Category Archives: Crows & Ravens

Chasing Crows

Bird Behavior, Crows & Ravens
video by Claire Staples, Pittsburgh, 29 Dec 2018

31 December 2018

Unimpressed by the University of Pittsburgh’s scarecrow recordings, Pittsburgh’s winter crow flock continues to roost on campus. On Saturday evening, 29 December 2018, Claire Staples and I counted them for the Christmas Bird Count. It was harder than it sounds.

We began at 4pm at the highest vantage point we could find — the top deck of a parking garage between Trees Hall and the Petersen Events Center. From there we could see two huge streams of crows arriving from the south and east, pouring into the trees near Kennard Playground. Unfortunately the playground is over the edge of the hill so those crows went out of sight as soon as they landed.

By 5pm there were so many crows that new arrivals were landing on Trees Hall roof. We were pretty confident we’d counted 10,000 … and then they began to leave. What?!

The crows were headed for Schenley Heights so we followed in the car. We thought they might roost in the Heights but they were restless and on the move. Those in the air were headed for the Cathedral of Learning. We chased them down the hill.

Sure enough, Tennyson Avenue between Alumni and Clapp Halls was “Crow Central.” It was impossible to count them in the air as you can see in Claire’s video.

But I had another way to count them. Since 2016 I’ve tallied Crows-per-tree and Trees-with-crows to get an estimate of the Pitt roost. By car we tallied 45 trees with crows. With an average of 230 crows per tree that’s 10,350 crows at Pitt. Close enough. 10,000.

We think this is only half the crows in Pittsburgh. Claire and I saw just two of the four streams of crows that head to town at dusk from the north, south, east and west.

Where do the crows from the north and west spend the night? Are there 10,000 of them, too? We didn’t have time to chase them.

A clue concerning the origin of the Pitt crow roost

On Saturday Claire and I reminisced about the 2012 CBC when she and three other women counted 20,000 crows from a vantage point in the Strip District. That year a large part of the roost used trees at the closed housing project, Addison Terrace, that was downhill from Kennard Playground. In the spring of 2013 Addison Terrace was demolished and redeveloped into new homes. The first time Pitt had real trouble with crows was in the fall of 2013 when Addison Terrace was no longer available as a roost. Hmmmm!

(video by Claire Staples, 29 Dec 2018)

Crows, Do Not Enter!

Bird Behavior, Crows & Ravens
Jungle crow in Japan (photo from Wikimedia Commons)

In 2015 the International Coastal Research Center in Otsuhi, Japan figured out how to keep crows from pillaging their headquarters building.  With the advice of a crow expert they posted “Crows Do Not Enter” signs and the crows stayed away!  Here’s how it happened.

On 11 March 2011 the town where ICRC is located, Otsuchi, Japan, was devastated by nearly 30 foot waves from the Great East Japan Earthquake and tsunami. The photo below of the Kirikiri section shows how Otsuchi was wiped out.

Aerial view of tsunami damage in Kirikiri area of Otsuchi, Japan. 3 months later, 20 Jun 2011 (photo from Wikimedia Commons)

The International Coastal Research Center headquarters was severed damaged as well (the three-story building in the photo below).

Tsunami damage at Otsuchi, Japan, 4 days later 15 Mar 2011 (photo from U.S. Navy rescue operations via Wikimedia Commons)

The first two floors were wrecked, as seen in two photos from the ICRC website.  (Click here to see more photos of the damage.)

Tsunami damage to ICRC (images via ICRC Recovery website. Click this caption to see the originals in context)

However, by 2015 the local jungle crows (Corvus macrorhynchos) could not resist stealing the damaged materials inside the building.  During the nesting season they flew into the open building, ripped insulation off the pipes and carried it to their nests.  

To get rid of the crows the ICRC asked for help from Tsutomu Takeda, an environmental scientist and crow expert.  Rather than using scarecrow tactics he hung large signs on the pipes, visible from outdoors, that said “Crows Do Not Enter.”  

“Crows, Do Not Enter” signs at ICRC (photo from an ICRC article which is no longer online)

As soon as the signs went up the crows stayed away. This method was still working two years later when Mother Nature Network published the news.

Can the crows read the signs? No, but people can and when they do they look up to see if crows are in the building.  The crows hate it when people watch them stealing nesting material so they stopped doing it.

If the signs worked on jungle crows in Japan, perhaps they’ll work on American crows, too.  I wonder if our winter crow flock would stop roosting at the University of Pittsburgh if they put “Crows Do Not Enter” signs in the trees.  😉

(This post was inspired by MNN: Wild Crows seem to obey Do Not Enter signs, and a report from the ICRC which is no longer online.  Photos are from Wikimedia Commons, the ICRC Recovery Project website and the now-missing ICRC article. I encourage you to click on the captions to see the originals.)

Raven Gets Creative

Crows & Ravens, Vocalizations

Crows are common in the city but ravens are rare so I was surprised to hear a raven this week in Schenley Park.  It called and circled overhead waiting for its companion to arrive. “Brrrock! Brrrock!”  When the second raven caught up they flew away together.

I see ravens in town about twice a year but I only hear them make the Brrrock call.  If I lived where common ravens (Corvus corax) are common, I’d hear their wide variety of sounds.

This video from Anchorage, Alaska gives you an idea of the ravens’ vocal range.  He starts with Brrrock.   Then he gets creative.

(video by dougbrown47 on YouTube)

Odd Name With A History

Crows & Ravens
Red-billed chough in flight, Cornwall (image from Wikimedia Commons)

In the U.K. and Ireland there’s a bird like a crow with a red bill, red legs, and a very odd name. 

Red-billed choughs are found in Europe, Asia, and northern Africa but the smallest race, the Cornish chough (Pyrrhocorax pyrrhocorax pyrrhocorax), is endemic to the British Isles.

Red-billed choughs in Cornwall (photo by Andrew on Flickr, CC license)

Centuries ago red-billed choughs were common on the south coast of England where they were revered enough to appear in heraldry.  The City of Canterbury’s coat of arms (at left below) includes three choughs from Saint Thomas Becket’s coat of arms.  (Becket was the Archbishop of Canterbury who was murdered in the Cathedral in 1170 by followers of King Henry II.)
A second example comes from the less famous Peter of Bowhay whose arms contain a single chough (at right).

(left) City of Canterbury coat of arms (photo by Julian Walker via Flickr CC license)
(right) Arms of Petre/Peter of Bowhay, Dunchideock, Devon (via Wikimedia Commons)

The word “chough” looks odd because the gh sound has gone out of use. In most English dialects it’s now silent (light or neighbor) or pronounced “f” (enough or laugh).  Here’s what the <gh> used to sound like:

<gh> voiceless velar fricative (audio from Wikimedia Commons)

The name chough, now pronounced CHUF, originally mimicked the bird’s sound.  Can you hear the old resemblance in these chough calls?

Red-billed chough (audio by Harry Hussey on xeno canto XC408367)

In the 20th century Cornish choughs disappeared from England though they remained in Ireland, Wales, western Scotland and the Isle of Man.  In 2001 choughs returned to nest in Cornwall.

Nowadays you can see and hear them at Cornwall’s cliffs, calling “Chough!” as they fly.

Red-billed choughs take to the air, Cornwall (photo by Paul Gillard via Flickr, CC license)

(photo and audio credits are in the captions. Click on the captions to see the originals.)

(*) <gh> has a throaty sound in Scottish English.  Elsewhere chough is sometimes said “shuf.” 

Crows Causing Trouble?

Crows & Ravens
Crow warning sign in
Fukuzumi-cho, Eniwa, Hokkaido, Japan (photo from Wikimedia Commons)

Sometimes crows can’t help it. They cause trouble at home and abroad.

Crows At Home:

Last week Pittsburgh’s growing winter crow population — composed of American crows (Corvus brachyrhynchos) and a few fish crows (Corvus ossifragus) — caused trouble at the University of Pittsburgh.

Andrew Mumma reported that the population roosting on Pitt’s campus exploded Wednesday night, October 17, resulting in slippery, stinky sidewalks on Thursday morning.

Pitt responded Thursday evening by playing the “Crow Scare” tape near Clapp Hall. (Click here to hear it.)  When Karen Lang left work around 7pm she saw a peregrine falcon, maybe Terzo, dive bombing the crow zone at Alumni Hall.  Did the crows annoy him? Or was it the kakking noise on the tape?

Crows abroad:

The caption for the Wikimedia photo above says “A sign warning people about crows in Fukuzumi-cho, Eniwa, Hokkaido.” It’s probably referring to jungle crows (Corvus macrorhynchos), also called large-billed crows, a common bird in Japanese cities.

Large-billed crows are famous for causing problems in Japan.

So what is this sign about?  I can’t read Japanese but maybe you can. Here’s a closeup.

A sign warning people about crows in Fukuzumi-cho, Eniwa, Hokkaido

If you know what this says, please leave a comment with the answer.  I would love to know what the crows are up to!

UPDATE:  See the Comments below for two translations.

(two sizes of the same photo from Wikimedia Commons; click on the caption to see the original)

Get Ready for Crows

Crows & Ravens, Migration
Crows gathering at dusk, Alumni Hall, November 2013 (photo by Kate St. John)

I heard them coming last Friday when 50 crows flew over my neighborhood late in the afternoon.  I heard them again Monday morning before dawn, flying over my house in the dark.

Pittsburgh’s winter crow flock is building.  Right now the number is small but by Halloween we’ll see 1,000 of them at dusk near Pitt’s Alumni Hall. Even more of them in November.

Crows gathering on Alumni Hall, November 2013 (photo by Kate St. John)

By December expect 10,000 crows.  In March they’ll be gone.

Winter’s coming. Get ready for crows.

p.s. Here’s what they were like last year By the Light of the Supermoon.

(photos by Kate St. John, November 2013)

Crows At Work

Bird Behavior, Crows & Ravens
Carrion crow picking up (photo from Wikimedia Commons)

On Labor Day, let’s watch some crows at work.

At a theme park in France trained crows are showing humans not to litter.  At least that’s one of the ideas behind teaching crows to pick up cigarette butts at Puy du Fou.

The historical theme park in Les Epresses, France has falconers who conduct live bird shows featuring falcons, owls, vultures and crows.  One day one of the crows picked up litter instead of the prop he was cued for.  The crowd was impressed.

Management was impressed too so now they have six trained crows who pick up cigarette butts in exchange for a treat.

The crows love their job. Their trainer says they’d do it all day if you let them.  Click here or on the image below to watch the crows in action.

Screenshot from AFP video

Read more in this article from Popular Science.

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

Merlin Attack! Raven or Crow?

Bird Behavior, Birds of Prey, Crows & Ravens, Newfoundland, Travel

Merlin attacks a big black corvid at Renews, NL (photo by Trina Anderson)
Merlin attacks a raven at Renews, NL, 10 July 2018 (photo by Trina Anderson)

Last week in Newfoundland our birding tour witnessed an amazing bird interaction when a merlin attacked a big black corvid in the air.  It happened so fast that we had to think hard about the birds’ identities.

Yes the attacker was a merlin —  a small, streaky dark, very fast falcon that made this sound as it attacked. (Xeno-canto XC332445: alarm calls of merlin pair recorded by Pritam Baruah in Churchill, MB, August 2016)

But was the big black bird a crow or a raven?

Fellow traveler Trina Anderson captured the action with her camera. Before we saw her photos we could only identify the corvid by size and behavior.  We decided “raven” based on the relative size of the two birds and the behavior of the raven.

  • Merlins are 2/3 the size of a crow but less than half the size of a raven.  Overhead the merlin was tiny compared to the bird it attacked, so it had to be a raven. Trina’s photos show the size difference.
  • The black bird barely flapped during the interaction and it flipped upside down in flight (see the last photo). Crows flap hard when they’re under attack and they don’t fly upside down.
  • During the fight it was hard to see the diagnostic field mark — the tail — but Trina’s next photo shows the corvid has a wedge-shaped tail. That means “raven.”

Merlin attacks a corvid, Renews, NL, 10 July 2018 (photo by Trina Anderson)
Merlin attacks raven, Renews, NL, 10 July 2018 (photo by Trina Anderson)

Merlin attack! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)
Merlin attacks! Raven flips upside down, Renews, NL, 10 July 2010 (photo by Trina Anderson)

It’s hard to tell ravens from crows unless you have some practice.  Get tips on how to tell them apart in this 3 minute video from The Raven Diaries: Ravens vs Crows, they’re different!

 

(photos by Trina Anderson. See more of photos of our Newfoundland trip in her Flickr album.)