A nest holds dragon eggs to incubate. If the egg is ready to hatch, a READY button will appear on top of the egg. At this point, you may tap on the nest to place your newborn dragon in an available habitat. If you don't have an available habitat which isn't full, a 'buy a new habitat' button will show instead.

You may buy a total of four nests. The first one comes with the game (free), while the rest cost an increasing amount of gold.

Dragon Islands

Nest "Dragon eggs require a Nest to incubate. Acquiring a second Nest is the only way to grow two eggs at once!"
Nest # Lvl. Unlocked Cost
1 1 0 Gold20px
2 2 250 Gold20px
3 7 500 Gold20px
4 16 1000 Gold20px

Arctic Isles

Frozen Nest "Wrap your Dragon Eggs up tight! In order to hatch Ice Age Dragons, they need to be snug as a bug in a rug."
Nest # Lvl. Unlocked Cost
1 35 0 Gold20px
2 ? 250 Gold20px
3 ? 500 Gold20px
4 ? 1000 Gold20px