Archive for the 'Crows, Ravens' Category

Oct 24 2014

Move Along, Move Along!

Published by under Crows, Ravens

Not everyone is as enthusiastic about winter crows as I am.  If you walk or park your car beneath the roosts you’re surely disgusted by the mess they make.  What to do? Move the crows.

Central New York state has lots of experience with crow wrangling.  At times Auburn has had 70,000 winter crows, more than two and a half times their human population of 28,000.  Years of trial and error have shown that killing crows doesn’t work but moving them does.

So now, every fall Central New York gets ready to move the crows to locations that aren’t so bothersome.  This August 2012 video shows a seminar in Baldwinsville, 20 miles northeast of Auburn … as the crow flies.

Move along, crows. Move along!

 

(YouTube from Central New York, WSTM)

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Oct 20 2014

Planning Their Next Move

Published by under Crows, Ravens

A small assembly of crows (photo by Tom Harpel via Wikimiedia Commons)

Last month the crows had a meeting up north.

What are we going to do when it gets cold?  We can’t stay here.

Yup. These fields have grasshoppers now but they’ll be bare as soon as the frost hits.

Vince told me there are some nice places south of here in the Ohio Valley.  He recommended Wheeling Island and Pittsburgh.

I hear Pittsburgh’s great, especially the East End. Everyone had a great time last year.  Stay away from the Cathedral of Learning, though.  Peregrines live there.

OK, so we’ll go to Pittsburgh.

When do we leave?

In October.

In the past few days Anne-Marie, Julie and Anne have seen flocks of crows at dusk in Shadyside and Oakland.

The crows are back in town. Woo hoo!

 

(photo by Tom Harpel via Wikimedia Commons. Click on the image to see the original)

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Sep 12 2014

How Quickly Can You Pass These Tests?

This is a test.  For the next 3+ minutes wild New Caledonian crows will solve six physics problems in water displacement.

What will raise the floating treat?  If there are two treats which method is fastest?  The challenges are:

  1. Sand versus Water:  Will the crow know that there’s no point in dropping stones onto sand?
  2. Light versus Heavy objects:  Do heavy objects work better than light ones?
  3. Solid versus Hollow objects: Do solid objects work better than hollow ones even though the hollow objects weigh the same?
  4. Narrow water column versus Wide:  Which column takes longer to elevate?
  5. High versus Low water:  Is it faster to get the treat when the water is already close to the top?
  6. U-tube with a hidden connection:  Very hard! Will the crow figure out that one of the wide tubes governs the water level in the narrow one?

In the video the crows solve every problem but behind the scenes they faltered on the U-tube test so the scientists say they flunked it.

How quickly can you solve these physics problems?  Be quick on the U-tube test or else …

This experiment was tried with New Caledonian crows, Eurasian jays, and human children.  Read all about it here in PLOS One.

My favorite quote from the Discussion is: “The results from the current U-tube experiment suggest that New Caledonian crows are comparable to Eurasian jays, but differ from human children.”   ;)

 

(video from PLOS Media on YouTube)

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Apr 25 2014

Smart Black Birds On Camera

Raven on nest at Wellesley College (screenshot from Wellesley College ravencam)

Tired of being outdone by celebrity bald eagles and peregrine falcons, ravens have decided to get into the act.

Last October a pair of common ravens chose Wellesley College as the smart place to be.  Over the winter they scoped out the campus and evaluated future nest sites.  By March it was evident they’d made a wise choice when they built their nest on a high fire escape at the Science Center.  Their platform is enclosed by glass on three sides so they have great views and less wind.

They also have electricity, an Internet connection and night lights — perfect for a webcam — so Pauline and Henry are now celebrities.

Named for the founders of Wellesley College, Pauline and Henry’s choice probably shocked the local raven population.  “What were you thinking!? Humans are unpredictably dangerous!  We never nest that close to them.”  But their unique choice has given them shelter while we get a window on their world.

Pauline laid two eggs in March, one hatched in early April, and now their nestling is growing every day.  Unlike peregrine falcon chicks, raven babies are not cute, fluffy and white.  Instead they’re born naked and awkward with a very large mouth.  When the parents come to the nest “the mouth” opens to show off its red interior.  In the weeks ahead the mouth will stay red but the body will transform into a feathered juvenile raven, one of the smartest birds on earth.

Smartly clothed in black, Pauline and Henry are happy to share their lives with you on camera.  Click here or on the screenshot above to watch them online.

 

(screenshot from the Wellesley College ravencam)

p.s. When ravens blink their nictitating membranes, their eyes look white.  Very cool!

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Jan 31 2014

Slow Motion Flight: Peregrine, Raven

Kick back for a moment with this Earth UnPlugged video from BBC Worldwide.

First published last August, it compares the flight styles of peregrines and ravens using slow motion high definition video.  You’ll see how the peregrine is built for speed and precision, the raven for aerobatics.

Another difference, something you can’t see, is in their attitude toward the flight exercise.  Both are trained birds but they have completely different reasons for participating — and it’s a difference between the two species.

The peregrine is all business.  He’s hunting and focused, no playing around.  He associates with his trainer for business reasons and has a radio tag in case he decides to leave.

The raven is out there for social reasons.  He’s spending time with his favorite “raven,” doing some cool maneuvers to capture airborne food, flying along with his mate.  (The raven considers his trainer to be his mate.)

The radio tag is also a subtle key to these individual birds’ personalities.  The young peregrine could hunt anywhere.  If he breaks training he’ll fly away.  The raven is so bonded to his “mate” that his trainer knows he’ll never leave.

Enjoy the video. Happy Friday!

 

(video by Earth UnPlugged, a BBC Worldwide channel on YouTube)

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Jan 17 2014

Black Tents

Common raven landing near a tent at a campsite in Death Valley, as seen from the back (photo from Wikimedia Commons)

We all know that wearing black is hot in the sun but did you know that it’s cooler than other colors when there’s a breeze?

According to page 154 of Ornithology by Frank B. Gill: “The cooling effects of wind are most pronounced on black feathers, which concentrate solar heat near the surface of the plumage.  Black feathers can increase the amount of heat that a bird’s body absorbs from the environment when there is no breeze. A light breeze, however, removes the accumulating surface heat and reduces further penetration of the radiant heat.”

“The black plumage of desert ravens increases convective heat loss, as do the robes and tents of Bedouin tribes in the Sahara.”

Whoa!  Black tents.  I had no idea people used black tents in the desert. (Obviously I’ve not been paying attention.)

Here’s a photo of a Bedouin tent in Jordan. Notice that the top is black!  The cloth is woven from the hair of their black goats.
Bedouin black tent in Jordan (photo by Anita Gould, Cretve Commons license, Flickr)

Use of black tents is not restricted to the Bedouin tribes in the Sahara and Middle East.  The color is popular in the middle of the arid lands that stretch from Africa to Asia as shown on this map from The Black Tent in Its Easternmost Distribution: The Case of the Tibetan Plateau by Angela Manderscheid.

Locations where black tents are traditionally used (linked from Case Western Reserve Univ,

Locations where black tents are traditionally used (from Case Western Reserve Univ, “The Black Tent in Its Easternmost Distribution: The Case of the Tibetan Plateau” by Angela Manderscheid)

 

People learned that black is cooler in the desert and adapted accordingly.

The raven knew it long before people found out.

Amazingly, a raven entered the scene as I was developing this article.  When I searched for a Bedouin “black tent” photo on Wikimedia Commons one result was this raven landing in a campground at Death Valley National Park.

His outspread plumage looks like a black tent.

 

(photo of a raven landing near a tent in Death Valley National Park via Wikimedia Commons. Photo of a Bedouin tent by Anita Gould, Creative Commons license via Flickr. Click on the images to see the originals. Today’s Tenth Page is inspired by page 154 of Ornithology by Frank B. Gill.)

excerpt link to Afghanistan: An Atlas of Indigenous Domestic Architecture by Albert Szabo, Thomas Jefferson Barfield.

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Jan 10 2014

Like A Small Monkey

Published by under Crows, Ravens

This excellent video from Grist explains why crows are doing just fine in our changing world.

“They have a very large brain for their body size, more on par with a small monkey than a typical bird, and that allows them to quickly make associations between what they saw and what it meant,” says crow expert John Marzluff.

Don’t miss Marzluff’s information on their food choices at the 0:58 mark in the video.

Yo, crows!

(video from GristTV on YouTube)

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Dec 10 2013

Crows Stay Warm

Published by under Crows, Ravens

 

The crows are still roosting near the University of Pittsburgh’s Chevron building, puzzling the crow watchers and annoying pedestrians.  In years past they always moved the roost to Polish Hill and the Strip District by the end of November.  But not this year.  We’re not sure why.

Maybe the lights are brighter or the location is warmer at Chevron.  Warmth is important!  It’s one reason why they roost together rather than alone.

All night long they perch on the branch tips of large bare trees and jostle to stay warm.  The colder the night, the closer they huddle.  Their social hierarchy determines who gets to be in the warmest central locations.  But they constantly readjust.  Peter Bell has heard them muttering and jostling when he leaves Chevron after dark.

For the next three nights low temperatures will be in the teens. Watch this PBS NATURE video and see how active the crows will be this week, changing places to stay warm.

 

(video commentary from PBS NATURE’s “A Murder of Crows)

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Dec 04 2013

In A Shrinking Bubble

Ethiopian bush crow (photo from Wikimedia Commons)

As things stand now this intelligent, resourceful, omnivorous bird may go extinct in the 21st century.  Why?  Because he lives in a shrinking bubble.

For a long time scientists could not figure out why the Ethiopian bush-crow (Zavattariornis stresemanni) lived in only one 6,000 square mile area of southern Ethiopia.   He’s really smart, eats anything, and nests cooperatively but the bush-crow does not expand his range even though the habitat bordering his domain appears to be exactly the same.

His size and threatened lifestyle resemble that of the Florida scrub-jay whose range was 7,000 square miles but an area of suitable habitat much smaller.  Scientists approached the bush-crow with the same tools they used on the scrub-jay and came up empty.  The bush-crow’s bordering habitat was the same.  Why didn’t the bush-crow use it?

Then in 2012 a team headed by Dr Paul Donald of the RSPB figured out that the Ethiopian bush-crow lives in a cool, dry climate bubble where the average temperature is less than 20oC (68oF).  Outside his range it’s hotter and he won’t go there.  Terrain and elevation created his zone but climate change is raising the temperature and the bush-crow’s bubble is shrinking.

If his problem was caused by loss of habitat, as it is for the Florida scrub-jay, laws and habitat restoration could increase the bush-crow’s available land but climate change is a much thornier problem requiring international political will.  This bird is endangered.

Right now there are about 9,000 breeding pairs of Ethiopian bush-crows on earth.  But for how long?

Click here to read about the Ethiopian bush-crow’s climate preference.  Click here for his range map.

 

(photo from Wikimedia Commons. Click on the image to see the original)

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Dec 03 2013

Humans With Feathers

Published by under Crows, Ravens

American crow (photo by John Beatty)

By now scientists are quite convinced that crows are smart but the physical layout of crows’ brains puzzled them for a long time.  Our seat of intelligence, the “smart” part of the human brain, is small in crows.  In fact it’s small in all birds.  So where does all this braininess come from?  A different part of the brain.

Tübingen neurobiologists Lena Veit and Professor Andreas Nieder proved this by having trained crows run memory tests on crow-accessible computers.  The crows tapped the touchscreen with their beaks to select the answers.

The test was this:  Here’s an image. Remember it.  Now here are two images: one matches what you just saw, the other does not.  In this battery of tests, pick the similar one.  In the next round, pick the different one.

The crows not only mastered these tests but according to Science Daily when Veit and Nieder “observed neuronal activity in the nidopallium caudolaterale, one group of nerve cells responded exclusively when the crows had to choose the same image while another group of cells always responded when they were operating on the “different image” rule. By observing this cell activity, the researchers were often able to predict which rule the crow was following even before it made its choice. … This high level of concentration and mental flexibility is an effort even for humans.”

Wow.

Crows make and use tools. They remember faces. They remember a large number of feeding sites.  They plan their social behavior around what others are doing.

“I thought we were going to the dump this morning,” says a crow to his buddy.  “We aren’t?  OK.  Whatever.  I’ll follow you.”

Humans with feathers.

Read more here in Science Daily.

 

(photo by John Beatty)

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