Great shot. I've always loved when they do that pose, though I didn't really know the meaning behind it...whether it was a mating thing, or a warming up thing...or just comfortable. I always referred to it as the 'satellite dish' pose. Once caught a yellow-crowned night heron doing that pose while walking around on the boardwalk...he stayed in that strange pose even as he walked away from me, like some kind of DeNiro attitude pose:
I believe it is actually absorbing vitamin C from the sun. I have seen cormorants and great blue herons do it also as I am sure you have
Thoughts I've heard around from some birders was that it might be to warm up the feathers and discourage parasites from digging in, and moving on to another location - in effect loosening them up to be more easily picked or preened away. I know the cormorants and anhingas need to dry off their feathers after a swim, but they are usually with their backs to the sun - the herons and egrets seem to perform this satellite-dish pose facing directly into the sun, and often perform cooling exercises with their gular fluttering (at least down here in the hot Florida sun!)...almost as if they're heating themselves up a little too much, and cooling themselves while doing it - which would make me think it could be a maintenance thing they feel they must occasionally do. I suppose lapping up vitamins from the sun is also feasible!
they do the gull fluttering thing here also I thought the cormrorants were drying off but I see them dive for fish and then fly away soaking wet. I will have to google this
