In this natural history note published in the Canadian Field-Naturalist, colleagues and I describe a “highly anomalous” song we heard while out birding in a marsh around Ottawa, Ontario. The very strange two-note song piqued our interest, and we were surprised to see it coming out of a male Red-winged Blackbird doing a typical territorial display, but sounding not at all typical! We recorded it on two separate occasions- you can listen to what it sounded like here on left, recorded by lead author Brandon Edwards and accessioned in the Macaulay Library. Compare the sound and spectrogram to a more typical song on the right:
In the paper we review the various possible causes for aberrant bird song known in the literature, including malnourishment while young. We speculate that in this case, however, the bird was likely deaf from a young age. Though this is possibly just one idiosyncratic example, this highlights the importance of always being on the lookout for new and strange things around you- each little natural history note contributes to a constellation of data points that can show us how the world is changing or how our original thinking might be wrong!