I have trouble seperating the two thrush species here on the coast during our Spring and Fall overlap seasons so I decided to do some observations this winter on wing and tail flicking as a reliable way to differentiate Swainson's from Hermit thrushes.
Last Fall, "Hermie" arrived right on schedule and took up residence in my pygmy forest bushes. Hermie may or may not be male and might not even be the same individual across all sightings, but he is Hermie to me and he stays all winter.
Results: From November through Feburary Hermie was always seen wing and tail flicking. At no time did Hermie not wing and tail flick. The longest measured period of time between flicks was 20 seconds and that was a single unusual event. Then, around the end of February tail and wing flicking decreased until March when a sighting recorded no flicking for over two minutes of continued observation. Hermie was then seen no more and presumably "went up the hill" (or got eaten by a cat).
Yesterday, May 29, a confirmed visual of a Swainson's was seen in the bushes. I've been hearing the Swainson's for a week or two but have not been able to get a good sustained visual observation. There might have been a single tail pump but the sighting was short and didn't last long typical of Swainson's.
Thus begins the summer observations. Do Swainson's wing and tail flick? Preliminary results indicate that wing and tail flicking might be useless for indentification purposes in these two thrush species. Conclusions to follow in the Fall.