The birds aggressively defend their nests and surrounding areas against other birds and animals. When a predator is persistent, mockingbirds from neighboring territories may be summoned by distinct calls to join the defense. Other birds may gather to watch as the mockingbirds drive away the intruder. In addition to harassing domestic cats and dogs that they consider a threat, mockingbirds will at times target humans. The birds are bold, and will attack much larger birds, even hawks.
Like other columbines, the mourning dove drinks by suction, without lifting or tilting its head. It often gathers at drinking spots around dawn and dusk.
Mourning doves eat almost exclusively seeds, which make up more than 99% of their diet. Rarely, they will eat snails or insects. Mourning doves generally eat enough to fill their crops and then fly away to digest while resting. They often swallow grit such as fine gravel or sand to assist with digestion. The species usually forages on the ground, walking but not hopping. At bird feeders, mourning doves are attracted to one of the largest ranges of seed types of any North American bird, with a preference for rapeseed, corn, millet, safflower, and sunflower seeds.