
Crows are birds that are able to remember the
faces of people who pose a threat to their own kind. Also they can
invite other crows to join them to take revenge on the attackers.
Crows can bring their bad experience with some people to the wider
population of crows, says co-author of study John Marclaf at the
University of Washington. Intrigued by the behavior of the crows living
on their campus in Seattle, Marclaf and two colleagues wanted to
determine whether the bird will remember the person they have
experienced a traumatic experience.
For their experiment the
scientists with thesame masks had putted the rings on the captured
birds, and then let them free. Thenthey watched the reactions of crows.
The moment they saw the mask, the crows began to caw angrily, waving
their wings and come together in a threatening crowd.
If, traveling
to other parts of the city, the researchers placed the same mask on
their faces, crows that they have never previously captured would have
recognized the dangerous faces. Crow behavior demonstrates that birds
learn not only fromdirect experience, but also through communication
with other members of the species.
During a five years of research,
scientists have extended the experiment at several locations, using the
other masks. Regardless of the change of masks, there are more crows
reacted to the arrival of dangerous persons.
Alert is not just
spreading only to the neighborhood crows, but also a young crows,
observing the reactions of their parents, began to imitate them.