The Great-horned Owl (Bubo virginianus) is a year-round resident of western Montana and highly territorial. They live in a wide variety of habitats but prefer open and secondary-growth woodlands containing open fields for them to hunt in.
This Great-horned Owl has chosen a territory that includes an open area so it can fly back and forth across the break, swooping down on its prey in the open area. Males protect their territory mainly through “hooting” but have been known to kill other Greathorned Owls within their territory. This owl has many rods in its large eyes and very large pupils that allow it to see quite well at night, however its eyes do not actually move. Also, owls cannot spin their head around 360 degrees as it sometimes appears. They do have great flexibility in their neck joints that allow them to turn their heads greater than 180 degrees, and as they swivel their body and shoulders it appears as if their head is spinning all the way around. This motion also allows the owl to hear in many different directions. They have acute hearing and large facial disks and feathers that direct the sound to their ears.
Once paired, the male Great-horned Owl will allow the female mating partner to roost within his territory in a nearby tree. They are apparently monogamous and may mate with the same female for up to five years. They are often heard hooting back and forth to each other. Great-horned Owls do not participate in any form of nest-building. They commonly use old Red-tailed Hawk (Buteo jamaicensis) nests or may nest in large tree cavities. They do not add to or maintain the nest through brooding and the structure has been known to fall apart and show great signs of wear. They generally lay one clutch per season from February through April of approximately 1-4 eggs. The eggs are incubated by the female only for 30-37 days, with the male feeding her throughout the night. The young begin moving from the nest at 6 weeks of age but don’t attempt any flights until 7 weeks. The fledglings will stay with their parents for the entire summer and disperse throughout the autumn and winter.
Listen for the Owl in this audio clip:
The photograph to the left was taken at the base of a roosting tree and shows two owl pellets. Approximately 13 hours after eating its prey, the Great -horned Owl will regurgitate the bones and fur in the form of owl pellets.