What is a young raptor that cannot fly yet called?

A young raptor that cannot fly yet is referred to as an eyas. This term is specifically used to describe a nestling or juvenile bird of prey that is still dependent on its parents and has not developed the ability to fly. In the context of raptors, the term nestling generally refers to all young birds that are still in the nest, including those that have not yet fledged.

Thus, both terms—eyas and nestling—accurately describe young raptors at this stage of their development. The correct answer encompasses the understanding that both terms are related and applicable to the same stage of a raptor's life cycle. While the term "passage" refers to raptors that have fledged but are still considered young and not yet established in their adult roles, it does not apply to the stage before they can fly. Therefore, the answer captures the essence of the terminology used within falconry and bird conservation, highlighting the relationship between these terms within the context of a young raptor's life.