OK, let's face it, Coots don't look like they always have both oars in the water, but I have gained a new level of respect for them. I witnessed an Eagle attacking a raft of Coots, and their defensive mechanism worked quite well.  They splash up so much water that the Eagle can no longer see them.  I watched the Eagle make 20 or more passes, and he never succeeded in getting a grasp on a Coot.  

I watched this drama for about 20 minutes.  During that time the Eagle had to take several breaks because he was getting so exhausted.  About one hour later, I was in a different part of Juanita Park when the Eagle flew in with a Coot in the talons.  So, likely the Eagle attacks the raft of Coots enough times to finally exhaust the Coots as well.  Whoever has the most stamina wins.