Actually Jim, I used Matrix metering and underexposed, which is the complete reverse of what the pros tell you to do. This because a bird in flight is almost impossible to spot meter correctly. The dark background was three years in the planning. I had visited this same roosting site for three years in a row and I knew exactly what I wanted. That last time it all came together. Then someone decided to cut the background trees down so now that shot is no longer possible.
The birds fly back and forth to their nesting site, gathering twigs and such. I positioned myself where I had a tall stand of thick Australian pines as a background and waited for late afternoon golden light to backlight the birds. The sides of the trees facing the camera were in very deep shade and completely blurred by the long lens and wide open aperture. I set my exposure and just waited. The rest is history. That image now hangs on a number of walls

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I have used that technique many times for birds. Here's another one, but with front light - the reflection of the big pine trees makes the water look completely dark. This one was on the cover of the Where Guestbooks - Tampa Bay issue a few years back.
Best,
Jose