The gulls and the gadwalls took off into the air. The gulls were faster at getting airborne than the heaver gadwalls. You can see the spillway of water down the side of the dam in the background. What you don't see here is that the coots were still running on the ground, much slower. Which may explain why they end up eagle prey often.
Ring Billed Gull (Larus delawarensis)
Gadwall (Anas strepera)