Photos and VideoGreat Horned Owl Nest, Spring 2012
Treetop photos & videos March 23 – May 15, 2012
A few weeks after the second owlet fledged, we removed the cameras from the tree adjacent to the nest. We've highlighted the entire process in the following slideshows and video accessible via the links below. These pages tell the amazing story of one great horned owl family from incubation through fledge. Maternal patience, sibling rivalry and baby's first "flaps" are only a few of the highlights. Sit back, click, and enjoy!
Questions? We'd love to hear your feedback. Feel free to post comments and questions on our Facebook page, or send them directly to Allison F.
Video from the base of the tree March 23 – May 16, 2012
An eastern gray squirrel is making its daily rounds. Gray squirrels are “scatter hoarders,” burying one nut at a time in areas up to seven acres in size. Mature gray squirrels eat as much as two pounds of nuts each week and hoard thousands of nuts per year.
BackgroundDid you enjoy the motion-detection photos from our predator monitoring project? We are hoping to put those same cameras to good use when they aren't helping us count carnivores. These special infrared cameras are able to record wildlife acting naturally, reducing the stress that flash photography can cause. Moving forward, these cameras will change locations, recording various wildlife.
Great Horned Owl Nest, 2012
Cameras installed February–March, 2012
A great horned owl nest was discovered by District staff in early February, when two owls were heard hooting back and forth at Wright Woods (Mettawa). One owl flew away in a presumed attempt at distraction. The female was then spotted peeking out of a nest located in a nearby tree.
Great horned owl vocalization:
In late March, the forestry crew set up two cameras in an adjacent tree. Four cameras were also placed at ground level, in hopes of capturing the fledgling owlets and other wildlife in this area.
The height of the nest is estimated at 85 feet, judging by the length of rope required to climb the tree. The nest itself was likely built last year by a red-tailed hawk. Great horned owls don't build their own nest—instead, they choose an old nest or a large cavity that meets their needs.
Owlets hatch! March, 2012
Owlets were visible through a viewing scope for the first time on April 5. Photos and video from the cameras placed in an adjacent tree suggest that the first owlet hatched on March 28. The second owlet hatched about two weeks later on April 11. In many of the photos, one owlet is twice the size of the other—the one that hatched first also fledged the nest one week earlier than the second owlet. Great horned owl eggs rarely hatch at the same time and developmental variance is very common.
“Tree cams” removed
The cameras that were placed 85 feet above the ground were equipped with large memory cards and plenty of batteries. To avoid stress on the owls, these cameras remained in place until both owlets fledged. Once the owlets left the nest, we waited a few weeks before climbing up to remove the cameras. Upon initial inspection, there were over 5,000 photos and 2,000 videos! We then knew an exciting story of an owl family was available to share. Though cameras at ground level did not pick up any owl adventures, they did provide fun glimpses into the daily lives of local wildlife.
Species InfoGreat horned owl, Bubo virginianus
Description Great horned owl (GHOW) vary in color from brown to gray, with a wingspan of three–five feet. Their name is derived from the tufts of feathers on either side of their head. GHOW have excellent hearing and sharp vision. Their eyes are incapable of rotation; instead, they are able to rotate their heads 270 degrees in a fluid motion. GHOW activity begins at dusk. GHOW may aggressively protect their nest from threats.
Mating rituals Males and females hoot to each other during nesting season, January–February. They are the first bird species to nest in Lake County each year. Although nearly identical in appearance, the male uses a distinctive posture while calling. The male calls from a prominent branch, holding his body horizontally, drooping his wings, cocking his tail slightly, and inflating his white throat patch. Mutual bill rubbing and preening has been noted when the pair is together. The GHOW pair maintain the same territory for up to eight years, remaining solitary during most of the year, staying with their mate only during the nesting season. The average home range is one square mile.
Nesting habits GHOW do not build a nest of their own, instead they occupy a nest previously built by other large birds, such as red-tailed hawks, American crows and great blue herons. GHOW may also use hollows in trees, clumps of witch's broom, rocky crevices, or artificial platforms. The addition of a few feathers is the only modification the female makes.
Two–four eggs are typically laid. The female sits on the nest constantly during incubation, about 26–35 days. The male perches nearby during this period, bringing food to the female. As the owlets grow the female spends less time on the nest but perches nearby to defend it if threatened.
Owlets The owlets are dependent upon their parents for food until the fall, and their harsh begging calls can be heard throughout the summer. They begin roaming from the nest onto nearby branches six–seven weeks after hatching, and cannot fly well until 10–12 weeks of age. Juveniles disperse up to 150 miles from the nest site in the autumn, while adults tend to remain in their breeding areas year-round.