Since 2007, I banded 64 Golden-crowned Kinglets in Minnesota. None showed aggression like this male last Sunday. When alarmed by predators or male intruders, Golden-crowned Kinglets erect their crown feathers. This action also indicates agonistic behavior, when a male invades neighboring territories. Combatants expose their crown patches and bow their heads towards opponents (Swanson et al. 2012). Unlike birds in the previous examples, my bird remained silent during our interaction.