Presidio of San Francisco Live Cam - Great Horned Owl Nest

Last year, over 200,000 viewers watched via​​ live webcam as a pair of Presidio Red-tailed Hawks successfully reared two chicks high up in a Presidio eucalyptus tree. This year, we have an unexpected plot twist: a pair of Great Horned Owls have taken over the nest, and they recently laid two eggs of their own.

The situation is not uncommon – it reflects the way animals in the wild often rely on each other for survival. In this case, Great Horned Owls do not build their own nests; rather, they take over the nests of other raptors.

In early February 2019, the owls stopped by at night to inspect the Red-tailed Hawks' nest while during the day the hawks, unaware of the nightly owl visits, continued to prep the nest for the season. At one point, there was a brief confrontation between the owls and the hawks where it appeared the hawks maintained the nest. But then during the early hours of February 5, the owls laid an egg in the nest, and on February 9 they laid a second egg.

Update: During the heavy storms of late February one of the eggs was cracked. The mother ate the egg as it was no longer viable. The resources of that egg, such as the calcium from the shell, are essential for owls and hard to come by so they were "recycled" by the mom.

The incubation period for a Great Horned Owl egg is about 30-37 days, and the egg was expected to hatch around the first several weeks of March. At this point, the egg has missed its hatching date and our wildlife ecologists don't think this egg is viable. This is not unusual - often eggs do not hatch and it doesn't indicate that this pair will not have a successful brood in the future.

At this point, this momma may continue to try to incubate this egg for a week or two, but will eventually move on and may return to the nest next year during nesting season...or this nest may be occupied again by the Red-tailed Hawk pair!

Thank you for tuning in and hope you continue to enjoy learning more about this active nest.

​Photo Credit: David Assman, Charity Vargas

Видео Presidio of San Francisco Live Cam - Great Horned Owl Nest канала presidioSF