The orange oakleaf butterfly (Kallima inachus), native to tropical Asia, is well named. The underside looks exactly like a leaf when the butterfly closes its wings, and it has wet and dry season forms that mimic the leaves of each season.
We have leaf-like butterflies in North America, too. Click to see the ventral and dorsal sides of the goatweed leafwing (Anaea andria). It ranges from southeastern Arizona to southern Ohio.
(photos from Wikimedia Commons; click on the captions to see the originals. video from Red Cache World on YouTube)
Why do so many soaring birds and seabirds have white wings with black tips? For starters, black plumes are more durable than white ones, providing an advantage at the tips. New research this summer shows another possibility.
A study at the University of Ghent determined that the black-and-white color combination generates extra lift because of the temperature difference between the colors.
Using taxidermied wings, a heat lamp and a wind tunnel, the researchers measured airflow over the wings in a variety of wind conditions. They found that:
… dark feathers grew hotter than lighter colored feathers and they also gained heat faster than lighter colors. The researchers found temperature differences as great as nine degrees between black and white feathers on the same wings—enough to create a convection current in the air just over the wing, moving from the bird’s body outward along the wing.
The study described a convection current that works like this.
Differential heating creates a convection current just over the wings (photo of American white pelican from Wikimedia Commons, annotation by Kate St. John)
American white pelicans and northern gannets both benefit from this additional lift.
UPDATE: SUNDAY’S OUTING ON 27 OCTOBER IS CANCELED DUE TO RAIN AND GUSTY WINDS. Join me at 8:30a on Tuesday 29 October for a raincheck outing at Duck Hollow.
Waterfowl move south when the lakes freeze up north. Will migrating ducks be in Pittsburgh by late October, or will the weather to our north still be too warm? Let’s get outdoors to find out.
Join me on my last outing for 2019 at Duck Hollow by the Monongahela River.
When: Sunday 27 October 2019, 8:30a-10:30a.RAINCHECK: Tuesday 29 October 2019, 8:30a-10:30a.
Morela at the nest, 17 Oct 2019 (photo from the National Aviary snapshot camera at Univ of Pittsburgh)
Now that the new female peregrine at the Cathedral of Learning has been on site for more than six weeks and has actively claimed the nest, it’s clear that she is no longer “new.” Meanwhile, it’s too vague and unwieldy to call her “the female peregrine at the Cathedral of Learning.” So today she gets a name.
The primary nest monitor names the bird for his/her own convenience using these two rules. If the peregrine was named at banding that name is preferred. Otherwise the primary monitor names the bird.
As an unbanded peregrine she didn’t come with a name so it was my job to decide what to call her. After many hours of deliberation with my fellow peregrine monitor Karen Lang, the new female peregrine at the Cathedral of Learning has a name: Morela.
It’s a tribute to the pale orange color of her breast, belly and cheeks. Morela means “apricot” in Polish.
Pale apricotMorela has a pale orange breast in every light
New female peregrine at the Cathedral of Learning nest, 17 October 2019, 10:22a (photo from the National Aviary falconcam at Univ. of Pittsburgh)
Though she isn’t going to lay eggs until next year, the new female peregrine at the Cathedral of Learning spent a long time at the nestbox on Thursday morning, 17 October 2019.
This video of Thursday’s activity is long — 8.5 minutes — but it shows the most interesting part of her visit, captured at 10:10am on 17 Oct 2019. The video will seem to run forever. Pretend you’re watching it “live.”
Two more videos round out the 14 minutes, not including the time she sits on the front perch. Click the links for:
These unusual clouds are called fluctus or Kelvin-Helmholtz clouds. They occur when Kelvin-Helmholtz instability is present in the atmosphere, caused by a difference in temperature and wind. The air below the clouds is moving slowly, the air above them is moving fast. Since it’s an unstable condition, the clouds soon disappear.
Last summer Kelvin-Helmholtz clouds appeared over Smith Mountain Lake, Virginia on 18 June 2019. Meteorologist Chris Michaels at WSLS 10 News explains them in the video below.
Visit this vintage blog, Making Waves, for a video that shows what happens when the waves break.
(photos from Wikimedia Commons; click on the caption to see the original. Video embedded from WSLS TV)
Today in Pittsburgh it’s “cloudy” but a better description would be gloomy. Gray skies are depressing. How can we cope? Let’s look at yellow.
In an ongoing international survey (6,625 people in 55 countries to date) participants are asked, “What emotions do colors represent?” The data shows that most people say yellow is joyful but this isn’t true worldwide. It’s very joyful in the United States, exceptionally joyful in Finland, but in desert regions it’s not.
They found that environment and cloud cover matter. The sun is not your friend in hot, dry, cloudless places. The study aptly named itself, “The sun is no fun without rain.”
Finland loves yellow. I think I know why. The first time I saw an intense field of yellow, like the one shown at top, was in Finland. I made my friends stop the car. So yellow! So happy! What is this plant? Rapeseed!
New female peregrine at Pitt visits the nest for the first time, 14 Oct 2019, 7:24pm (photo from the National Aviary snapshot camera at Univ of Pittsburgh)
16 October 2019:
Good news for Pitt Peregrine Fans!
The new female peregrine, first seen in September by Dr. Alan Juffs, has made an important step at the Cathedral of Learning. On Monday evening 14 October 2019 she visited the nestbox for the first time.
Pete Bell of Pitt Peregrines Facebook page sent me the photo at top from the snapshot archive. I pulled the archived video and cropped it to the time span of her visit.
Japanese barberry, Moraine State Park, 13 Oct 2019 (photo by Kate St. John)
October weather is here and the trees are starting to change color in southwestern Pennsylvania. On the ground I found additional evidence of autumn last weekend.
Burdock, nature’s velcro, is still in bloom. The tiny hooks coating the sepal will soon dry out and cling to your clothes as you pass by.
Burdock still blooming, Moraine State Park, 13 October 2019 (photo by Kate St. John)
Though burdock (Arctium minus) is an alien invasive, a local insect has found it tasty. Notice the trail of the leaf miner, highlighted below.
Burdock with leaf miner activity, 13 Oct 2019 (photo by Kate St. John)
Meanwhile a native plant called Lycopodium or groundpine is in autumn dispersal mode. It has sent up tall pale green structures called strobili that will release the plant’s spores(*).
Lycopodium, Moraine State Park, 13 Oct 2019 (photo by Kate St. John)
(*) Spores definition from Google dictionary: Spores are minute, typically one-celled, reproductive unit capable of giving rise to a new individual without sexual fusion, characteristic of lower plants, fungi, and protozoans.
