26 marzo 2015
Why does it seem as if a dark band ripples through a flock of European starlings that are steering clear of a falcon or a hawk? It all lies in the birds’ ability to quickly and repeatedly dip to one side to avoid being attacked. For a split second, these zigs change the view that observers on the ground have of the birds’ wings to cause a so-called agitation wave. This evasive strategy is copied as quick as a flash from one neighboring bird to the next.
http://feeds.sciencedaily.com/~r/sciencedaily/~3/ehMNb1TRHQ8/150326110956.htm
