Great horned owls do not construct nests but customarily usurp the nests of other large raptors. Hollow trees are occasionally used and in mountainous or desert terrain, where trees are sparse, they will nest on cliff ledges and promontories and sometimes even on the ground. Pairs typically mate for life, share in the defense of territory and usually occupy the same territory for several years. They are very early nesters, even here in the Interior egg-laying and incubation can be well under way by March. Nesting occurs earliest during years of peak snowshoe hare populations and the number of eggs laid will be greater in years of hare abundance.
Incubation takes about a month and the young owls are capable of short flights around eight weeks.
Both parents take part in feeding the young. Scientists suggest the early nesting maximizes the time for developing hunting skills before the next winter. The young are dependent on the parents throughout the summer for food and do not disperse from their natal areas until fall. About 50 percent of the young which leave the nest die within their first year from various causes. Fortunately, the great horned owl remains so widely distributed and remarkably tolerant of major habitat disturbance by man that its future seems secure for now.