In a section on Bigfoot in Abominable Science: Origins of the Yeti, Nessie, and Other Famous Cryptids (with Donald R. Prothero), Daniel Loxton writes about misidentification errors:
One fundamental problem with eyewitness tales of Bigfoot encounters is that people make up stories. Another, even larger problem is that people make mistakes. As Grover Krantz noted, “With enough imagination almost any object of about the right size and shape can be seen as a sasquatch.”
Loxton then relates a story about what occurred to him and his fellow hirelings who were acting as shepherds in British Columbia near the Alaskan panhandle, three people shepherding 1,500 sheep on a tree plantation. He writes:
One day, I returned to the flock to find shepherds Jill Carrier and Jolene Shepherd (a much remarked-on coincidence, that surname) talking excitedly. “While you were gone,” they began, laughing a little nervously, “we, uh, saw a Sasquatch.” They hastened to add that they were, well, pretty sure that it was a tall stump. After all, it stood still for a very long time, and half-burned stumps and broken logs are everywhere on overgrown clear-cuts in British Columbia. Such logging debris (slash) can look like anything. A Sasquatch is a perfectly predictable occasional illusion, although this time it was especially compelling. The women laughed, confessing that they could have sworn that the Sasquatch turned its head to follow them.
I will not keep you in suspense. It was indeed a stump. (We were able to examine it later.) But the illusion from the original vantage point was very powerful. Even staring right at it, we could not be sure that it was not a Sasquatch. If we had not had the chance to check it out, this sighting could well have become a strong case for the existence of Bigfoot. Think of it: an extended, broad-daylight sighting by multiple witnesses, all of them experienced outdoor professionals. And memory is collaborative and malleable. If we had left the plantation at the end of the summer believing that we had seen a Sasquatch, our memories of the event would have “improved” over time.
Loxton goes on to relate other misidentifications they experienced as shepherds, such as when he mistook sheep for bears once, and vice versa, and when one of his team mates thought she was seeing a dog and went to chase it away from the flock, only to find herself face to face with a mother grizzly and her two grown offspring