The marbled murrelet (Brachyramphus marmoratus) is a small seabird from the North Pacific. It is a member of the family Alcidae, which includes auklets, guillemots, murres and puffins. It nests in old-growth forests or on the ground at higher latitudes where trees cannot grow. Its population has declined since humans began logging its nest trees in the latter half of the 19th century. The decline of the marbled murrelet and its association with old-growth forests—at least in the southern part of its range—have made it a flagship species in the forest protection movement.

Taxonomy

The marbled murrelet was formally described in 1789 by the German naturalist Johann Friedrich Gmelin in his revised and expanded edition of Carl Linnaeus's Systema Naturae. He placed it with the grebes and loons in the genus Colymbus and coined the binomial name Colymbus marmoratus. Gmelin based his description on the "marbled murrelet" that had been described and illustrated in 1785 by both the English ornithologist John Latham and by the Welsh naturalist Thomas Pennant. Both authors mention the two specimens in the Leverian Museum that had been collected in Prince William Sound during James Cook's third voyage to the Pacific Ocean. Cook described the birds in his account of the voyage.

<blockquote>It is about the size of a partridge; has a short, black, compressed bill; with the head and upper part of the neck of a brown black; the rest of a deep brown, obscurely waved with black, except the underpart, which is entirely of a blackish cast, very minutely varied with white; the other (perhaps the female) is blacker above, and whiter below.</blockquote> The marbled murrelet is now one of three species placed in the genus Brachyramphus that was introduced in 1837 by the German born naturalist Johann Friedrich von Brandt. The genus name combines Ancient Greek brakhus meaning "short" with rhamphos meaning "bill". The specific epithet marmoratus is Latin meaning "marbled". The species is monotypic: no subspecies are recognised.

Description

thumb|Adult Marbled Murrelet on the Oregon Coast adjacent to Oregon Islands National Wildlife Refuge, OR Photo: Roy W. Lowe/USFWS

The marbled murrelet is a small (25&nbsp;cm), chunky auk with a slender black bill. It has pointed wings and plumage that varies by season. The non-breeding plumage is typically white underneath with a black crown, nape, wings and back. The bird closely resembles its congener, the long-billed murrelet; in fact, these species were considered conspecific up until 1998. In breeding plumage, both have a brown mottled body and face. The long-billed has a pale white throat which is lacking in the marbled. In winter plumage, the marbled murrelet has a white neck collar, absent in long-billed. The marbled murrelet is shorter-billed and slightly smaller than the long-billed murrelet.

Distribution and habitat

Marbled murrelets occur in summer from Alaska's Kenai Peninsula, Barren islands, and Aleutian Islands south along the coast of North America to Point Sal, Santa Barbara County, in south-central California. They winter mostly within the same general area, except that they tend to vacate the most northern sections of their range, especially where ice forms on the surface of the fiords. They have been recorded as far south as Imperial Beach of San Diego County, California.

Nesting habitat

From southeast Alaska southward, marbled murrelets use mature or old-growth forest stands near the coastline for nesting. large snags, and numerous downed snags in all stages of decay.

Foraging habitat

Marbled murrelets forage in the ocean near shore and in inland saltwater areas such as bays, sounds, and saltwater passageways. Some also forage on inland freshwater lakes. Flocks of 50 or more birds have been observed near freshwater lakes.

Winter habitat

thumb|Marbled Murrelet (Brachyramphus marmoratus) showing winter plumage

Marbled murrelet winter habitat is the same as the nesting and foraging habitat. During the winter marbled murrelets use inland old-growth or mature sites for roosting, courtship, and investigating nest sites. The use of inland lakes during the nonbreeding season occurs in conjunction with visits to nesting areas. It lays one egg on a platform of lichen or moss on these branches (less often on the ground). In northern populations, murrelets nest on the ground among rocks, as do other related murrelet species. The egg is incubated for a month, then fed for around 40 days until the chick is able to fledge. Adults fly from ocean feeding areas to inland nest sites, mostly at dusk and dawn. They feed nestlings at least once and sometimes twice per day or night. Usually only one fish is carried to the young.

Conservation

Marbled murrelet populations are affected by many environmental processes. Cooler ocean temperatures along with high availability of their prey increases their reproductive success. Loss of their nesting habitat in old-growth trees along with the warming ocean temperatures have serious negative impacts on murrelet populations. Human activity such as commercial fishing, increased boat traffic and pollution decrease the Marbled murrelet non-breeding distribution. Conservation of their inland nesting habitat and their marine breeding and foraging habitats is therefore important.

The Northwest Forest Plan (NWFP) aims at stabilizing the marbled murrelet population via maintaining and increasing their nesting habitat. The population was monitored from 2000 to 2018 and was found to have declined in Washington but increased in Oregon and northern California. This decline in the north could be attributed to habitat loss, long nest-to-sea commutes, or poor foraging habitats in Washington.

Scientists at Redwood National Park have established a connection between human presence in marbled murrelet territory and corvid predation of marbled murrelet chicks.

See also

  • Seabirds
  • Flagship Species
  • IUCN Red List
  • Northwest Forest Plan

References

Further reading

  • "National Geographic" Field Guide to the Birds of North America
  • Seabirds, an Identification Guide by Peter Harrison, (1983)
  • Handbook of the Birds of the World Vol 3, Josep del Hoyo editor,
  • "National Audubon Society" The Sibley Guide to Birds, by David Allen Sibley,
  • Rare Bird: Pursuing the Mystery of the Marbled Murrelet, by Maria Mudd-Ruth,
  • Birdlife International Marbled Murrelet
  • U.S. Fish and Wildlife Marbled Murrelet
  • Research on Marbled Murrelet by Redwood Sciences Laboratory, USFS
  • Research and Nest Photos from Centre for Wildlife Ecology, Simon Fraser University
  • Prof Stephen Sillett's Redwood webpage including a photo of a Marbled Murrelet nest under the "Arboreal Animals" section, 318 feet above the ground.
  • Redwood National Park's "Don't Help a Good Bird Go Bad!" campaign on the relationship between humans, corvid predation, and marbled murrelets.
  • U.S. Fish and Wildlife Service Pacific Region Species Info including a chronology of federal actions.
  • Marbled Murrelet Review 2009 5 Year Review for the Marbled Murrelet.