Observation by John Polo
On Friday, March 2, there was a Hermit Thrush in our yard apparently foraging. It was the first time I saw “our” thrush move to the ground of all its visits (I’m assuming it was the same bird I was seeing a couple of months ago). While it was searching, I noticed its legs shivering. I was close, I was just on the other side of a glass door to the yard, and could see the bird quite well. The shaking was unmistakable. It was just the legs shaking pretty vigorously. I was surprised that a bird would be that cold in weather that was about 44 degrees. I’ve seen juncos and thrushes in snow never twitch at all.
I emailed a couple of ornithologist friends because I thought it was weird to see a bird shiver and one of them came back with a link to a blog that wrote about this behavior in HETH. It appears this is not an anomaly. Here is the link: bootstrap-analysis.com/2006/10/hermit_thrush_a.html