I was down near a creek bed in the dense forest in Northwestern WA., so there wasn't much sunlight getting down there.
I was shooting handheld in manual. So at 300mm with IS, the lowest shutter speed that worked was 1/125. At then long end, that lens starts being sharpest at f6.3. So with the ISO on auto, 4000 is what it took to get the exposure. The image did not need to be cropped, so that helped a lot.
I have a couple at ISO 1600, when I had the ISO on manual and they were coming out underexposed and had much more noise. So I just let the camera figure it out. The little light there was, was pretty even. So the camera did a good job.