Unlike most owls, Snowy owls are diurnal, which means they are active during the day and sleep at night. Females are larger and heavier than males, as is true for many bird of prey species. Snowy Owls which are mainly white are always males (just like the one that played Hedwig in the Harry Potter movies). Females tend to be more heavily barred. Their white plumage acts as camouflage against the snow. Snowy owls are solitary when not breeding and very territorial. They will fiercely defend their nest (which is built on the ground), from predators. They are migratory but difficult to predict as they seem to migrate only when food becomes scarce.
Monogamous (one male breeds with one female) however, if food is plentiful two females will breed with one male. Males preform aerial display to attract females. Breeding takes place between May and September. Females will lay one egg every other day up from 3-11 eggs and incubate from the first egg laid. Chicks in a nest are always different ages and different sizes.
Snowy Owls are endangered or threatened across the US, but are protected under the US Migratory Bird Act.