Be nice to crows and their cacophonous relatives--otherwise, you'll have made yourself a lasting enemy. That's the lesson of a neat study that Michelle Nijhuis reports in this week's Science Times.
Wildlife biologist John M. Marzluff had an intutition that the crows and ravens he had previously trapped for his research recognized him and, so, were harder to catch the second time around. In order to test his theory that these birds recognized his face, he had different people wear the same mask as they trapped and banded birds around his University of Washington campus.
In the following months, when volunteers donning these same masks strolled around campus they were subjected to vocal abuse from the crows. "Neutral" masks, which the crows did not associate with bad times, provoked no response. What's more, these birds had long memories. Two years later they were still scolding the masked figures. In fact, even crows that never had been trapped learned to recognize the dangerous face. Now that's what I call a grudge.