Migration, birds fly south at different times of the year this depends on how far they live and when their food supply is dissapearing.
It's called migration.
The temperatures are warmer closer to the equator.
convection current
Starfish prefer warmer waters rather than colder waters.
colder
Thermal Layer
Warmer
Hot in the summer and then it get colder and colder over the fall and in the winter it get's really cold some places, but rains in other places. And finally it gets warmer during spring, however a bit chilly in the begining.
Very much colder.
colder
Generally warmer.
warmer