Richard,
I've never been to Ding Darling but from what I hear, it's a great place to shoot migratory birds. Temps now are in the high 70s to low 80s. I'm getting Herons, Ibis and Sand Hill Cranes in the back yard so I'm betting the selection over on the West Coast at Sanibel will be amazing.

Good luck and while you're there, I'll be in Colorado looking for some mountains to shoot. Let's exchange image posts when we get back home.

Jim