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ASCM October, 2010 Nature Walk |
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Thanks to Ron Polniaszek for this report on our October Fall Migration Nature Walk!
It was a perfect autumn morning; the skies were clear, the wind crisp and temperatures were in the low 50's. Perhaps it was too perfect, for only five hikers were interested in taking advantage of this great day to stroll through the Fred J. Archibald Audubon Sanctuary. For those that did, the annual fall color extravaganza was well under way. The shorter days and colder nights was the signal for the trees to begin to shut down their food production. The trees withdraw some of their precious chlorophyll into the twigs and trunks, and revealing the true colors of the leaves as the rest of the chlorophyll breaks down. The chlorophyll now no longer masks the carotenoid pigments in the leaves that account for many of the oranges and yellows that are seen each autumn. The final step in shutting down for the winter is to weaken the bond between the leaf and the twig; the minute vessels that carried sap all summer are sealed off, and the leaf falls; torn by the wind or simply giving in to gravity and its own weight. The dormant chemical reaction within the leaf now is decomposition, and the flaming hues of autumn quickly fade to brown on the forest floor. What a show, and it is repeated each fall! The morning started out with greetings from about a dozen Eastern Chipmunks who scurried in the understory all around us with their tails straight up. Their call notes included a bird-like chip and a low, repetitive clucking. An Eastern Cottontail led the way down the path to the meadow where our walk began. The action soon started when a kettle of about a dozen Red-tailed Hawks rose out of the trees after spending the night at the sanctuary. The suns rays were creating a thermal over the meadow that the hawks will use to ease their migration flight south. More hawks soon joined in on the rising thermal; Red-shouldered Hawks, Cooper's Hawks and Sharp-shinned Hawks. Streaming overhead were flights of south-bound Blue Jays. As the morning warmed up, Turkey Vultures and Black Vultures took over the soaring duties. A side-by-side comparison of field marks on these huge birds was a good opportunity to distinguish one species from the other. The meadow's warm season grasses were drying out as were the thistle plants, so the butterfly show that we had experienced in August was over. But we did manage to spot a few Monarchs, Common Buckeyes, Cabbage Whites and Little Yellows. We also spotted 28 bird species along the woodland edge pathways and while hiking down along, and through, Cherry Run, the stream that runs through the sanctuary. Of note, we saw Common Yellowthroats, Northern Flickers and lots of White-Throated, Field and Song Sparrows. White-tailed Deer frequently checked us out as they quietly foraged for acorns. Altogether it was a very pleasant, fall morning. We are already looking forward to the next sanctuary walk. Nature always manages to put on a great show for anyone who cares to take the time to appreciate it. Ron Polniaszek, Trip Leader |
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