Rookery

The Dragon Breeding Island, also called Egg Island or New Birth Island by some fans, officially called The Berkery was shown in the short Gift of the Night Fury when all the Dragons of Berk, along with thousands of other wild Dragons left on the annual holiday, Snoggletog to lay their eggs and care for their young until the babies have matured enough to take care of themselves. It hasn't been proven that these dragons do not return back to lay more of their eggs.

Geography and Physical Landscapes
The Berkery is a large island with a circular lake in its middle surrounded with pristine golden sand. The lake is encircled with rocky mountains and steep cliffs. The island has many hot water pools with underground water in it. Gronckles push their eggs into them to suppress the explosive action the eggs produce when hatching.