Thanks for all the comments guys. BTW, these were all hand held. I did notice the increase in weight over my 200-600mm a bit while carrying for an hour, but shooting felt similar. I'm going to try a monopod next time.
Louie, I couldn't believe that I'd never driven over there! I always headed further north, but finally decided to go somewhere new. My wife and I really enjoyed the longer walk on a nice path, and there is plenty of parking. Now I want to return at high tide to see what it looks like. This will certainly become one of my go to birding spots since it is closer to our house in Lake Stevens.