"Mobbing" of a Bald Eagle by smaller hawks.
Individual Hawks are small
but much more maneuverable than the Eagle. A group of hawks
can drive off the eagle, with the danger to any single hawk be
much less than if he attacked alone. Especially if the Hawks
are related, such group behaviors may evolve under Kin
Selection if the overall benefit to the kin group is greater
than probability that any one hawk will be killed.
Figure © 2013 by Sinauer; Text material © 2017 by Steven M. Carr