Not totally sure, but not convinced it could be anything else, for this area. I think it is the unconventional flight posture (wanting to land but intimidated by another blue heron on the bank) and the early morning lighting that makes it look unusual.
Maybe some ornithologists on UHH here can chime in.
Thanks. To tell the truth I hesitated to post it, since it is a pretty extreme crop, he was high up there! Love my Canon 100-400 II zoom with a 1.4x TC. It is a fine lens.