Generally speaking, the dragonscape is a lot more feral than the Americas that it once was 3000 years ago and that is seen in the food sources of the drekir.

Most sedentary villages live a mix of hunter-gatherer and agricultural lifestyles, both farming and relying on natural food sources to sustain themselves. Fishing, gathering, foraging, hunting, and farming all together to keep themselves well fed.
Much of a drek's life is getting food for themselves, their denmates, and their wider village and there are hundreds of different ways of doing it. Drekir in Washington hunt differently from those in Brasilia for example, and some drekir cultures might only fish, others may only hunt, some may do both. Things vary wildly based on the regional situation

as for agriculture
In the 3000 years before the drekir awakening, once bountiful crops would grow more feral and undomesticated, think pre domestic corn vs. modern corn crops. Additionally once domestic animals have long gone feral and some time and effort is needed to reacquaint these now draconic creatures to the concept of domestication.
Agriculture is possible, though can't solely be relied on.