I'm not sure specifically what the 'old eagle story' is about without more context. It could be a story about an old eagle's adventures, its life cycle, or perhaps a fable with a moral lesson involving an old eagle.
The 'old eagle story' could cover a wide range of topics. It could be a narrative about an old eagle's relationship with other animals in its habitat. For instance, it might have a special bond with a particular species or be in competition with others. It could also be about the physical and mental changes that the old eagle experiences as it ages. In some versions, it might tell of how the old eagle imparts its knowledge to younger eagles. Maybe it shows the old eagle teaching the young ones how to build nests more effectively or how to sense approaching storms. There could be elements of courage in the story as well, like the old eagle facing new threats that it didn't have to deal with when it was younger.