Day 12: Yep, it's time to break out the winter clothes. A few light frosts had already touched my garden, not enough to knock the raspberries entirely out of commission, but I could tell by mid-afternoon yesterday that the overnight temperature was going to take a plunge, if perhaps not all the way to 22 degrees as has been forecast. It didn't miss by much. My weather station recorded 26 for the low, and I was glad I'd dug out my fleece nightgown and put an extra blanket on the bed. But I am not the only one changing into my winter garb. The Goldfinches have lost their summer glow and only their white wing-bars make them instantly recognizable among the other LBJs in the yard (that's "Little Brown Jobs" in birder parlance). A close encounter yesterday when one nearly landed on me as I was filling the feeders inspired me to wonder what triggers the change in some birds and not in others. I did a fair bit of information-mining, and the consensus is that we don't really know for sure. It is believed to be keyed by photoperiod insofar as timing is concerned, i.e., length/strength of daylight, but schools of thought are divided as to whether it is related to camouflage and/or thermal efficiency. There simply hasn't been much research done on the subject. Oh, if only I were fifty years younger! There are so many questions I want answered, so many "whys and wherefors" without adequate explanations. This, my dear readers, is why I write these natural-history posts: to inspire you to guide your children into pursuing education in the sciences and perhaps even to become the scientists of the future. Maybe one of them will find out why the vivid Goldfinch puts on such drab winter clothes.
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