Oly has a new toy for us long lens photographers.
http://www.getolympus.com/us/en/accessories/ee-1-dot-sight.html
They've borrowed from the gun world and designed a red dot scope for photographic use. It's difficult to keep a moving object in frame when using a long telephoto (4x or more) and damn near impossible with supertele lenses (10x and more). The new device slips into the shoe and, once adjusted (sighted in) allows the photographer to see the entire field of view instead of looking through the straw that is a long lens.
I know from personal experience that shooting (pardon the pun) birds on the wing with 1,200mm (24x) equivalent is frustrating at best. While you won't be able to compose you'll at least get the subject in-frame and in focus.
Now, if you're as cheap as I am, you may want to construct one yourself. Oly wants $130 for theirs and mine cost less than a third of that. PM me for a parts list and instructions but be patient as I'm leaving town for awhile and will be dealing with hotel "high speed internet".