The largest North American heron. In the East, its ecological niche is occupied by the grey heron, which is extremely similar in appearance. They can be differentiated in that the great blue heron has rusty-gray neck with black and white streaking down the front. The grey heron lacks this streaking.
Otherwise, this heron has slate blue-grey flight feathers, red-brown thighs, and a paired red-brown and black stripe up the flanks; the head is paler than the neck, with a nearly white face, and a pair of black or slate plumes running dramatically from the eyebrows all the way to the back of the head. The feathers on the lower neck are long and plume-like; it also has plumes on the lower back at the start of the breeding season. The bill is dull yellowish to orange, and the lower legs are gray to orange (depending on season).
Do not confuse with grey heron (see first paragraph).
