When Great Horned Owl eggs hatch, the downy owlets are the size of newborn chickens. Their mother broods them day and night. A few weeks later, the owlets can be left alone while both adults resume hunting at twilight. Great Horned Owl young remain in the nest for about six weeks, then climb out onto nearby branches. They begin taking short flights at seven weeks, and can fly well at 9-10 weeks.