For an updated explanation with more photos and a schematic, click HERE. "On Dec 19, 2016, Arlene Koziol sent a photo to John Kutzbach, with this message: "There was a mirage on Lake Mendota today. this was taken at Marshall Park. Thanks for teaching me about mirages John!" Here is the photo and John's answer, and if you have anything to add to round out the explanation, please click COMMENT below. "Arlene,
This picture is fantastic. It captures not only very interesting light refraction, but much more. The sharpness of the birds and the slight blurry look in the refraction zone gives it the look of an impressionist painting. You are amazing!! I wish I could explain it all. It is certainly caused by the very cold air almost in contact the warm water. The light rays bend toward the denser (colder) air as they follow the path from the object to your eye (or camera eye). In simple cases this just produces a ‘lengthened’ or ’shortened’ image of the actual object. In this case the ‘lengthened’ ‘cliff’ appears to me to be a combination of a ‘superior’ (upright) and ‘inferior’ (upside down) view of the object. The symmetry line is a horizontal line in the middle. Notice how the top and bottom of the 'lengthened cliff' are nearly exact replicates of each other - but the lower half appears inverted. If this ‘guess’ is correct, then the light rays coming from the object are actually following two paths: one is concave - this gives the upright image; one is convex - this gives the inverted image. The eye, or camera, sees both light ray paths at the same time. The two paths suggest that there is a layer of air with maximum density — and that slightly less dense air is below (at the water) and also some distance above the layer of maximum density. Since I wasn’t there some of this is guesswork. I don’t think the sideways ‘bending’ is a bending, but rather we are just seeing the upright and inverted images with the symmetry line in the middle. (Refraction should in this case - over a broad uniform temperature lake - be strictly a vertical effect and no reason for bending in the vertical ). The slight blurry look is I think an indication of some turbulent micro-eddy activity because of the extreme temperature differences between the warm water and the cold air. The cold air is being heated by the warm water below, but is always being replaced by more cold air. There may also be some water vapor present. These are all pretty much guesses because I don’t know exactly how the scene looks with ‘normal’ temperature conditions. In any case, I think you captured a very, very, very interesting mirage — I think a double mirage. Since both the superior and inferior parts are stretched and neither looks the way the object ‘normally’ looks. I agree the water does appear to float upward - this also is a refractive effect but I don’t immediately understand the light ray path that produces it. John" See more of Arlene's stunning winter photos at: photos https://www.flickr.com/photos/29411257@N00/albums/72157676255638762
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What a sight on Thanksgiving morning - healthy trees had been transformed overnight into hazard trees for ducks passing by along the shore line. Beavers had been hard at work and were not yet done with the tree felling along Picnic Point path. A morning jogger tried to get a feel for beaver feasting. A beaver has large, sharp, upper and lower incisors, which are used to cut trees and peel bark while eating. The incisors grow the entire life, but are worn down by grinding them together, tree cutting, and feeding. The beaver’s incisors (front teeth) are harder on the front surface than on the back, and so the back wears faster. This creates a sharp edge that enables a beaver to easily cut through wood.
This has been a most unusually warm fall. October temperatures were 5°F above average, and the warm weather has been continuing into this first week of November. There has been no frost yet this fall in the Madison area. The last weeks of sunny days brought out the most spectacular fall colors, and with no strong winds, the leaves are hanging on. People visit the Preserve in droves. We met a couple this morning who came all the way from Iowa to stroll from Frautschi Point to Picnic Point and on the Willow Creek. The photo walk below gives an idea of what they saw. Photos Kutzbach
Early throughout its first week of installation, the new kiosk at the entrance to Picnic Point was much appreciated by visitors. Even though many of them know where they will walk, a map helps them to visualize where they are right now, how far they will go and what they will see on the way. Another panel of the kiosk has information about the Preserve and a listing of the Friends field trips. Large stones arranged casually around the kiosk invite to sit. The new bike rack is much used during these sunny fall days, and the wooden entrance gate between the great stone wall pillars is pleasing marker for visitors that they are now entering the Preserve. Native plantings next spring will further enhance the entrance. Well done. Kudos to the Preserve staff for this installation.
Arlene Koziol was photographing the group of bikers who set out on field trip with Daniel Einstein at Willow Creek Bridge on Sept 18. Jeff, one of the bikers, noticed a Green heron fishing in the bay waters. Arlene got some good shots and then returned the next day equipped with her birding camera gear. This is what she reports: "Lake Mendota, University Bay, UW Lakeshore Nature Preserve. Sept 19, 2016. I had a great time watching the acrobatics of a Juvenile Green Heron foraging. It was catching sunfish and large-mouthed bass (fish ID’d by John Magnuson). Patience is the Green Heron’s virtue and the key to his unique fishing technique. The Green Heron would remain motionless, like a statue, waiting for a fish to swim by. His strike was so fast, my eyes could not see it. Only my camera could capture the action." For the entire sequence of photos, see Arlene's Flicker site. The elusive Green Heron is the symbol of the Friends of the Lakeshore Preserve. When the Friends organization was formed about 15 years ago, Roma Lenehan reports, they contacted Kandis Elliot, the then senior artist for the UW Zoology Department, to create a logo. Roma said “the Green Heron seemed to fit us best". The nature drawings on the membership renewal cards you receive in the mail, are also by Elliot (see more of her drawings and posters at the Zoology Museum site) The next time you walk the path to Picnic Point, you will where our volunteers did some heavy lobbing and sawing, lifting to clear a dramatic view for you. Remember, after passing the high sedges on the right of the path, your view is still blocked by heavy underbrush of buckthorn. But now, within a few yards, two dramatic view open up toward the lake and across the beautiful Bay. At the first, you will admire thousands of water lily leaves that carpet the water surface, gently swaying in the breeze. At the next opening, you can catch a glimpse of the American coots assembling for fall feeding. We can thank our hard working volunteers, Galen, Doris, Pat, Monica, Steve, and others led by Preserve volunteer coordinator Bryn Scriver. Photos Galen Hasler .The Preserve’s resident Sandhill Crane family has been showing off their colt these last two weeks on the meadows west of the Class of 1918 Marsh. Papa crane would occasionally look around, checking for potential danger, while Mama crane was doting on their colt, now larger than herself and feed him choice tidbits found in the wet marshland. The three didn’t mind human joggers coming by, we noted. But when some playing dogs came closer, the they stalked slowly the other way. And then, like magic, all three took off simultaneously and flew across the marsh to the other side, elegantly flapping their wings. We were witness to “Wildness Incarnate”, as Aldo Leopold wrote in his poetic Marshland Elegy. We had watched the colt as a little chick, still covered with down feathers earlier in June. In Sandhill Cranes, these soft feathers are replaced about two months after hatching as their cinnamon-colored juvenile plumage grows out from the base of the same feather. In turn, the juvenile plumage will be molted and followed by the first gray winter plumage. Young colts are ready to take their first flight within 10 weeks, and we can assume that this healthy colt is about 3 months old. Led by Jumping Worm researcher Katie Laushman (UW Nelson Institute, Environment and Resources), the entire Pairie Intern crew and UW Preserve staff were out today to begin monitoring the presence of Jumping Worms in the Preserve. They first tested the large leaf compost pile accumulated from deliveries of leaf pick-ups by the Village of Shrorewood Hills. After establishing the presence of Asian Jumping Worms at the bottom of the pile, the crew fanned out into Bill's Woods to survey for the presence of the undesirable worms in the Preserve, if any. To learn more about the worms, their spread in Wisconsin and Best Practices to minimize spread, read the UW Arboretum Public Information Sheet. Katie Laushman studies the effect of Jumping Worms (Amynthas spp.) on above-ground woodland vegetation. Photos Gisela Kutzbach.
The other day we spotted the Prairie Interns at the end of their work day, all happy about a day's hard work in the sun. Adam Gundlach of the Preserve staff, who coordinates their work, had stayed behind to finish the job. When we caught up with him and ask him for his secret to keep the crew so cheerful, he remarked, " Oh, today we pretended to be ahead of elk foraging for juicy saplings in the grasses of the old field." Now all this saplings and out-of-place underbrush are gone and the old field looks like a field again, whirring with dragonflies and other critters. Thanks, Adam! Photo Gisela Kutzbach |
AuthorGisela Kutzbach and contributors Archives
May 2022
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