Please note that this information is only noted from the world of Vesta and is filtered through the perceptions of Keensight.
Dragon habitats are as varied as there are dragons. Most people just assume that they have a cave and often this is the case. However, there are definitely some preferences and variations. Like people, not all dragons want raise their fledglings in the same environments. Of course, exploration of these habitats are dangerous and therefore most of what we know are from abandoned nests.
Black Dragons are slightly more wiry than their larger cousins. Due to this, they often find holes in the ground that cannot be really classified as caves. However, they have no qualms in taking over an abandoned cave. They prefer dark recesses where they can blend in and their spaces are often tighter then many of their kin.
Blue Dragons usually find natural caves that can be reached from underwater but have an air space within. They often will also choose sea side caves hard to reach due to the tides and crashing water. They prefer wet caverns as they often incubate their eggs in warmed water.
Bronze Dragons almost always dig their own caverns and these are as varied as the dragon. They may have winding corridors to their nest, organized rooms or even one large cathedral like space.
Green Dragons do not like caves at all. They will usually choose natural crevices that are hard to reach except by flight but never one with a roof. They do not mind the rain and will migrate to avoid the snows. They are most comfortable in mossy and heavily wooded areas.
Gold Dragon - Unknown at this time. No known nest or cave has been found.
Red Dragons are your typical dragon. They like caves and often have them close to areas of natural warmth. They tend to live in areas without snow. However, if the cave is deep enough to maintain a year around tempature, they have been found that far north.
Silver Dragons like to take over fallen cities, old castles and other such shrines. They redecorate making their nest an area of beauty, serenity and peace. They can also be found behind waterfalls if the area behind is dry enough.
White Dragons prefer sea facing caves hollowed out from icebergs or glaciers. Their caves are made by their own efforts and are often marvels of sparkling ice and sculpture. Rare is the ice dragon that has not created an ice scape that draws the eyes. This can be dangerous if you are staring at their surroundings if they are hungry.