Wow! Some real stella shots in this thread! While I feel my own bird photography has greatly improved since I first began back in September 2010, BIF captures that I'm happy with remain few and far between for all my efforts. Still, if it was too easy where would be the fun it that, right? 
Although the silhouettes are not quite as sharp as I'd have liked them to be, this is probably the first image I captured of birds in flight that I still like to this day. It was taken on my first trip to Sabah (Malaysian Borneo) back in November 2010 and, as luck would have it, it was to be the only colourful sky I witnessed close to sunset during the 12 days I was there.
My guide and I had been drifting silently along one of the tributaries off the main Kinabatangan River one afternoon in our low-lying boat, watching both Wrinkled and Rhinoceros Hornbills feeding off figs in the trees along the riverbanks. As the sun began to make it's descent I began praying for Mother Nature to finally whip out Her paintbox and go crazy with the sky. With evidence that Mother Nature was feeling in a benevolent mood, I pushed my luck still further and pleaded with her to entice a Hornbill to fly from one side of the river to the other, so I could try and capture an in-flight silhouette ... no doubt with a glint in Her eye, not only did she send one, but two Rhinoceros Hornbills across!!! 
As suggested above, this is far from perfect IMO, but I love it all the same, for the memories that comes flooding back each time I look at it reminding me of that perfect moment with Mother Nature! 
Shooting Data: Canon EOS 7D, EF 70-200mm f/2.8L IS USM MK II @ 70mm, Aperture Priority @ f/2.8 (1/125 sec), 0 EV, ISO 100, Handheld, JPEG from RAW, About 80% of Full Frame
P.S. When looking at the techs above, it'll no doubt be immediately apparent to any of you more seasoned photographers that I could have created a far better shot with different settings, and with barely a month's experience under my belt at the time, getting this shot to come out as well as I feel it did was much more down to luck than any notable skill on my part; perhaps this was a third gift that Mother Nature blessed me with that afternoon 
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