Marbled Murrelet and Corvid (Jay/Raven/Crow) Fact Sheet For Interpretive Division Staff Redwood National and State Parks

Marbled Murrelet Natural History

Scientific name: Brachyramphus marmoratus. Taxonomic family: Alcidae (murres, puffins, guillemots, etc.). Status: Listed as Federally threatened and State Endangered in California.

Description: Chunky. 10 inches long. Winter plumage dark grey above and white below, adult in summer mottled brown and white. Sexes identical. Common call, heard while flying over inland habitat and at sea, a single note high pitched keer, repeated. Rapid wing beat and flight, average 45-85 mph straight flight with top speed of 98 mph.

Habitat: Ocean (feeding and wintering) – from just outside of surfline to two miles offshore. Inland (nesting) – large coniferous trees, nests on large moss covered branches (4” diameter branches and up, usually > 8” diameter), nest trees found within 50 miles of coast but in California all nests found have been within 18 miles of coast. Approximately 41,000 acres of suitable nesting habitat left within Redwood National and State Parks. Redwood N&SP contains largest remaining block of suitable nesting habitat in California. Majority of suitable nesting habitat within lower 48 states has been logged rendering it unsuitable.

Range: Nesting - Aleutian Islands (Alaska) through southwest Alaska, British Columbia, Washington, Oregon and California south to Santa Cruz county. Wintering – range extends south to Baja California. Large gap in range from Mendocino county to Santa Cruz county.

Food: Small nearshore fish such as sand lance (Ammodytes hexapterus), Pacific herring (Clupea harengus), smelt (Osmeridae), and anchovy (Engraulis spp.). “Flies” underwater to chase fish. Dives usually last less than a few minutes. Maximum dive depth unknown, perhaps 100 feet based on other, similarly sized Alcids.

Breeding: Adult male and female form pair bond for breeding season, unknown if mate for life. First nest discovered in 1973 in Santa Cruz mountains. Nesting begins in late March and extends through September in California, peak nesting period in July. Crepuscular (dawn and dusk) activity when flying to and from nest and feeding chick. Single egg laid. May potentially renest if first nest fails. Incubate for approximately 1 month. Adult male and female incubate on 24 hour shifts, usually switching early in the morning. Once hatched, chick fed by both parents. Chick fledges (leaves nest) in about a month. First flight all the way to ocean. Parental care ends once chick has fledged.

Population Size: Estimated from at-sea surveys. Currently in Alaska and Canada estimated over 200,000 (this subpopulation not listed as threatened). Subpopulation of Washington, Oregon and California listed as threatened. Approximately 4,000 (range 3,000-8,000) in California. The vast majority of murrelets surveyed in California were located off coast of Redwood N&SP. Oregon and Washington contain approximately same numbers of murrelets as California. Estimated 60,000 murrelets in California before modern logging era.

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Corvid (Steller’s Jay/Raven/Crow) Natural History

Steller’s Jay: Scientific name - Cyanocitta stelleri. Taxonomic family – Corvidae. Description – blue and black with crest. Habitat – coniferous forests. Range – Rocky mountains west where habitat exists. Food – generalist (all types). Breeding – long term pair bond, average 4 eggs, approximately month from egg laying to fledging. Population – increasing in Pacific Northwest forests.

Common Raven: Scientific name – Corvus corax. Taxonomic family – Corvidae. Description – all black, large size, large bill, wedge shaped tail. Habitat – generalist (all types). Range – All of North America except Midwest and Southeast. Food – generalist (all types). Breeding – long term pair bond, average 5 eggs, approximately month and a half egg laying to fledging. Population – increasing throughout range.

American Crow: Scientific name – Corvus brachyrhynchos. Taxonomic family – Corvidae. Description – all black, medium size, slimmer bill, square tail. Habitat – generalist (most types). Range – all of North America but deserts and Arctic. Food – generalist (all types). Breeding – cooperative (non-breeding siblings help parents raise young). Population – increasing throughout west, particularly near developed areas.

Other Corvids in Redwood N&SP: Gray Jay (Perisoreus canadensis) – less common. Scrub Jay (Aphelocoma coerulescens) – inland scrub habitat only.

Predation of Marbled Murrelets by Corvids and the Influence of Human Food

Predation is a natural process. Elevated numbers of predators or predators which change natural foraging patterns because of human changes to the environment are not natural processes.

Potential Marbled Murrelet Predators in Redwood N&SP: common raven, Steller’s jay, great horned owl (Bubo virginianus), American crow, sharp-shinned hawk (Accipiter striatus), Cooper’s hawk (A. cooperii), raccoon (Procyon lotor), Pacific fisher (Martes pennanti), Townsend chipmunk (Tamias townsendi), northern flying squirrel (Glaucomys sabrinus), and Douglas squirrel (Tamasciurus douglasii).

Corvids and marbled murrelets: Studies have shown that human food sources (e.g trash, scraps, livestock feed, bird feeders) attract unnaturally high numbers of corvids to an area or change corvid foraging patterns. Areas with high numbers of corvids have high rates of nest predation by corvids on other bird species. Studies have also shown that corvids are major predators of marbled murrelets. Murrelets appear to have a low nest success rate throughout Washington, Oregon and California. Nest predation is suspected to be a primary reason for low reproduction rates in murrelets.

Take Home Message: Feeding birds, intentionally or unintentionally, may result in dead marbled murrelets and an increased risk of extinction.

For more information contact: Keith Bensen – x5277 or [email protected]

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