Interestingly, I didn't feel at all threatened, not in the slightest. Maybe it was a mutual curiosity, although I'd worked a bit with eagles after that (while volunteering at a Raptor rescue/rehab place) and didn't find them particularly curious; OTOH, it's not exactly a natural setting. Either way, it was almost like an invitation - as though, when i lost my "zen" or whatever, started thinking fearfully, the bird got the notion of "meeting me halfway".
Tangelntailly, I remember going with someone to nab an injured bird in a wooded area (this was while I lived in British COlumbia, immediately south of Vancouver, BC), and ther eweer a number of Bald Eagles in the trees. THey eyeballed us, but didn't seem particularly afraid. More wisely-cautious than afraid (which makes sense - I'm cautious of poeple, too).
Mysterious creatures. I have no patience whatsoever for those people who claim that "animals are merely biological robots"; they of course aren't "people with fur or feathers", but they do have their own thought processes, just not *verbal* thought processes - which makes sense to me, since I tend to think visually (and then "translate" it all into language to relay it to other people). ANYHOO, to this day, I can only specualte why the bird would have flow *towards* me, because form a sceintific/biological viewpoint, it made no sense whatsoever. Which give it an almost "mystical" sort of quality. But in any event, it was very cool :)