Joe, my recollection from other posts is that your preferred procedure for BIF is to set the shutter speed and aperture manually and then shoot with auto ISO, and make any necessary exposure adjustments by changing the exposure compensation so that you have no blinkies on the LCD display. Unfortunately for me, this is one area where Nikon cameras have the edge over Canon since with Canon there is no exposure compensation when shooting in manual mode with auto ISO.
This got me thinking about options for Canon owners. One long-standing trick when a gray card is not available is to take an exposure reading off green grass or other similar green vegetation. Fortuitously, green grass is much the same as an 18% neutral gray card.
Next time I'm shooting a bird with white (or black) feathers I'm going to try to be disciplined to take a probably spot meter reading off some nearby grass as long as it is in the same level of light as the subject of the photograph. I googled this and found at least one other person who agrees with me:
http://www.dpreview.com/forums/post/51690502 . Finding green grass is a bit of a challenge at this time of the year in my area but many other types of green vegetation (not conifers) can serve the purpose.
This exposure reading can then be varied up or down depending on whether the feathers are white or black (or should this be black or white?
). It seems to me that this would provide a good starting point for Canon photographers for an initial shot. If there's time, the blinkies can be checked; if not, hopefully you have an image that is somewhere in the ballpark.
Another option might be once the initial exposure has been identified to then take bracketed exposure shots (the scattergun approach to photography). I don't know how this works with Nikon cameras but with my Canon, if I set it to high-speed shooting and set the amount of exposure bracketing, the camera will take three photos in immediate succession when I press the shutter button once. I did a test this afternoon to see what adjustment the camera was making in order to change the exposure. It varied the shutter speed and left the aperture and ISO unchanged.
What does everyone think?