Emperor Penguin Rookery in Antarctica

Emperor Penguins like to position their rookeries in the vicinity of grounded icebergs, like the one visible in the background.  Much of the Antarctic coastline is one big glacier.  The dynamics of this glacier ice typically create an ice flow 600 feet thick.  When this ice reaches the coast it doesn't stop, it continues on for miles into the ocean, creating gigantic ice shelves.  Occasionally pieces of this ice shelf break off creating 600 high ice bergs.  These bergs float about a 100 feet high and with about 500 feet underwater.   Whenever these ice bergs drift into water 500 feet deep they ground themselves on the bottom and that's where the Emperor Penguins like to setup housekeeping.