The California Spotted Owl

From left: northern, California and Mexican spotted owls. USFWS photos by John and Karen Hollingsworth, Rick Kuyper and Shaula Hedwall.

The spotted owl is usually pictured in the damp, dark forests of the Pacific Northwest. In fact this old-growth forest bird comes in three subspecies spread across the western United States:

This profile, from the National Park Service's Klamath Inventory and Monitoring Network, focuses on the California spotted owl.

What it looks like

All three are medium-sized owls (46–48 cm, 18–19 in), chestnut to dark brown with white spots or blotches over much of the body. White and light brown bands cross the wing and tail feathers. The round face is a disk that gathers sound, with a whitish "X" of feathers around a yellow-green bill.

Two features set spotted owls apart from most other owls: dark brown eyes (most owls' eyes are yellow) and no ear tufts.

Telling the subspecies apart is harder, though their ranges overlap only in northern California. In general the California spotted owl sits in between: smaller and paler than the northern, larger and darker than the Mexican.

Its close relative and competitor, the barred owl (Strix varia), is slightly larger and has dark vertical streaks on its belly rather than white spots, horizontal bars across the breast, a brighter yellow-orange bill and a different call.

Habitat

Like its cousins, the California spotted owl nests in dense, shady forest with large old trees and fallen logs:

• Big trees offer cavities, heavy limbs and broken tops for roosting and nesting.
• A shady, many-layered canopy hides the nest and keeps the owl cool.
• Wood on the forest floor shelters woodrats and other prey and grows the fungus rodents like to eat.

It hunts in this mature forest but also in more open ground, near edges and clearings that hold a wider range of food. Spotted owls generally don't migrate, but California spotted owls may move in winter from nesting areas in mid-elevation conifer forest down to lower places such as the foothill streamside and oak woodlands of the Sierra Nevada.

A silent hunter

An owl's feathers are built for silent flight. Comb-like serrations on the leading edge of each wing feather break up the turbulent air that makes the swoosh of flight; a velvety surface layer muffles it further; and a soft fringe on the trailing edge lets the air slip away quietly. Add sharp eyes and keen hearing — the facial disk funnels sound into offset ear openings, which pinpoint the faint rustle of prey — and the owl is well equipped.

The California spotted owl hunts at night, mostly for flying squirrels and woodrats, but also mice, pocket gophers, birds (screech owls included), lizards and insects such as moths. It makes short flights from a perch to catch prey on the ground or in the canopy, swallows it whole, and coughs up the bones and fur as a pellet. Extra food is stored on mossy limbs, broken stumps, under logs, in tree hollows or among mossy rocks.

Spotted owls, especially their eggs and young, are themselves eaten by great horned owls (Bubo virginianus), common ravens (Corvus corax) and American goshawks (Accipiter atricapillus).

Behavior and breeding

Outside the breeding season spotted owls live alone, though they usually share a home range with a long-term mate. In spring, pairs come together: they perch side by side and preen each other's face, head and neck feathers (allopreening) with soft cooing and chittering. Nesting season also makes them fiercely territorial, and they answer other owls' calls — real or imitated by people — aggressively. In flight they alternate short glides with quick wingbeats, their large wings for their size letting them weave through the trees after prey.

A fledgling California spotted owl. USFWS / Rick Kuyper.

• Mid-February: pairs begin roosting together and courting; the male brings food as gifts, and the pair call to each other at dusk and dawn.
• Nest: like most owls, it builds none. It may take over an old raptor nest but usually lays its 1–4 white to pearl-gray eggs in a broken top or cavity of a big old tree. In the Sierra Nevada, nest trees average 124 cm (49 in) across at breast height and 31 m (103 ft) tall, and one study put the average age of nest trees in the southern Sierra at more than 227 years.
• Hatching: the female incubates for about a month. The downy, helpless young stay in the nest about 5 more weeks.
• Branchers: nestlings often leave early to hop along nearby limbs, flapping hard as they learn to fly.
• Leaving home: fledglings stay with their parents through the summer, then disperse to find a mate and territory.

Conservation

A California spotted owl "in questioning mood," Yosemite National Park, 1934. Joseph Dixon, public domain.

The northern spotted owl was listed as threatened under the Endangered Species Act in 1990 and the Mexican spotted owl in 1993. The California spotted owl was proposed for listing only in 2023, with separate recommendations for its two Distinct Population Segments: threatened for the Sierra Nevada population and endangered for the Southern-Coastal population.

Its threats:

• Past logging of mature forest removed nest trees, canopy cover and fallen logs.
• Large, high-severity wildfires are increasingly destroying nesting and foraging habitat.
• The invasive barred owl — larger and more aggressive — competes with it and can hybridize with it as it spreads south into California.

Where to see one

California spotted owls live in Lassen Volcanic National Park, at the northern edge of their range, and to the south in Yosemite and Sequoia and Kings Canyon national parks. North and west of Lassen lies the northern spotted owl's range, which takes in the park units at Whiskeytown, Redwood, Oregon Caves and Crater Lake.

Sources

• National Park Service, Klamath Inventory and Monitoring Network: "California Spotted Owl," Featured Creature, October 2024, prepared by Sonya Daw.