The amazing photo below of an eagle’s claw and a human hand left me wondering, Who is this bird and why are his claws so big? Today I’ll tell you a bit of his life story.
Shaped like a giant goshawk with a feather crest, the crowned eagle (Stephanoaetus coronatus) lives in the riparian forests of sub-Saharan Africa where it eats monkeys, small forest antelopes (duikers), “mouse-deer” (chevrotains) and “rock rabbits” (rock hyrax). Click on the links to see photos of these unusual animals.
Crowned eagles weigh only 6-10 pounds, smaller than bald eagles, yet they routinely capture mammals twice as heavy as they are. Reports say they can fly with prey that outweighs them, but they normally rip it apart on the ground and cache pieces in the trees. For this lifestyle they need large talons.
For thousands of years people have known that certain sand dunes make a low humming sound, the musical note of G, E or F. It occurs when the sand is moving but you can force the sound if you slide downhill. Why does it hum?
A decade ago scientists at CalTech studied two humming sand dunes in California to answer that question. They found that for the sand to sing, the grains have to be all the same size, the dune must have a slope greater than 30 degrees and be over 120 feet tall, and the sand must be dried under the desert’s summer sun. It was very hot work.
The humming sound occurs naturally when the sand moves but that doesn’t happen on a predictable schedule so the CalTech team forced the sound. Dr. Melany Hunt explained,
Usually we would trigger it by having a number of people slide down the dune in unison. We always called it ‘Science by the seat of our pants.’
We’re often so mesmerized by the ant’s struggle that we forget she has an additional challenge. She has to navigate while walking backward. Ethologists at Paul Sabatier University wondered how ants do this so they baked some cookies and ran some tests.
Using a nest of Spanish desert ants (Cataglyphis velox) the scientists laid out large cookie pieces for the ants to find. Without disturbing the ants’ paths scientists noted how often they turned around to check their bearings. They also “airlifted” some ants away from the nest (no path to remember) and messed up the scenery for others so the path would look different.
To give you an idea how hard this is, imagine walking backward without the help of handheld Google/Apple maps. How often would you turn around to check where you were going? And what would you do if an enormous hand rearranged the scenery and nothing looked the same?
Some of the confused ants never made it, but those who knew their path walked 6 meters without peeking. This is equivalent to a human walking backward without peeking for the length of two football fields.
Perhaps it helps that ants can see nearly 360 degrees around their heads. Despite all the challenges they still get home.
For temperature, the redder the color the more likely it will be hotter than normal. For precipitation, green means it’s likely to be wetter. Pittsburgh is high in both categories, hot and wet. So is Alaska, especially in temperature.
Since we don’t have hedgehogs in the U.S. you might not realize what a loss this is.
Only half the size of house cats, European hedgehogs (Erinaceus europaeus) have soft spines that are prickly but not dangerous. Unlike porcupine quills the spines have no hooks. Here’s a young one held in the hand.
Though they are nearsighted, nocturnal and solitary, hedgehogs are blessed with a keen sense of smell that helps them find beetles, slugs, insects and grubs. In summer they are lightweights (1.8 pounds) but in autumn they double their weight to get ready to hibernate.
There are perhaps just a million left, representing a 97% fall from the 30 million estimated to have roamed in the 1950s.
No one’s sure why hedgehogs have declined so precipitously but theories include a lack of habitat, a lower insect population, pesticides, road kills, and an increase in predators and competition, especially from badgers.
On Friday afternoon January 3 Bob Mulvihill, his son Anthony, and I visited the Cathedral of Learning to make sure the falconcams are ready for the 2020 nesting season. Bob checked the cameras, wiped the weather-proof domes, and removed those reddish circles from the nest.
We saw Morela on our way into the building, perched on a gargoyle spout on the 32nd floor. She stayed where she was. The day was too foggy to be flying high.
Yesterday, January 4, was still foggy and rainy but Morela was intent on courting with Terzo. At 10am she called from the nest, “Come court with me.”
At noon she and Terzo bowed for two minutes. Terzo is in the back corner below (notice his bands). Morela has her back to us.
The peregrines, too, are getting ready for the nesting season. I can hardly wait for the falconcam to start streaming next month.
Sometimes we think Pittsburgh is boring in January but there’s still a lot to see outdoors. On New Years Day I joined the Botanical Society of Western PA for a walk in North Park. Here’s what we found.
Above, black privet berries (Ligustrum genus) stand out against the sky. Privet, an invasive plant, is found at the old farm along Irwin Road. The house and barn no longer stand but ornamental trees and shrubs remain, including the Ozark witchhazel (Hamamelis vernalis) we always trek to see. Our hike leader, Richard Nugent, said it will bloom pink in February. Here’s a bursting bud.
Unusual trees caught our attention, some with burls, others with holes. Two of the best are pictured below.
We also saw and heard red-tailed hawks circling overhead. (example photo below)
In January they claim territory with lots of circling and screaming. Here’s what they sound like. No, that is not the sound of an eagle.
During winter expect the unexpected. There’s more to see than you’d think.
(plant photos by Kate St. John, red-tailed hawk photo by Melissa McMasters via Wikimedia Commons; click on the caption to see the original)
At mid-morning on New Years Day, the sun came out, the temperature rose above freezing and the winds gusted to 29 mph — perfect weather for Pitt’s peregrine falcons to stretch their wings.
In the early afternoon Morela visited the nest for twenty minutes. At first she bowed as if to her mate, Terzo, but he didn’t appear on camera. She scraped at the gravel, watched and waited, then preened on the front perch. This is Morela’s longest visit to the nest since she arrived at the Cathedral of Learning last September.
Streaming video isn’t available yet but the snapshot camera captures photos every 15 seconds. I’ve put the best ones in the slideshow below.
The best place to see Morela and Terzo this month is in the air above the Cathedral of Learning. Watch for their breath-taking courtship flights as they prepare to nest in March.
p.s. Morela visited the nest for only a minute yesterday, 2 Jan 2020.
For many years now my First Bird of the Year is always the American crow because hundreds fly over my house before dawn, cawing as they disperse from the roost. The only way a different species could win “First Bird” is if I cheated and ignored the obvious.
This year I decided to change the challenge to Best Bird of the First Day. My 2020 winner is the turkey vulture that used to be absent on January 1.
Turkey vultures (Cathartes aura) are South American birds who’ve expanded their range into North America, year-round residents in the southern U.S. but only summer visitors up north.
Vultures migrate because they can’t eat our winter food supply. Though carrion is available year-round their beaks aren’t strong enough to rip open frozen food.
However climate change is doing them a favor. Last month in Pittsburgh most days were barely below freezing and five recent days were as much as 20 degrees above normal. Nothing was frozen.
Turkey vultures used to leave Pittsburgh for the winter but in this century a few began to linger here. The most reliable group roosted within sight of Dashields Dam on the Ohio River. Last month additional vultures were reported during the Pittsburgh Christmas Bird Count. Even so, I was surprised to see two of them soaring over McKnight Road on the first day of the year.