I spent about 20 minutes waiting for this Great Blue Heron to catch a fish or fly away so that I could get an action shot with those big wings spread. He did neither.
The most exertion he managed was to bend over occasionally and take a close look into the water for fish or to admire his reflection; it was hard to tell:
It was a warm day by Maine standards, but this bird didn’t appear to be uncomfortably hot, a state that you often can detect in Great Blues, our largest native wading birds. They principally show heat stress in two ways. First, they’ll stand with their wings down and out to allow cooling air to flow over themselves better.
Second, and more interesting, GBHs and some other birds will keep their beaks open and look like they’re gasping. That’s called “gular fluttering” because it involves quivering the gular (throat) muscle to help to carry heat out of the body quickly through lungs and air sacs, while bringing in cool air to regulate body temperature. Think of it as bird panting.
(Images taken in Brooklin, Maine, on August 20, 2023.)