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)
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.)
The raven knew that black was cool long before people found out. His outspread wings look 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.
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.
Crows flying past Chevron Building at Univ of Pittsburgh (photo by Kate St. John)
10 December 2013
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.
As things stand now this intelligent, resourceful, omnivorous bird may go extinct in this century. Why? Because he lives in a shrinking bubble.
For a long time scientists could not figure out why Stresemann’s 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 areas 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 Stresemann’s 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. The bush-crow’s bubble is shrinking and he is Endangered.
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.
Right now there are about 9,000 breeding pairs of Stresemann’s bush-crows on earth. But for how long?
Click here to read about Stresemann’s bush-crow’s climate preference. Click here for his range map.
(photo from Wikimedia Commons. Click on the image to see the original)
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.”
Crow-scare recording at Univ of Pittsburgh, Nov 2013 (video by Jason Carson on YouTube)
15 November 2013
Since late October, Pittsburgh’s winter crow flock has been big and brash in Oakland. At dusk they flood the sky, gathering on roofs and treetops to choose a place to sleep. Last week they roosted in the trees around Pitt’s Student Union and the Cathedral of Learning. This got them into big trouble!
Every night pedestrians dodged the “rain” from trees filled with crows and every morning the sidewalks were a slippery crow-poop mess. The crows had to go. But how to convince them?
Last weekend Pitt positioned a loudspeaker on the low roof of the Student Union and played very loud bird distress calls over and over all night. They ran it for five nights, Friday through Tuesday, Nov 8-12.
Most people didn’t know it was a recording. In the dark it sounded like birds fighting and dying: a robin in awful distress, an unidentified bird screaming and a peregrine kakking.
Late Saturday night Jason Carson recorded the video above and tweeted me with the question: “What is this? Are the peregrines fighting?”
Initially I was fooled and thought it was real, though it didn’t make sense. Any bird suffering that much would have died after the first assault and the noise would not repeat. Then Pat Szczepanski told me she heard it Sunday night at 6pm and it dawned on me. Duh! It’s a recording.
Usually crows are not impressed by bird distress recordings. They are way too smart to be fooled for long. Sometimes the only thing that will move them are bird-scare firecrackers like the ones they use at Penn State (click here for videos of Penn State’s “crow wars”).
Why were a few nights of noise enough to move Pittsburgh’s crows away from the Cathedral of Learning? I have a theory and I think it’s pretty good.
Crows are afraid of peregrines but they’re more afraid of great horned owls. They know Dorothy and E2 live at the Cathedral of Learning and they know peregrines hate great horned owls so they probably figured “The enemy of my enemy is my friend” and they chose to roost at Pitt.
But last weekend there was an awful ruckus and the sound of peregrines defending their home. “Oh my gosh!” thought the crows, “The owl must be here! I hear the peregrines attacking it!”
In the dark Dorothy and E2 swooped low to investigate the noise. “Oh no!” said the crows, “The peregrines are here! Fly away!”
The crows didn’t move far but they moved far enough. By Monday evening they were avoiding the trees on campus and roosting instead on the roof of Soldiers and Sailors Hall. Just far enough to avoid the owl and the peregrines. Just far enough that Pitt is happy. Just far enough that the noise has ceased and Dorothy and E2 can get a good night’s sleep.
Without real live peregrines at Pitt, the crows would not have been fooled.
As of today I’ve been writing Outside My Window for six years. The crows are crowing, “Yow!”
Every year I provide statistics, but since this is a Saturday I’ll keep it brief so we can get back to our errands or play time. (In my case, errands.) Here we go:
Did you know you’re one of 574 visitors per day (this year’s average) who generate 21% of all traffic to WQED.org?
Some days are more popular than others. Sadly the most visited blog entry was the news of Silver Boy’s death on June 14. More than 3,000 people read about him that day, 79 commented here, and many more commented via Facebook and at the news websites.
Falcon or Hawk? from 2011 continues to win the top prize from Google search.
Since the first big flock returned ten days ago Pittsburgh’s winter crows have been gathering at dusk in Oakland.
During Wednesday evening rush hour I saw a flock of 100 wheel high over Flagstaff Hill, circle twice and split in two. Half the crows dropped into Junction Hollow. The other half flew past CMU. The flock was so high and quiet that I was the only one to notice…
…until they landed. In the trees they have a lot to say and keep saying it until dark when they silently leave for the roost.
Their roost location is still evolving. In October and early November they favor the trees near Soldiers and Sailors Hall but typically move to Polish Hill by Thanksgiving. I can tell where they spent the night by the marks on the sidewalk.
The crows have favorite trees they return to each evening. On Monday a lot of them returned to a surprise.
While they were away, eight of their roosting trees disappeared from Ruskin Avenue. Literally disappeared! Here’s what’s left of one of the London plane trees. Click on the photo to see the row of stumps.
A couple of Novembers ago I counted crows roosting in those very trees and estimated 40 crows per tree that night. Multiplied by eight my guess is that 320 crows had to find a new place to roost on Monday. This was significant. I wish I’d been there to see their reaction.
What did they do? They probably shook their heads (“Those humans were at it again!”) and moved on. After all they’re transient. They sorted it out. It was no big deal.
Crows adapt.
(photos of crows by Sharon Leadbitter. photos of trees and sidewalk by Kate St. John)
p.s. I predict that non-birders will first notice the crows this coming Monday evening. Some of you know why. 😉
Their numbers grew quietly this month, gathering at the edges especially near Wilkinsburg. Last night it was official. The crows are here.
Peter Bell and Anne Marie Bosnyak emailed reports from Oakland. My husband called from Squirrel Hill.
Anne Marie said, “Saw a murder of crows at the playground across the street from the Church Brew Works last night and a coworker saw them this morning in Schenley! Borrowed from Thin Lizzy (source: http://www.lyricsondemand.com/)
The crows are back in town! The crows are back in town!
Guess who just got back today?
Them wild-eyed crows that had been away
Haven’t changed, haven’t much to say
But man, I still think them cats are crazy.”
Silence isn’t their strong suit. The crows will have lots to say in the days ahead.
Let me know when you see them.
(photo from Wikimedia Commons. Click on the image to see the original)
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