I obtained this image at Artie's JBNWR-Nickerson IPT. I missed out when the gull first grabbed the young skimmer but got it holding the head and pulling the entrails out
D300s Sigma 50-500 @ 500 mm hand held ISO 800 1.320 sec @ f 8. PP in PS
Totally gruesome.... but I guess it's just nature at its wildest. Looks like you had a challenge on your hands getting a balanced exposure. I also like the pano crop. Perhaps a tweak to brighten up the shadows just a little.