The new generation of image-stabilized cameras is extraordinary at some things. Here's a Green-and-rufous Kingfisher, taken offhand from a moving boat.
This is hand-held 1/160sec from a rocking rowboat with an outboard motor, at 12x zoom. I grabbed three "what-the-hell" shots, and two were certainly good enough for bird ID help.
It's not just distant wildlife; here's a tiny drop of latex from a rubber tree. I didn't want to be obnoxious about the camera or crowd the others, so I stood well behind the others and zoomed in: height does have advantages. The problem is that the rainforest is (by definition) not very bright, so this is 12x and 1/40sec.
Not art, but surprisingly good for a run-of-the-mill consumer camera (a Canon S3).
You never know who you'll meet on the trail: