All of the banners and many of the photos were provided by Greg Lavaty. His work in Costa Rica (and elsewhere) is always stunning. He has been enormously generous.
Other photographers that I use regularly include Annika Lindqvist, Bruce Hallett, Juan Diego Vargas, Johan Chaves, and Lora Render. I take all the uncredited photos, usually of locations, since I'm too embarrassed to put my bird images next to these people.