Hi Sven,
The trail to Little Harbor is good for buffalo. It's a bit of a long one though. You know that old buffalo named Wilson can often be seen at Cat Harbor and even at Two Harbors at times. I have seen him at both places. On the hike to Little Harbor you will gain elevation quickly and get some nice vistas, then you will go down into the Little Harbor camp ground and of course you will have to hike up to get back out. It's pretty much a full days hike round trip.
If you looking for a easy level hike with a constant view of the shore you can take the trail to Emerald Bay. For the most part pretty level. There is also a nice trail that connects the trail to Emerald with the trail to Silver Peak above Cat Harbor. It get's really steep. Keep an eye out for Rattle Snakes. I have not yet seen one on Catalina, but I know they got em. I try to avoid the tall grass where I can't see my feet. I have also done some off trail bush whacking in that area but It's probably frowned on.
As far as the Eagles are concerned, I have only seen them at Two Harbors, flying right over the moorings at times.
Just ask at the Information Office right at the end of the Pier. They know a lot more than I.
Here's one of my Wilson encounters.
http://www.youtube.com/user/jazapuss#p/u/10/JxQqKrGnG20