For the past several seasons, a pair of great horned owls (Bubo virginianus) has been reliably resident in the eucalyptus trees of Forest Knolls' upper streets. Residents who walk at dusk and dawn will be familiar with their deep, resonant five-note hooting — one of the more distinctive sounds of the neighborhood.
Great horned owls are the largest common owl in North America, with a wingspan that can reach up to five feet. They are apex predators of the urban forest, capable of taking prey as large as skunks, rabbits, and — notably — other raptors and birds of prey. They have been known to displace red-tailed hawks from nesting territory.
Nesting behavior
Great horned owls are among the earliest nesters in North America, often beginning to incubate eggs in January or February, when temperatures are still cold. They don't build their own nests, instead appropriating those of other large birds — hawks, ravens, or herons — or using natural cavities in large trees. The female incubates while the male hunts and delivers food.
By March or April, fledglings can be heard calling from the eucalyptus canopy — a raspy, persistent begging call very different from the adult's hoot. By midsummer, the young owls are typically dispersing from their natal territory.
How to find them
- Listen at dusk and dawn — that's when they are most vocally active. The male's hoot is lower-pitched; the female's slightly higher.
- Look for large, bulky silhouettes in the upper canopy of the eucalyptus trees along the upper neighborhood streets and the forest edge.
- In winter, look for "whitewash" (droppings) and pellets on the ground below favored roost trees — a reliable sign that owls are present overhead.
- During breeding season, mobbing behavior by crows or jays — lots of harsh calling directed at a particular tree — often reveals a roosting owl.
Please do not use bright lights or make sudden noises near a roosting or nesting owl. Disturbance during incubation can cause the adults to abandon eggs or chicks.
To share sightings, post to the neighborhood blog or report on eBird to contribute to citizen science records for the area.