The Red-Winged Blackbird can be very aggressive while defending its territory from other animals and birds. It will attack much larger birds, such as crows, ravens, magpies, birds of prey and herons if they enter. Only on a very few documented occasions have they been known to attack humans who encroach upon their territories during mating.
Even when I am on the lookout for them, one of them will scare the heck out of me on a typical walk. Never seen them strike Elo or myself, and they tend to swoop in from the rear as we depart their territory, so it seems to be more of a show than anything. However, I did see one chasing, harassing, and driving off a hawk a week or so ago.