flies.

It looks like fun.

p.s. Test your skills at identifying birds in flight.  Find a pigeon (or three) that parachutes in to join the flock.  How can you tell it’s a pigeon? Pigeons have pointed wings.

(video by Sudhir, Suke on YouTube)

Flapping Saves Energy

Multiple wingtips vortices roll off the tips of a flying jackdaw's wings (photo credit: Aron Hejdström via Science Daily)
Multiple wingtips vortices roll off the tips of a flying jackdaw’s wings (photo linked from Phys.org, credit: Aron Hejdström)

It doesn’t make sense but if your wings are the right shape flapping saves energy.

Birds and airplanes must constantly overcome drag to stay aloft. One source of induced drag occurs during lift when swirls of air, called vortices, roll off the wingtips.  This small plane generates a huge wingtip vortex, forcing it to burn more fuel as it flies.

Wingtip vortex from an airplane (photo from NASA in the public domain on Wikimedia Commons)
Wingtip vortex from an airplane (photo from NASA in the public domain on Wikimedia Commons)

Large soaring birds, such as turkey vultures, reduce drag in two ways. Their wingtip feathers form slots that break the single vortex into smaller ones (small is good!), and they turn their wingtips up as they soar.

Turkey vulture (photo by Chuck Tague)
Turkey vulture (photo by Chuck Tague)

Southwest Airlines turns up its wingtips, too, to save fuel.

Wingtip on a jet, tip turned up to reduce wingtip vortex (photo from Wikimedia Commons)
Wingtip turned up to reduce wingtip vortex (photo from Wikimedia Commons)

But what about smaller birds that flap all the time?  Are they doomed to inefficient, labor-intensive flight?  A new study from Sweden says no.

Biologists at Lund University studied jackdaws (Corvus monedula), a corvid smaller than the American crow. Using mist and multiple cameras they found that the birds’ slotted feathers, specifically designed for flapping flight, also break up the vortex into multiple swirls.  See them rolling off the wings in the study photo at top.

Now that we know slots are efficient for both flapping and soaring, what prompted their development? The study’s authors “propose the hypothesis that slotted wings evolved initially to improve performance in powered (i.e. flapping) flight.”

In fact, flapping saves so much energy that author Anders Hedenström suggests, “We could potentially build more efficient drones to fly with active wingbeats. Within a ten-year period, we could see drones which have the morphology of a jackdaw.”

Read more about the study at Science Daily or the original paper here at The Royal Society.

(photo by Aron Hejdström linked from Phys.org)