I’m not sure what this bird posture means. He could be saying, “I dare you to come closer, so I can eat you.” He may be saying, “I would leave if I were you, because this is MY tree!”
He may just be stressed because he is molting. He was flinging feathers with his bill in every direction.
Red-winged Blackbirds like to flash their colorful wing patch and loudly sing to defend their territory. They cover the wing patch when they enter another Red-winged Blackbird’s territory. This may be the most abundant bird in North America.
The male Mallard is keeping a low profile and enjoying a lazy Sunday afternoon. He has his nonbreeding plumage. He is still recognizable with the white bordered blue patch on his wing.