On Monday April 6, 2020, I was birding along Old Bridge Road next to the Ompompanoosuc River flats (= "Pompy") in Norwich, VT, when I heard what sounded like a very loud song of a Common Yellowthroat in a very brushy area. A yellowthroat present in the Upper Valley that early in April would be an extraordinary occurrence, without precedent. However, the sound was not quite "right" so, without ever seeing the songster, I decided it must have been a Carolina Wren.

Then on Wednesday April 8,  I again visited Old Bridge Road when Larry Morin happened also to be birding there. While keeping our appropriate social distances, we both heard an unseen singer giving repetitive calls strongly resembling those of a Tufted Titmouse. Those were followed by a lengthy series of songs like those of a Northern Cardinal from about the same direction. It would have been very easy for us to have chalked up a titmouse and a cardinal because those species are regular in that location. Larry, however, pursued the unseen singer and could find only a Carolina Wren in the area.

Again this morning, April 12, I went to Old Bridge Road where again there was a loud song repeatedly coming from the brush and strongly resembling that  ("witchty, witchty, witch") of a Common Yellowthroat. My conclusion again was that I was hearing an unseen Carolina Wren.

During this same time span, from April 6 to 12, Larry, other observers, and I have from time to time made other visits to Old Bridge Road and not found a Carolina Wren, as indicated in part by eBird reports from Windsor County. Presumably the wren was either away from that area or silent during those birder visits when it was not detected.

The wren at Old Bridge is impressive as a mimic for repeating the same imitated songs at length, unlike mockingbirds which in my experience tend to have less extended repetition. The imitations by the Old Bridge Carolina Wren, to my ear at least, seem good enough at a distance potentially to mislead birders experienced in using vocalizations to identify titmice, cardinals, or yellowthroats.

Despite numerous past encounters with Carolina Wrens in the Upper Valley and elsewhere, I had not realized the potential for vocal mimicry by those wrens.

In 1948 A. C. Bent in his landmark series of volumes on life histories of North American birds wrote about the Carolina Wren that "It has a varied repertoire; the songs of other birds are often suggested, or perhaps imitated, leading to some confusion at times ...." Bent mentions "a loud whistle like that of the cardinal" and a song like that of the Tufted Titmouse. He also mentions numerous other imitated species including Common Yellowthroat. Bent noted that the Carolina Wren has been called the "mocking wren". Bent also quoted Thomas Nuttall, who in a book back in 1832 remarked on the mimetic abilities of the Carolina Wren.

Special thanks to Larry Morin for his critical contributions through listening, observing, and commenting.

George Clark
Norwich, VT









 


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