Hummingbirds chase each other primarily to defend territory , which includes securing feeding grounds with nectar and protecting breeding and nesting sites. Males often chase rivals to assert dominance and attract mates, while females chase others away to protect their nests. The chases and aggressive behaviors serve to establish and maintain control over valuable resources necessary for survival and reproduction. These territorial disputes can involve high-speed aerial displays, vocal warnings, and sometimes physical confrontations, especially during mating season or when defending limited nectar sources like flowers or feeders.