Seven years ago I wrote about an endangered member of the crow family in Ethiopia whose range is small and shrinking. Similar in size and sociability to our Florida scrub-jay, Stresemann’s bush-crow (Zavattariornis stresemanni or Ethiopian bush-crow) lives in just 6,000 square miles of southern Ethiopia’s Borana rangelands in an area smaller than New Jersey.
Has the bird’s status changed in the last seven years? No, but we know more.
A 2012 study found that his range was limited by daily high temperature. In 2018 a team of scientists investigated further, taking temperatures throughout the region and comparing the bush-crow’s range to two other local species — white-crowned and superb starlings. Their report at the British Ornithological Union blog showed that Stresemann’s bush-crow has a narrow favorite temperature range and is heat intolerant.
The starlings don’t care how hot it gets but the bush-crow won’t live where the maximum daily temperature is over 30 degrees C (86 degrees F). (Graphs embedded below from bou.org)
This wouldn’t be a problem except that it’s getting hotter.
When thousands of crows come to town for the winter what do they find to eat?
Every morning they wake up in the city and spread out during the day to find food near and far. Some travel 10-20 miles to glean from fields and landfills. Others raid dumpsters, prowl parking lots, or poke holes in garbage bags waiting for neighborhood collection.
Up to 65% of an urban crow’s diet is made up of human food and we sure make a lot of it available. Nothing is faster than fast food, especially fries.
Some crows like to dunk their fries.
They are not daunted by paper bags. In this video by Quiscalus a flock of fish crows fights over a bag of fries until the herring gulls take over. I’ve seen this happen in Virginia Beach.
On my way to meet friends at Moraine State Park last Friday, I stopped to check a few coves for tundra swans. My first stop was better for bird behavior than for waterfowl. As I drove away a ruffed grouse chased my car!
Naturally when I saw a grouse in my rearview mirror, flying after my car, I parked and got out to look. By then he was perched in a tree, strutting and turning his head in an apparent territorial display. I took his picture with my cellphone. He was further away than he appears.
Was he tame? Was he habituated to humans and cars? Was he stocked by the PA Game Commission?
At my next stop I told Linda Crosky and Dave Brooke about my experience. They later went to find the grouse and Dave took photos of his Life Bird (at top).
Dave also did some research and found out that, no, the PA Game Commission probably doesn’t stock them at Moraine but yes, grouse sometimes act this way. Birds like this are few and far between. They are not tame. They are hyper-territorial.
This spring PA Game Commission Ruffed Grouse Biologist Lisa Williams made a video of her visit with a so-called tame grouse. He tried to take a bite out of her.
If “tame” ruffed grouse were the size of T. Rex we’d all be dead.
p.s. Want to see more? Click here for a 2017 video of a “tame” grouse approaching two men in Pennsylvania.
(photo at top by Dave Brooke; second photo by Kate St. John)
As waterfowl arrive on migration it’s interesting to note that some families travel together, others do not.
Bird parents and offspring stay together during a nesting event but among most species the families split up after the breeding season. Notable exceptions are swans, geese and cranes which stay together as a family unit. The youngsters learn the route and wintering grounds from their parents. If their parents don’t migrate neither do they.
Above, a tundra swan family comes in for a landing at Middle Creek. The youngster (gray head and neck) is still following his parents as they head north in the spring.
Each duck species has its own migration strategy but that doesn’t mean they travel in family groups. For many, fall is the time to meet and greet the opposite sex. Mixed flocks of gadwalls (Mareca strepera) pair up while they travel. According to All About Birds, virtually all female gadwalls have a mate by November.
For birds, traveling as a family is the exception.
Some always travel alone.
(photo of tundra swans by Dave Kerr in 2014, remaining photos from Wikimedia Commons; click on the caption to see the original)
Since moving to Oakland three months ago I’ve had a front row seat on the crow population. From a family group of six crows in late July the numbers grew to 200 in mid-August, 1000 in late September, 5000 in mid-October and now in late October 10,000 crows come to Oakland every night. The question that worries everyone who has trees is this: Where will the crows sleep?
Crows roost in mature trees or on flat roofs where there’s ambient light, white noise and no disturbance. They want the lights on so they can see danger coming, especially owls. They like white noise — the sound of traffic, rushing water, or humming fans — but they don’t like sudden loud noises.
About 10 years ago the crows chose Pitt’s campus (photo below, December 2017).
Two winters ago they moved one block north to Schenley Farms, a small neighborhood of mature trees and historic homes where their noise and slippery feces are overwhelming. This year Schenley Farms is going to encourage the crows to sleep elsewhere by making sudden loud noises before the crows settle for the night.
The first step, however, is to find out what the crows are doing. I volunteered for that job and I love it.
I’ve learned that crows move into Oakland almost exactly at sunset, land in final staging areas 1-3 blocks from the roost, and swirl around for 30-45 minutes until they settle.
Last Saturday the crows didn’t choose Schenley Farms but I couldn’t see their final roost west of Soldiers and Sailors because of intervening buildings. On Monday evening at 8pm Michelle Kienholz photographed them roosting on trees and buildings near the Graduate School of Public Health (GSPH).
They’re hard to see in her photo below …
… so I removed the brown and circled them in red. They line the roof edge and the treetops. One is flying in the dark!
So far so good. The crows aren’t sleeping near the Cathedral of Learning. They’re not at Schenley Farms.
There’s still a possibility they could choose Schenley Farms but if they do the residents will use “clappers” like those Pitt has found effective for dispersing crows — simply two boards connected by a hinge that can make a loud clapping sound.
If clappers don’t work Schenley Farms will warn the crows before they roost by making really loud noises — pyrotechnic “screamers and bangers.” So far it hasn’t come to that.
Where will the crows sleep this winter? Perhaps far away.
Let me know if you find them.
(photos by Kate St. John, Joanne Tyzenhouse and Michelle Kienholz. Clappers photo via Alex Toner at Univ of Pittsburgh)
When you see a bird eating white berries from a hairy vine you might not realize it’s eating poison ivy. Birds are blissfully immune to the urushiol in poison ivy sap that gives us humans a nasty rash.
By late October poison ivy (Toxicodendron radicans) doesn’t look like the plant we’ve been avoiding all summer. The leaves are red or missing, the vine is exposed, and bunches of white berries hang from the branches. It’s easy for migrating yellow-rumped warblers (Setophaga coronata) to find the food they’re so fond of.
In eastern North America our chimney swifts (Chaetura pelagica) land every evening to roost in chimneys. In Eurasia and Africa the common swift (Apus apus) stays airborne for 10 months of the year!
No one knew this until Lund University in Sweden attached geolocator tracking devices to common swifts in 2015. When the swifts returned from their winter range in Africa the Swedes recaptured the tagged birds and found that most had not landed since they left!
Since common swifts spend so much time in the air and can live for 20 years an individual swift may fly 3 million miles in his lifetime. Wow.
(image from Wikimedia Commons; click on the caption to see the original)
Now that the breeding season is over birds have gathered for migration and the winter.
Early this week 50 common grackles leapfrogged over the trees and forest floor as they searched for food and bathed in Panther Hollow Run. (This photo gives you an idea of their abundance.)
Cedar waxwing numbers peaked in Schenley Park in early October when they devoured most of the porcelain berries. They’ll spend the winter further south, for instance in Memphis, Tennessee where this photo was taken.
Pine siskins were everywhere a couple of days ago. Are they still visiting your feeders? Where will they head next?
Starlings numbers are building in Pittsburgh as northern visitors arrive. Soon there will be thousands.
Crow numbers are building too. Last weekend I counted 2,400 but more arrived last night. Eventually the flock will look like this video from 2011. Where will they roost? Stay tuned.
Watch for spectacular flocks this fall. Let me know what you see.
(photos from Wikimedia Commons and Mr. T in DC, video by Sharon Leadbitter. Click the captions to see the originals)
The most numerous wild bird on earth, estimated at 1.5 billion individuals, is the red-billed quelea (Quelea quelea) of sub-Saharan Africa. This very social weaver finch migrates and nests in flocks that number in millions.
When the flocks get going they resemble swarms of locusts.
Red-billed queleas eat mostly grain and seeds. As they feed on the ground the flock leapfrogs from back to front like a rolling cloud.
In Africa they are so well known as flocks that it’s hard to think of them as individuals. Two males are pictured above. Here’s a female.
This species is a major pest of cereal crops, and huge efforts have been expended by national and international agencies on lethal control and attempts to reduce population numbers by use of explosives, petrol bombs and aerial spraying of [organophosphate] avicides; in South Africa up to 21 million reported killed in a single month, with annual kill estimates of up to 180 million.
Control operations, however, probably do no more than replace naturally occurring mortality, and there is a significant adverse impact on other species, which are poisoned directly or die after eating dead queleas.