Just back from an Ecuador Birding expedition, that took me to the Amazon (Napo River), Quito, Western Cloud Forest, and high-altitude, Paramo areas. 400+ bird species in two weeks, is a lot of good birding.
One thing I noticed with my trusty D90 and 70-300mm was the extreme darkness of the forest floor, especially with clouds and rain (they do call it a rain forest!). Also, the filtered light was extremely green, which made me aware of my inexperience with WB settings. While the forests were dark, any view of the sky blew out the highlights, so I had to ride the Exposure compensation A LOT, making frequent use of EV -.7, -1.3 or -2.0.
I felt the Nikon matrix exposure was a lot less dependable than normal, and I had to do a lot of chimping to avoid blowing out the highlights.
Red flowers are a major pain, as any reflection gives excessive highlights. Bright white or yellow bird feathers are also easy to blow out.
I found that a polarizer was essential for dealing with reflections from shiny, wet leaves.
I also feel that my photography technique needs to include more use of manual settings. Maybe all you old film guys are good at guessing the light, but these new digital cameras adjust three ways: ISO, Aperture and Shutter, which means too many degrees of freedom to memorize. I tend to use Aperture Priority for the most part, but I was constantly riding the ISO and Shutter speeds. I made extensive use of ISO 800 and even 1200, trying to balance between blur and sensor noise. My 50mm 1.4 came in handy, but for wildlife I really could have used a BIG-mm f/2.8... not that I wanted to carry one.
I'd appreciate any comments on dealing with forest floor issues.
Technicolor Toucan, Mindo, Ecuador: