The Two Birds That Changed What Humboldt's Forests Are For

The northern spotted owl (Strix occidentalis caurina) and the marbled murrelet (Brachyramphus marmoratus) share little in their daily arrangements. One is a nocturnal forest raptor; the other is a small, compact seabird that spends nine months on the open Pacific and has, in the way of seabirds, essentially nothing to do with trees for most of the year. What they share is a single non-negotiable requirement: ancient trees. Not merely large trees, but trees of a specific structural complexity — cavities, broken crowns, moss-covered lateral limbs of unusual diameter — that develop only over centuries, in forests that have not experienced major disturbance within the lifetime of the oldest trees.

In Humboldt County, where the largest remaining stands of old-growth coast redwood and Douglas fir persist in parks and reserves, both species retain populations of consequence. Their federal listing under the Endangered Species Act — the spotted owl in 1990, the marbled murrelet in 1992 — did not create the relationship between these birds and old-growth. It made that relationship legally enforceable, in ways that reshaped the timber economy of Northern California for a generation and preserved the forests that remain standing today.

The northern spotted owl holds a territory of 1,500 to 5,000 acres per breeding pair, depending on forest quality. In stands of old-growth Douglas fir and coast redwood, a pair may require less; in fragmented second-growth, territories expand as the birds search for the structural features they require: large-diameter trees with natural cavities, broken tops, or platform-shaped deformities that develop only after two centuries of growth, windstorm, and fungal decay.

Spotted owls do not build nests. A pair selects an existing cavity — a Douglas fir snag with a broken crown, a redwood burled knob, a cliff face adjacent to dense canopy — and returns to the same site year after year. The female lays two eggs in late winter; the male hunts through the spring and summer, with northern flying squirrels (Glaucomys sabrinus) constituting the primary prey item in Northern California. The connection between spotted owls and flying squirrels, and between flying squirrels and the mycorrhizal truffle fungi they eat and disperse through the forest floor, and between those fungi and the old trees whose roots they colonize — this is the forest's own logic, arriving at ecological conclusions without requiring any particular orchestration.

Listed as Threatened under the federal Endangered Species Act in June 1990, the northern spotted owl immediately triggered legal reviews of timber harvests on federal land throughout its range. A series of injunctions followed, halting old-growth federal timber sales in Oregon, Washington, and Northern California — effectively suspending the commercial old-growth harvest that had been proceeding at its highest rate since the 1950s. The owl's listing was the legal instrument; the old forests were the subject. Lady Humboldt notes that this distinction was not universally appreciated at the time.

The marbled murrelet presents what may be the most counterintuitive arrangement in the ornithology of Humboldt County. For nine to ten months of the year it is entirely a seabird — compact, alcid-shaped, diving for surf smelt and sand lance in nearshore Pacific waters, visible from Trinidad Head as dark specks riding the swells between November and March. Then, in April, it turns inland to nest.

Unlike every other seabird in its family, the marbled murrelet constructs no nest whatsoever. It lays a single egg directly on a large, flat, moss-covered limb of an old-growth tree — typically a Douglas fir, coast redwood, or Sitka spruce of at least 200 years, whose limbs have accumulated the soil-like moss and duff layer that provides the murrelet a secure, insulating platform. The pair commutes daily between the nesting tree and the ocean, a flight of up to 50 miles in each direction, making multiple feeding runs per day through the June through August nesting season. This commuting arrangement is, by any structural analysis, unreasonable. The murrelet does not appear to have noticed.

North American ornithologists had not confirmed a marbled murrelet nest on the continent until 1974, when a tree surveyor discovered one in a Douglas fir in Big Basin Redwoods State Park south of San Francisco — a finding that confirmed what had been suspected from the bird's coastal breeding distribution and complete absence of ground-nesting behavior. Listed as Threatened under the ESA in 1992 for California, Oregon, and Washington, and simultaneously under the California Endangered Species Act, the murrelet became the second major legal instrument by which old-growth protection was advanced in Humboldt County.

Population monitoring by the USDA Forest Service since the 1990s has documented a California decline of approximately 4.3 percent per year. The mechanism is not complicated: old trees, once cut, do not regenerate on any timeline relevant to the birds. A Douglas fir requires roughly 200 years to develop limb structure a murrelet requires for nesting. This fact was available for inspection at any library through the decades of the most intensive harvest.

Both species require what ecologists call old-growth structural attributes — a cluster of forest characteristics that accumulate over centuries and cannot be replicated by a timber harvest and replanting cycle, however carefully managed. The defining features:

• Large-diameter trees: Douglas fir at minimum 80 cm diameter at breast height, preferably 100+ cm; coast redwood at 200+ cm DBH for the structural complexity murrelets require on outer limbs
• Standing snags: dead trees that have not yet fallen, providing the cavity nesting sites spotted owls require and that no younger forest produces
• Multilayered canopy: trees of multiple ages and heights creating shade, moisture retention, and the interior habitat density spotted owls depend on
• Coarse woody debris: fallen logs in multiple stages of decay, which support the flying squirrel population that constitutes the spotted owl's primary prey
• Moss accumulation on large limbs: the multi-century buildup of cryptogamic soil on large lateral branches — the only known nesting substrate for marbled murrelets in the continental United States

A forest achieves these attributes approximately 200 to 250 years after the last major disturbance — natural fire, windstorm, or clear-cut. The old-growth stands remaining in Humboldt County's parks and reserves represent forests undisturbed by major events since the mid-1700s or earlier. They are not, in ecological terms, a stable endpoint. They are a cumulative condition that has no shortcut.

Lady Humboldt notes that low-intensity traditional fire, as practiced by the Karuk and Yurok tribes over millennia, does not reset this structural clock. It maintains understory and prairie openings that the broader ecosystem requires while leaving the old-growth canopy undisturbed — an ecological distinction that took considerable time for non-tribal land managers to understand, and whose understanding is still, by some accounts, incomplete.

In 1986, the Maxxam Corporation completed a hostile takeover of Pacific Lumber Company (PALCO), the Scotia-based timber company that had for decades managed its redwood and Douglas fir holdings at what was described as a sustainable pace. The new ownership accelerated harvest rates substantially, targeting the company's remaining old-growth stands — stands that wildlife biologists had identified as spotted owl territories and murrelet nesting habitat.

The 1990 spotted owl listing provided the legal foundation for injunctions on federal timber sales adjacent to PALCO holdings and for challenges to state timber harvest plans on company land. The 1992 murrelet listing extended similar protections to California state-administered forests. Earth First! organized direct action campaigns in the county through the early 1990s. In December 1997, the activist Julia Butterfly Hill climbed a 1,500-year-old coast redwood in the Stafford Hills area — a tree PALCO had mapped as "Luna" — and remained for 738 days, a period that attracted international press attention to the old-growth campaign and to Humboldt County specifically.

The Headwaters Forest was a 7,472-acre old-growth redwood and Douglas fir grove on PALCO land, the largest unprotected old-growth redwood grove then remaining in private ownership. In 1999, the federal government and the State of California completed a $480 million purchase of the Headwaters grove and the adjacent Elk Head Springs unit. The Bureau of Land Management manages it today as the Headwaters Forest Reserve. A trail enters the reserve from Elk River Road, and visitors arriving in the evening during the February through May nesting season sometimes hear a spotted owl's four-note hoot in the canopy above. The owl did not appear, on balance, to have emerged the loser from these arrangements.

Pacific Lumber Company declared bankruptcy in 2008, carrying the debt load Maxxam had placed on it at the time of the takeover. Timber holdings were restructured across several parties; the company town of Scotia, operated by Pacific Lumber since the 1880s, was sold to private investors. The old trees remained.

The northern spotted owl's primary current threat is no longer the chainsaw. The barred owl (Strix varia), a generalist raptor native to eastern North America, expanded across the continent through the 20th century following the fragmentation of the Great Plains forest corridor and arrived in California in the 1980s. It has been displacing spotted owls throughout their range ever since. Barred owls are larger, more aggressive, and adapt readily to second-growth and edge habitats where spotted owls do not survive. Studies in Northern California indicate that barred owls now occupy large portions of former spotted owl territories in Humboldt's mixed-conifer forests — an outcome the ESA listing was not designed to address, because the barred owl's expansion preceded the listing and originates from the east, not the timber industry.

The U.S. Fish and Wildlife Service conducted experimental barred owl removal trials beginning in 2013 in Northern California, Oregon, and Washington, finding that spotted owl populations stabilized in areas where barred owls were removed. A broader barred owl management strategy was adopted in 2024 with permitted removal operations in prioritized spotted owl strongholds. The birding community has tracked the results with attention.

The marbled murrelet's situation in California is characterized by the USFWS as stable within protected old-growth stands and declining at sites adjacent to fragmented landscapes. The primary remaining California murrelet population is concentrated in the coast redwood parks of Humboldt and Del Norte counties — the same forests that host the spotted owl, the same forests the 1990s campaigns preserved from further harvest. The murrelet, which has been commuting up to 50 miles from the Pacific to nest in old-growth trees for approximately two million years, now depends on the legal status of roughly three percent of the coast redwood's original range.

These facts may be related.

Species	Best Location	Best Season	Best Time of Day	What to Listen and Look For
Northern Spotted Owl	Headwaters Forest Reserve; Humboldt Redwoods old-growth; Prairie Creek Redwoods	February–May (nesting; most vocal)	Dusk through the first two hours of darkness	Four-note hooting sequence; pairs call in alternation; compact brown bird with no ear tufts
Marbled Murrelet	Old-growth interior of Prairie Creek Redwoods (dawn call); Trinidad Head (ocean view)	May–August (nesting season; daily ocean commute)	Pre-dawn (4:30–6:00 AM) for forest calls; any morning from Trinidad Head	High-pitched "keer" call over old-growth canopy; small compact alcid diving offshore from Trinidad Head
Barred Owl	Second-growth Douglas fir; Arcata Community Forest; river corridors	Year-round	Night	Eight-note call, the field-guide mnemonic for which involves a kitchen-labor query; more variable in pitch and delivery than spotted owl hooting

Sources: USDA Forest Service Pacific Southwest Region murrelet monitoring protocol, 2024; USFWS Northern Spotted Owl Recovery Plan, 2021 draft.

Lady Humboldt notes that the distinction between a spotted owl call and a barred owl call — while meaningful to biologists and worth some effort to learn — requires a reference recording for anyone who has not already spent time with both species. The Macaulay Library at the Cornell Lab of Ornithology maintains recordings of both. The difference, once established, becomes obvious in the way that most distinctions become obvious after the evidence has been properly examined.

The Headwaters Forest Reserve offers the most accessible old-growth spotted owl habitat in Humboldt County. The Elk Head Springs Trail runs 5.7 miles from the Elk River Road trailhead through second-growth forest transitioning to old-growth redwood at the grove boundary. Evening visits in February through May, when territorial owls vocalize most consistently, give the best opportunity to hear rather than see the birds. Spotted owls are compact, brown, and heavily spotted; against bark, they vanish with what might be called economy of effort. Lady Humboldt recommends arriving at the trailhead by 5 PM in late February and allowing two hours for the walk to the grove edge and back in the dark.

Marbled murrelets are easier to confirm by call than by direct observation in the forest. In the interior of Prairie Creek Redwoods State Park, the pre-dawn period from mid-May through July produces high-pitched "keer" calls overhead as birds commute between the ocean and nest trees. From the ocean side, the birds are visible from shore as compact, low-flying alcids. The Trinidad Head trail — a short loop around the headland above Trinidad Bay — offers the county's most accessible seabird observation platform, and murrelets are among the species present through the nesting season, diving from the surface and flying low over the swells.

Neither bird is guaranteed at any site. Spotted owl territories shift as barred owls expand, and murrelet nesting trees are not publicized — established protocols exist specifically to limit disturbance to active nest sites. The value in looking is not solely the sight itself but the orientation that comes from standing in a 500-year-old redwood grove at dusk, understanding at some level of attention what it took to keep this place as it is.

The hike directory includes access details for Headwaters Forest Reserve, Prairie Creek Redwoods, and Trinidad Head. Lady Humboldt's weekly field guide arrives Tuesday mornings and tracks the full annual cycle of the county's wildlife calendar, including the spotted owl's late-winter nesting window and the murrelet's spring ocean-to-forest commute. A subscription is here.