I’ve seen a lot of ravens in the past two weeks — 11 in Minnesota, two as we landed at Pittsburgh airport, and one over Aspinwall on Tuesday. When I found Vance Crofoot’s 3-minute video explaining raven territories I was fascinated.
Immature ravens spend 3 to 4 years in large flocks of young ravens. On reaching adulthood, ravens pick a mate and go off to claim a territory.
Adult pairs display their territorial boundary by flying along the border.
Ravens know their neighbors and will sometimes fly with them along the mutual border.
Ravens help their neighbors drive out predatory threats.
Other ravens are not allowed to land in an adult pair’s territory. If they do they are challenged.
When a pair has chicks they aggressively drive out predators.
Once the chicks can fly, neighboring families meet up for “play dates” with their kids.
Youngsters also can bring friends home to play with.
Juvenile ravens stay with their parents for about 7 months. At the end of that time their parents aggressively drive them out of the territory.
The first comment on the video points out how different ravens are from crows!
Very informative! It’s interesting that the intergenerational behaviour is different from crows whose juveniles hang around longer and actively assist their parents in raising the next chicks and fledglings. The ravens’ cooperative behaviours are very well adapted to their needs and types of threats.
Yesterday’s news was sobering for Pittsburgh’s winter crow flock when the Post-Gazette reported that 50 crows found dead in January tested positive for H5N1 highly pathogenic avian influenza. It was the first incidence of avian flu in Allegheny County in more than two years.
The Pittsburgh crows were collected on Jan. 24 and tested positive in preliminary tests for the deadly virus on Feb. 10, said Travis Lau, communications director for the Game Commission.
It’s not hard to imagine how it happened. In January Pittsburgh’s winter flock of 15,000 crows roosts communally and fans out during the day as much as 50 miles to find food. The furthest travelers would have caught bird flu in an infected surrounding county and brought it to the roost. H5N1 is so contagious that it quickly spread to flock mates.
Crows moving in to roost near the Carnegie Science Center, 18 January 2025 (photo by Carol Steytler)
Apparently the crows knew what to do when death visited the roost. Crow watchers noticed that they changed the roost location a lot in January, perhaps avoiding sick birds and death locations. Maybe that’s why we haven’t heard of more crows deaths. Or maybe it simply takes weeks for the reports to reach us.
Crows in semi darkness (photo from Wikimedia Commons)
Meanwhile keep in mind that if you find a sick or dead bird you should not touch it!
Because of the highly contagious nature of the virus among birds, and the fact that, while rare, it can be transmitted to humans, the Allegheny County Health Department (ACHD), the Game Commission and other agencies urge the public not to touch sick or dead birds and report them to the Game Commission.
Anyone who sees a sick or dead wild bird should report it to the PA Game Commission at 833-742-9453.
Residents who suspect their poultry is infected with avian influenza should call the Pennsylvania Bureau of Animal Health and Diagnostic Services at 717-772-2852, option 1.
Residents who feel ill after contact with sick or dead birds should consult their primary care physician or the Pennsylvania Department of Health at 877-724-3258.
See the 2021-2025 distribution of highly pathogenic (HPAI, H5N1) avian influenza in wild birds in the U.S. by county as of mid-February 2025 here at USDA.
Ravens have moral standards, they understand fair play, and when someone breaks their trust they refuse to deal with them again. Ravens hate a cheater.
We know this because researchers conducted a trading experiment in 2017 in which they built trust with ravens (Corvus corax). When a raven offered bread, the human gave him his favorite food, cheese.
Then one of the researchers accepted the bread but ate the cheese she was supposed to give to the raven, in effect saying, “Hah Hah Hah! Fooled you!”
The ravens were outraged! Find out what happened next in this vintage article.
Bald eagles are top predators who will eat crow nestlings, fledglings and unwary adults if the opportunity arises, so crows learn from a very young age to watch out for eagles.
Even in the nest young crows hear and see their parents drive off hawks and eagles. In their first year of life, which they spend with their parents, they learn the rules of harassment.
When a lone crow sees an avian predator he perches prominently and calls for reinforcements.
When his buddies arrive the crows work as a mob to drive away the predator.
When the situation is acute and the mob is left behind, a solo crow may harass an eagle even though he’s the only one left. Sometimes he does something daring.
Ten years ago photographer Phoo Chan went to the shore at Seabeck, Washington to photograph the bald eagles who arrive in large number during the midshipman fish run (Porichthys sp). He was very lucky to capture photos of a lone crow riding on an eagle’s back. See more in his article below.
Crows coming to roost near the Carnegie Science Center, 17 Jan 2024 just before 6pm (photo by Carol Steytler)
18 January 2025
Crow news has been coming fast and furious in Pittsburgh this week.
On Wednesday I posted an update (Crow Update, mid-January) even though I didn’t know where they were roosting.
On Thursday many of you responded with your own sightings including this video from Lyndsay Krut on Mt. Washington.
video embedded from Lyndsay Krut on YouTube
Then Friday morning the crows became famous when Pittsburgh photographer Dave DiCello happened to run through their morning staging area and posted his video on Facebook and Twitter. Dave DiCello Photography has 160,000 followers on Facebook. His post went viral.
That was Friday morning.
Friday evening Crow Patrol member Carol Steytler followed crows to the roost and found out they are drawn to Science! — specifically to the roof of the Carnegie Science Center and nearby trees.
Crows gather at the Carnegie Science, 17 Jan 2025, 5:54pm (video by Carol Steytler)
Notice them on the roof edge in Carol’s photo.
Crows roosting near and on the Carnegie Science Center, 17 Jan 2024 (photo by Carol Steytler)
Watch Dave DiCello’s morning video again and you’ll see them silhouetted against the base of the glowing eMotion Cone. Dave also took a daylight photo.
You know it figures: I have a million wintry #Pittsburgh images to share, and then I see a murder of crows this morning and end up sharing that image instead. While it was a bit creepy, I was fortunate to capture a unique view of a crow landing with PPG Place in the background. pic.twitter.com/hjTm0CV7zj
So now we know the crow map looks like this. Pink is morning, orange is evening, and that circle of pink and orange is the roost.
map of Pittsburgh winter crow movements, week of 13-17 Jan 2025 ()
Thank you, everyone, for your sightings.
I’ll be interested to see what the crows do this coming week as Pittsburgh experiences extreme cold with temperatures down to -9°F and wind chills as low as -25°F. And they have to sleep outside. Brrrr!
Crows flying over Riverview area, Dec 2022 (photo by Jeff Cieslak)
15 January 2025
After the big push to find Pittsburgh’s winter crow flock for the Christmas Bird Count in late December I took a break and merely enjoyed them. Searching and counting is hard work so I didn’t look for crows and if I saw them I certainly didn’t count them. Thankfully, you’ve been letting me know what you see.
Fred’s comment yesterday makes me wonder if crows are roosting on Downtown buildings.
Last Friday, 1/10/25, just before 7 am there were thousands of crows flying around and roosted in trees of the little park on First Ave downtown (across from PNC) and perched on all the buildings around. Their collective cawing would have made conversation at normal levels difficult. Having seen similar numbers in Oakland and Schenley in the early evening, made me wonder if they make the pre dawn rally to town.
Pittsburgh’s crows may have split or moved their roost this month and I wouldn’t be surprised if they did. Bitter cold temperatures like last night’s 7°F prompt crows to spend the night on a warm rooftops rather than in bare trees.
UPDATE: check the comments for additional news on 15 Jan.
And here’s a treat for crow watchers: In Lawrence, Massachusetts the Crow Patrol sees crows after dark on roofs and trees using infrared cameras. Notice how crows’ eyes glow white in infrared light.
Crows flying to the roost in Oakland, Oct 2019 (photo by Kate St. John)
29 December 2024
We tried but it was daunting. Last evening Carol Steytler, Claire Staples, Lisa Kaufman and I counted crows coming into the roost near the VA Hospital in Oakland for the Pittsburgh Christmas Bird Count. 15,000 crows. More or less. Probably more.
For an accurate count we needed all these conditions to be met simultaneously and all of them are under the crows’ control. Last night the crows beat us with blobs and darkness.
Know where the roost is.
Know the flight paths they use to reach the roost.
Know the size in the sky of a blob of 100 or 1,000 crows and be able to see the blobs.
Darkness: Here’s what I mean. You can’t see the crow until I alter the photo (from Wikimedia Commons). Nor could we.
Crow in the dark -- photo adjusted so that you can see the crow
Crow in the dark, perched on a branch
Crow in the dark -- photo adjusted so that you can see the crow
The crows used the same roost site (sort of) that we found on Friday: the VA Hospital roof + nearby buildings. Miraculously they didn’t change the roost. However, the roof itself is too high to see so we used flight-path counting from the OC Lot parking deck. I’m sure some were hidden by buildings as they came in and weren’t counted.
Flight paths change day to day but Saturday’s was better than Friday’s from their pre-roost staging site in the west, backlit by the glow of sunset as shown at top. Very soon it was too dark to see black birds in a black sky. And the crows were frequently diverted by Stat MedEvac helicopters flying back and forth from UPMC Presbyterian.
Crow flock flight density — the blobs — changed all the time of course. We saw 100 crows in long strings, in very tight balls, and everything in between. Hard to count.
I’ve been counting crows for the CBC since 2018. It is always a challenge.
p.s. Lisa and I are thinking of practicing the blob-count next month while the crows are still in town. If you have a suggestion for counting you must first count with us this winter. (I’m not kidding!)
If you’re an experienced crow counter no need to join us; we welcome your tips.
Crows roosting near Thackeray Hall a year ago, in 2023 (photo by Kate St. John)
26 December 2024
Two days from now, on 28 December, we’ll try to count all of Pittsburgh’s winter crows for the annual Christmas Bird Count. Unfortunately our efforts to find them have fallen quite short of the number we expect.
I believe there are 10,000 to 20,000 crows in the area but we’ve found only 2,000 to 5,000 in Oakland this week, even though I saw about 8,000 the week before. It is likely that the crows split the roost.
In prior years in Lawrence, Massachusetts their crow roost used to be in one place but this winter their crows have split into three locations. Lawrence Crow Patrol has found them all, as shown in this 14 December video. I wish we could say the same.
Have you seen crows crowded at the tops of trees at night? Have you found lots of crow poop in the morning — a sure sign that they were sleeping there the night before?
Let me know where the crows are sleeping by leaving a comment below.
Snow in Schenley Park, 20 Dec 2024 (photo by Kate St. John)
22 December 2024
In the run-up to the winter solstice the temperature dropped below freezing last week and the clouds moved in. Seen last week includes evidence of deer, snow and crows.
Evidence of deer: After the city parks bow hunt began in September the deer found other places to hang out including cemeteries and backyards. But we still see their evidence of their nighttime presence including this buck rub in Frick Park on 19 December.
Buck rub on a tree in Frick Park, 19 Dec 2024 (photo by Kate St. John)
Snow fell on Friday and Saturday. In this video its starts out a bit furious and then tapers.
Snowing in Pittsburgh on 21 Dec 2024 (video by Kate St. John)
Our search for the Pittsburgh crow roost continues. We need to find as much of it as we can before the Pittsburgh Christmas Bird Count on Saturday, 28 December. So far we haven’t broken 10,000 but we know there are more than that.
Though crows prefer to spend the night in trees we’ve discovered they also roost on rooftops in Oakland where we cannot see and count them. Dang!
Last night Carol Steytler found some near the Pitt Field House. Not a huge number, but encouraging. Her video is dark; it was the middle of the night.
Please help us find the crows. Leave a comment to let me know where you see lots of crows after 4:00pm in the city limits. Tell me about …
Huge flocks of crows
Seen after 4:00pm or Overnight
Where are they? Provide specific location, street or landmark.
If flying, what direction are they going? I’ll map your contribution and triangulate.
Winter crows are incredibly persistent. Year after year they return in large numbers to the same city, even if the city harasses them. Some cities harass their winter crows, some celebrate them. This is a Tale of Two Cities from the winter crows’ perspective — Rochester, New York and Lawrence, Massachusetts.
From the crows’ perspective, smaller units won’t provide safety in numbers so the crows will reconvene somewhere. But where? Will the new location cause trouble, too?
Rochester could choose a more permanent solution by “thinking like a crow.”
Penn State University used to have a big crow problem in the center of campus. In 2009, with the help of crow expert Margaret Brittingham, they picked a location away from people where they wanted the crows to roost. Since crows want to sleep with the lights on, Penn State floodlit a remote set of trees and harassed the crows away from the people zone. The crows moved to the floodlit site and abandoned central campus. Not only that, the crows passed on information about the new roost from crow to crow year after year and continued to use the new roost, not the old one. Ta Dah! Read more at Penn State relocates its winter crows.
Tens of thousands of crows visit Lawrence, Massachusetts every winter but as far as I can tell they have never been harassed there. Instead the roost is celebrated as a tourist attraction, described on the Winter Crow Roost website and YouTube channel.
Nov. 18, 2024: Join us for an unforgettable evening on Crow Patrol under clear skies (55°F, NW winds at 15 mph) as we explore the Merrimack River staging area east of Rt. 495. Witness the incredible sight of American and Fish Crows vocalizing and converging into tree tops in a wild, dramatic display at the east end of Island Street.
Don’t miss this breathtaking show of nature in action! Watch now and share with friends who love the beauty and mystery of wildlife.
So from a crows’ perspective, they’d rather choose Lawrence, MA over Rochester, NY.
(*) p.s. Rochester’s crows are never going to switch to Massachusetts. The two flocks come from different parts of the continent: Lawrence attracts crows along the Atlantic coast flyway. Rochester attracts crows from Canada’s interior and areas south of Hudson Bay.
