Thousands of years ago, a large flock of hawks was driven from
its normal migratory route by a severe storm. The birds scattered
and found shelter on two distant islands, as shown on the map
below. The eviornment of island A is very similar to the hawk's
original nesting region. The enviornment of island B is very
different from that of island A. The hawks have survived on
these islands to the present day with no migration between populations