MSN: The smartest birds hold the longest grudges! Crows can remember human faces for 17 years
The smartest birds hold the longest grudges! Crows can remember human faces for 17 years
Forbes: A Biologist Explains How Crows Can Recognize Human Faces — Well Enough To Hold Long-Term Grudges
A Biologist Explains How Crows Can Recognize Human Faces — Well Enough To Hold Long-Term Grudges