Shoreline regions of the north Pacific Ocean: Western - Japan to Kamchatka, Russia, Eastern- central California to southern Alaska.
Biogeographic Regions: nearctic (Native ); palearctic (Native ); pacific ocean (Native )
occurs (regularly, as a native taxon) in multiple nations
Regularity: Regularly occurring
Type of Residency: Year-round
Regularity: Regularly occurring
Type of Residency: Year-round
Global Range: (200,000-2,500,000 square km (about 80,000-1,000,000 square miles)) Breeding range extends from the western Aleutian Islands through coastal southern and southeastern Alaska, British Columbia (up to 100 kilometers inland), Washington, Oregon, and northern central California (mainly Del Norte and northern Humboldt counties to 15 km inland, southcentral Humboldt County 20-40 km inland, and southern San Mateo and northern Santa Cruz counties up to 20 km inland; Carter and Erickson in Carter and Morrison 1992); few occupied sites are known between Tillamook County in Oregon and the Olympic Peninsula in Washington (USFWS 1994). See USFWS (1994) and Federal Register (10 August 1995) for maps of proposed Critical Habitat in California, Oregon, and Washington. During the nonbreeding season, the range extends from southern Alaska south to central California, mostly adjacent to known or suspected nesting areas. Most of the Alaskan population is concentrated offshore of large tracts of coastal coniferous forests in southeastern Alaska (Alexander Archipelago), Prince William Sound, and the Kodiak Archipelago (Piatt and Ford 1993). See Marshall (1988), Carter and Morrison (1992), and Piatt et al. (2007) for further details for specific states and provinces.
Coded range extent pertains to breeding range.
islands, and Aleutian islands south along the coast of North America to
Point Sal, Santa Barbara County, in south-central California [3,16].
Marbled murrelets winter mostly within the same general area, except
that they tend to vacate the most northern sections of their range and
have been recorded as far south as Imperial Beach of San Diego County,
Regional Distribution in the Western United States
This species can be found in the following regions of the western United States (according to the Bureau of Land Management classification of Physiographic Regions of the western United States):
1 Northern Pacific Border
2 Cascade Mountains
3 Southern Pacific Border
Occurrence in North America
U.S.A. (AK, CA, OR, WA), Canada (B.C.)
The Marbled Murrelet is a very small, chubby, sea bird that seems to lack a neck. It has a dark brown to black dorsum and a white venter and throat. The nonbreeding plumage includes a strip of white between the back and the wing, thus the name "marbled". The breeding plumage is dark brown dorsally; ventral feathers are white tipped with brown. Males and females are of approximately the same size, 9.5-10" wingspan. Bill length is 13-18 mm; wing length (relaxed) is 120-140mm. The voice of the Marbled Murrelet is a sharp "keer" or lower "kee."
Other Physical Features: endothermic ; bilateral symmetry
Length: 25 cm
Weight: 222 grams
Resembles Kittlitz's Murrelet but summer plumage lacks buff speckling on upperparts and lacks white-tipped secondaries and white outer tail feathers; also, has a longer bill and, in winter, upperparts are not as gray, nor is the face extensively white (dark around eye instead of white), nor is there a nearly complete breast band. Juvenile diifers from juvenile Kittlitz's Murrelet in having a longer bill and darker face, and by lacking pale outer tail feathers. (NGS 1983, Ridgway 1919).
The general habitat of the Marbled Murrelet is near coastal waters, tide-rips, bays, and mountains. Nesting sites are in higher elevations, exclusively in old growth forests of 175-600 years in age (barring a few ground nests on Alaskan Islands). Nest sites are large, moss covered, horizontal branches with an average height of 45 meters. The sites are often a substantial distance from the coast (Peterson, 1961; Carter and Morrison, 1992; Singer, 1990).
Terrestrial Biomes: forest
Aquatic Biomes: coastal
Habitat and Ecology
Comments: Coastal areas, mainly in salt water within 2 km of shore (Marshall 1988), including bays and sounds; not uncommon up to 5 km offshore; occasionally also on rivers and lakes usually within 20 km of ocean (but up to 75 km), especially during breeding season (Carter and Sealy 1986). In Alaska, marine habitats mostly are offshore of large tracts of old-growth coastal coniferous forest, especially Sitka spruce and hemlock (Piatt and Ford 1993).
In central California, visited old-growth forest nesting areas (8-9 km from ocean) year-round; fall and winter visitation of nesting areas occurs regularly in other areas of North America as well; perhaps attendance in nonbreeding season is important in maintenance of pair bonds and nest sites (Naslund 1993). Nests often are in mature/old growth coniferous forest near the coast: on large mossy horizontal branch, mistletoe infection, witches broom, or other structure providing a platform high in mature conifer (e.g., Douglas-fir, mountain hemlock). Most nesting occurs in large stands of old growth. Nest sites generally have good overhead protection. See Quinlan and Hughes (1990), Singer et al. (1991), and USFWS (1996) for characteristics of tree nests.
In California, most inland activity takes place in or to the west of old-growth stands of 250 ha or more (Paton and Ralph 1990).
On the Queen Charlotte Islands, British Columbia, most inland activity (May-July) was in old growth forest, especially stands of large Sitka spruce and western hemlock (Rodway et al. 1993). Nesting or probable nesting has been recorded up to 47 km and 61 km inland in Oregon (Levy 1993), up to 84 km inland in Washington, and up to 56 km inland in California (USFWS 1994). On the British Columbia coast, nesting birds flew 12-102 kilometers (mean 39 kilometers) inland from foraging sites on the water (Hull et al. 2001).
In Alaska, a few percent of the population nests on islands on open barren ground or in a rock cavity, generally a short distance below a peak or ridge (Day et al. 1983, Carter and Sealy 1986, Marshall 1988, Kuletz 1990, Carter and Morrison 1992). Ford and Brown (1995) reported a clifftop nest in old-growth forest in southeastern Alaska.
Silent individuals flying below the forest canopy indicate nesting in the immediate area (Levy 1993).
Marbled murrelets are coastal birds that occur mainly near saltwater
within 1.2 miles (2 km) of shore . However, marbled murrelets have
been found up to 59 miles (80 km) inland in Washington, 35 miles (56 km)
inland in Oregon, 22 miles (37 km) inland in northern California, and 11
miles (18 km) inland in central California. Over 90 percent of all
marbled murrelet observations in the northern Washington Cascades were
within 37 miles (60 km) of the coast. In Oregon, marbled murrelets are
observed most often within 12 miles (20 km) of the ocean . Many
marbled murrelets regularly visit coastal lakes. Most lakes used by
marbled murrelets are within 12 miles (20 km) of the ocean, but a few
birds have been found at lakes as far inland as 47 miles (75 km). All
lakes used by marbled murrelets occur within potential nesting habitat
Nesting habitat - From southeast Alaska southward, marbled murrelets use
mature or old-growth forest stands near the coastline for nesting
[4,7,16,27]. These forests are generally characterized by large trees
(>32 inches [80 cm] d.b.h.), a multistoried canopy, moderate to high
canopy closure or an open crown canopy [17,26], large snags, and
numerous downed snags in all stages of decay . Marbled murrelets
tend to nest in the oldest trees in the stand . In Oregon, forests
begin to exhibit old-growth characteristics at about 175 to 250 years of
age . Moss, on which marbled murrelets nest, forms on the limbs of
Douglas-fir that are more than 150 years old [16,17].
The only four marbled murrelet tree nests found before 1990 shared the
following characteristics: (1) located in a large tree (>47 inches [120
cm] d.b.h.) with an open crown structure, (2) on a moss-covered limb
that is camouflaged, partially shaded, and approximately horizontal with
a diameter (including associated moss) of at least 14 inches (36 cm),
and (3) located within the middle or lower part of a live crown .
However, Marshall  stated that because of their low aerial bouyancy
marbled murrelets often nest high in the treetops or on steep slopes.
Habitat must be sufficiently open to allow for easy flight . All
marbled murrelet nests found in Washington, Oregon, and California were
located in old-growth trees that ranged from 38 inches (88 cm) d.b.h. to
210 inches (533 cm) d.b.h. with a mean of 80 inches (203 cm) d.b.h.
Nests were located high above the ground and had good overhead
protection but allowed easy access to the exterior forest . Marbled
murrelets may use the same nest in successive years [17,29].
Stand size is also important in nest sites. Marbled murrelets more
commonly occupy stands greater than 500 acres (202 ha) than stands less
than 100 acres (40 ha). However, marbled murrelets may nest in remnant
old-growth trees or groves that are surrounded by younger trees .
In California, marbled murrelets are usually absent from stands less
than 60 acres (24 ha) in size. In Washington, marbled murrelets are
found more often when old-growth and mature forests make up over 30
percent of the landscape. Fewer marbled murrelets are found when
clearcut and meadow areas make up more than 25 percent of the landscape.
Concentrations of marbled murrelets offshore are almost always adjacent
to old-growth or mature forests onshore [4,16], although marbled
murrelets may not use the interior of dense stands .
Where large trees are absent in the northern parts of marbled murrelet
range, marbled murrelets nest in depressions on the ground, in rock
cavities on the ground, or on rock outcrops [9,13,25,26]. Marbled
murrelets are both ground nesters and tree nesters where forests and
treeless areas meet .
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 .
Subadults occur at sea throughout the summer. Sealy  determined
that marbled murrelets feed within 1,640 feet (500 m) of shore.
Winter habitat - 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 [17,18]. The use of inland lakes during the
nonbreeding season occurs in conjunction with visits to nesting areas
Associated Plant Communities
In northern regions where coniferous forests nest sites are unavailable,
marbled murrelets occupy alpine or tundra near the ocean . In
Washington and Oregon, marbled murrelets commonly nest in Douglas-fir
(Pseudotsuga menziesii) dominated stands. They also select stands
dominated by mountain hemlock (Tsuga mertensiana), western redcedar
(Thuja plicata), and Sitka spruce (Picea sitchensis) for nesting [4,16].
In California, nests are most often located in redwood (Sequoia
sempervirens) dominated stands with scattered Sitka spruce, western
hemlock (Tsuga heterophylla) and Douglas-fir. Marbled murrelets also
occur in stands dominated by Port-Orford-cedar (Chamaecyparis
This species is known to occur in the following ecosystem types (as named by the U.S. Forest Service in their Forest and Range Ecosystem [FRES] Type classification):
FRES24 Hemlock-Sitka spruce
Habitat: Cover Types
This species is known to occur in association with the following cover types (as classified by the Society of American Foresters):
205 Mountain hemlock
223 Sitka spruce
224 Western hemlock
225 Western hemlock - Sitka spruce
226 Coastal true fir - hemlock
227 Western redcedar - western hemlock
228 Western redcedar
229 Pacific Douglas-fir
230 Douglas-fir - western hemlock
234 Douglas-fir - tanoak - Pacific madrone
Habitat: Plant Associations
This species is known to occur in association with the following plant community types (as classified by Küchler 1964):
K001 Spruce - cedar - hemlock forest
K002 Cedar - hemlock - Douglas-fir forest
K003 Silver fir - Douglas-fir forest
K004 Fir - hemlock forest
K006 Redwood forest
Water temperature and chemistry ranges based on 17 samples.
Depth range (m): 0 - 0
Temperature range (°C): 12.397 - 15.174
Nitrate (umol/L): 0.604 - 3.951
Salinity (PPS): 30.822 - 33.311
Oxygen (ml/l): 5.858 - 6.393
Phosphate (umol/l): 0.407 - 0.674
Silicate (umol/l): 2.773 - 11.312
Temperature range (°C): 12.397 - 15.174
Nitrate (umol/L): 0.604 - 3.951
Salinity (PPS): 30.822 - 33.311
Oxygen (ml/l): 5.858 - 6.393
Phosphate (umol/l): 0.407 - 0.674
Silicate (umol/l): 2.773 - 11.312
Note: this information has not been validated. Check this *note*. Your feedback is most welcome.
Non-Migrant: Yes. At least some populations of this species do not make significant seasonal migrations. Juvenile dispersal is not considered a migration.
Locally Migrant: Yes. At least some populations of this species make local extended movements (generally less than 200 km) at particular times of the year (e.g., to breeding or wintering grounds, to hibernation sites).
Locally Migrant: No. No populations of this species make annual migrations of over 200 km.
An adult murrelet was observed carrying a fish, presumably for a hatchling. Murrelets eat primarily fish, including Pacific sandlance, Pacific herring, and seaperch. They forage for food solitarily or in pairs, sometimes amongst mixed species feeding flocks (Carter and Morrison, 1992).
Comments: Diet includes fishes (sandlance, capelin, herring, etc.), crustaceans (mysids, euphausiids), mollusks. In British Columbia, adult diet during the breeding season is mostly fishes, primarily Pacific Sandlance and Pacific Herring; euphausiids are important in spring at Langara Island; sandlance are the prey most frequently fed to nestlings (Rodway et al., in Carter and Morrison 1992). May feed exclusively on freshwater prey for period of several weeks in some areas; feeds on fingerling Sockeye Salmon and salmon fry in some British Columbia lakes (Carter and Sealy 1986). Foraging occurs mainly in waters up to 80 m deep and up to 2 km from shore. Foraging dives may be up to about 30 m below surface.
invertebrates [16,17]. Some principal foods include sand lance
(Ammodytes hexapterus), Pacific herring (Clupea haringus), capelin
(Mallotus villosus), and the invertebrates Euphausia pacifica and
Thysanoessa spinifera [16,17,23].
Marbled murrelets do not feed in large flocks as do other alcids,
although loose aggregations occur in winter. While feeding during the
breeding season marbled murrelets occur in pairs or as single
individuals. Subadults feed singly; but in early July, when pairs of
adults are still feeding young, mixed flocks begin to form .
Marbled murrelets feed during the day and at night .
prey on marbled murrelet eggs and nestlings .
Number of Occurrences
Note: For many non-migratory species, occurrences are roughly equivalent to populations.
Estimated Number of Occurrences: Unknown
Comments: Total number of occurrences has not been determined using standardized criteria. Determination of the number of occurrences would be necessarily arbitrary and not particularly informative with regard to the conservation status of this species.
Specific nesting and foraging areas are still being described (Simons 1980; Day et al. 1983; Marshall 1988; Carter and Sealy 1987; Quinlan and Hughes 1990; Singer et al. 1991; Ralph et al. 1995).
100,000 - 1,000,000 individuals
Comments: Total population size is about 388,000, with about 18,000 in Washington-Oregon-California, 54,000-92,000 in British Columbia, and around 271,000 in Alaska (Carter and Morrison 1992, Speich et al. 1992, Speich and Wahl 1995, Varoujean and Williams 1995, Ralph et al. 1995, McShane et al. 2004, Piatt et al. 2007, Falxa et al. 2009, COSEWIC 2012).
Solitary, or in pairs, small groups, or loose aggregations. In most areas, generally does not flock with other birds, but may participate in mixed-species feeding flocks in the absence of interference from larger diving birds (Mahon et al. 1992).
The only confirmed record of predation on an adult at its nest involved a Sharp-shinned Hawk in Alaskan old-growth forest (Marks and Naslund 1994).
Species has high fidelity to nesting areas and nest trees (see Nelson 1997).
Despite the urgent need for an assessment of the demographic state of populations, the species is so secretive that reliable estimates of the required vital rates are rare. Survival estimates obtained through capture-recapture data from a population in British Columbia were 0.8289 and 0.9289, based on different samples corresponding to two capture techniques. The study area had been and continues to be heavily logged (Cam et al. 2003).
Habitat-related Fire Effects
Because marbled murrelets depend on mature or old-growth stands for
nesting and roosting, fires that destroy or reduce the size of these
stands will probably have an adverse effect on marbled murrelet
populations. However, marbled murrelets sometimes nest in unlogged
mature or large sawtimber stands burned 80 to 200 years ago where open
crown canopies or steep slopes exist to provide access to and from large
Marbled murrelets nest in habitat types characterized by long fire free
intervals. Sitka spruce stands in western Washington typically have a
fire free interval of 1,146 years or more. Along the northern and
southern Oregon coast, Sitka spruce has a fire free interval of 200 to
400 years. Fires that do occur in Sitka spruce are usually stand
replacing. Western hemlock forests along the coast have a fire free
interval of about 750 years . Coastal redwood is tolerant of
low-severity fires which appear to have occurred on mesic sites at
200-to 500-year intervals before the arrival of European settlers
Timing of Major Life History Events
at least 2 years old .
Nesting and brooding - Marbled murrelets nest from mid-April to late
September . Peak activity occurs from mid-June to late July in
California, and the second week of July to mid-August in Oregon .
Marbled murrelet are semicolonial in nesting habits. Two nests found in
Washington were located only 150 feet (46 m) apart. Not all mature
adults nest every year . Marbled murrelets lay only one egg. The
egg is incubated by both parents for about 30 days. 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 [4,16].
Fledging - Nestlings fledge in 28 days. Young marbled murrelets remain
in the nest longer than other alcids and molt into their juvenile
plumage before leaving the nest . Fledglings fly directly from the
nest to the ocean .
Migration - Some marbled murrelet populations probably migrate south in
fall and north in spring. However, these migration patterns are not
well understood .
Life History and Behavior
Perception Channels: visual ; tactile ; acoustic ; chemical
Comments: Young are fed at night or around dusk or dawn. Feeding has been observed at night (Carter and Sealy 1986). At Redwood Experimental Forest, northwestern California, activity levels were greatest 30 minutes before to 30 minutes after sunrise in May, June, and July (Paton et al., in Carter and Morrison 1992). In old growth forest in the Queen Charlotte Islands, British Columbia, number of detections peaked in late July; detections were most likely to occur on cloudy mornings (Rodway et al. 1993).
Status: wild: 120 months.
Lifespan, longevity, and ageing
The Marbled Murrelet breeds on mountains near the coast. Breeding season is from mid-April to the end of August. Females have been collected with shelled eggs in their oviducts from April 23 to July 13. The murrelet has single egg clutches. Murrelets may not fledge young until mid-September, based on a 30-day incubation and a 28-day rearing period. Nesting sites are almost exclusively in old-growth forests, yet some have been found in cavities in subalpine areas, and on the ground on islands. Murrelet eggs are yellowish and spotted. The first known nest was found in a rock slide far above the timber line at 1900 ft. on Chicago Island, Alaska, on June 13, 1931. (Peterson,1961; Carter and Morrison, 1992).
Key Reproductive Features: iteroparous ; gonochoric/gonochoristic/dioecious (sexes separate); sexual ; oviparous
Nesting season: late March to late September; downy young, and fledged juveniles have been observed June-September. Activity in forest nesting areas is highest from mid-April through late July in California and Oregon, early May through early August in Washington, and mid-May through early August in Alaska (see Levy 1993). Clutch size is 1. Incubation lasts about 30 days, by both sexes alternately in 24-hr shifts. Nestling is visited and fed by parent 2-4 times each day, fledges in 27-40 days (Marshall 1988, Levy 1993). Appears to nest semicolonially (see USFWS 1994). In a study on the British Columbia coast, foraging distance from nest (i.e. energy spent commuting) had no influence on nesting success (Hull et al. 2001). Generation time is around 10 years (COSEWIC 2012).
Molecular Biology and Genetics
Barcode data: Brachyramphus marmoratus
Below is a sequence of the barcode region Cytochrome oxidase subunit 1 (COI or COX1) from a member of the species.
See the BOLD taxonomy browser for more complete information about this specimen and other sequences.
-- end --
Download FASTA File
Statistics of barcoding coverage: Brachyramphus marmoratus
Public Records: 6
Specimens with Barcodes: 11
Species With Barcodes: 1
The Alaskan population is estimated at 250,000 birds, centered in south central and south eastern parts of the state, but extending into Bristol Bay and along the Aleutian Islands. This represents the bulk of the North American population. Logging efforts are expanding in the areas of the greatest murrelet population. Continued logging will produce major declines in murrelet numbers. Inland records from British Columbia, Washington, and Oregon suggested the presence of nests in old growth forests, although none had been found prior to 1990. Marbled Murrelet numbers in British Columbia are an estimated 45,000-50,000 birds, with the highest density on the west coast of Vancouver Island. The Marbled Murrelet population of Washington is estimated at 5,000, centered in the northern Puget Sound area. Oregon's population is estimated at 2,000-4,000 birds, located mostly in the central coastal region. There is also a small population of murrelets, (1400-1700 birds) on the north central coast of California.
Threats include mainly the loss of old-growth forests (all locales), some mortality from gill nets (responsible for the annual death of 7.8% of the British Columbia population), and oil pollution (Alaska and Washington). Very little of the existing old-growth forests are currently protected. One locale of substantial old growth forest in British Columbia was expected to decrease 95% in 50 years due to harvest schedules. Four of the five locations where fledglings were found in Washington state have been logged. Of Oregon's old growth forests, 44% is in stands of less than 32 hectares or within 122 meters of a clearcut. This isolation of small patches of forest may decrease reproductive success and increase predation at nest sites. In California, only 4% of the original acreage of Redwood trees is currently protected. This obliteration of habitat could be responsible for the sparse numbers of murrelet in California.
The Marbled Murrelet is considered endanged in California, and threatened in Oregon, Washington, and British Columbia. Its low reproductive rate prevents fast recovery from population decreases. The Marbled Murrelet is one of the few species of alcids whose known and suspected nesting habitat is not protected by federal refuge designation. Several lawsuits have been filed to defer the logging of old-growth forests where murrelets are known or suspected to live. In order to save the habitat of the marbled murrelet there need to be larger forest reserves and/or substantial changes in the logging practices.
Ground searches produced only 15 nest locations up until 1987
Tree searches since then have produced 19 nest locations in old growth forests. Due to the difficulty of locating the nests of these elusive birds, it is necessary to implement plans for further research before the Marbled Murrelet becomes an indicator species such as the spotted owl (Carter and Morisson, 1992).
IUCN Red List of Threatened Species: endangered
IUCN Red List Assessment
Red List Category
Red List Criteria
National NatureServe Conservation Status
Rounded National Status Rank: N3 - Vulnerable
Rounded National Status Rank: N3 - Vulnerable
NatureServe Conservation Status
Rounded Global Status Rank: G3 - Vulnerable
Reasons: Extensive range along the Pacific coast of North America from Alaska to California; population numbers still high in British Columbia and Alaska, but declining; threats from habitat loss due to logging, oil spills, and gill net fisheries are increasing.
Rank of G3 was confirmed using NatureServe Rank Calculator Version 3.1.
Intrinsic Vulnerability: Moderately vulnerable
Comments: Low reproductive rate (1 egg/pair/season); slow recovery rate.
Date Listed: 10/01/1992
Lead Region: Pacific Region (Region 1)
Where Listed: U.S.A. (CA, OR, WA)
Population location: U.S.A. (CA, OR, WA)
Listing status: T
For most current information and documents related to the conservation status and management of Brachyramphus marmoratus , see its USFWS Species Profile
United States is available at NatureServe.
Global Short Term Trend: Decline of 50-70%
Comments: Compiling available abundance information, Piatt et al. (2007) estimated that in the recent past, the marbled murrelet population in Alaska numbered on the order of 1 million birds). Information from at-sea surveys spanning a wide geographic range in Alaska indicated that murrelet numbers declined significantly at five of eight trend sites at annual rates of -5.4 to -12.7 percent since the early 1990s. Applying these rates of decline to the historical population estimate, Piatt et al. (2007) estimated the current murrelet population in Alaska to be on the order of 270,000 birds. This represents an overall population decline of about 70 percent during the past 25 years.
Piatt et al. (2007) were not able to generate a similar estimate for historical population size in British Columbia, but available trend data indicate that murrelet populations there also have declined, at a rate of 22 percent over the past three generations (1978-2008), based on habitat trends. Projected rate of decline in British Columbia over the next 30 years exceeds 30 percent (COSEWIC 2012).
On the southern coast of Washington, north coast of Oregon, and in California south of Humboldt County, murrelets are rare or uncommon where they once were common or abundant in the early 1900s (Ralph et al. 1995). Decline in Washington, Oregon, and California in 2001-2008 was 4.3 percent per year (Falxa et al. 2009).
Global Long Term Trend: Decline of 70 to >90%
Degree of Threat: High - medium
Comments: Most populations are dependent on large trees in old-growth forests for nest sites. Continued harvest of old-growth and mature coastal coniferous forest that reduces critical nesting habitat is a major concern throughout most of the range (Sealy and Carter 1984, Marshall 1988, Mendenhall 1992, Rodway et al. 1992, Leschner and Cummins 1992, Nelson et al. 1992, Carter and Erickson 1992, Carter and Morrison 1992; see also Rodway 1990 COSEWIC report). Marbled murrelets have lost about 15 percent of their suitable nesting habitat in Southeast Alaska, and 33 to 49 percent in British Columbia, from industrial-scale logging within the past half century (Piatt et al. 2007). Ralph (1994) estimated that 80 percent of the old-growth forests within the range of this species in the Pacific Northwest had been removed over the last 150 years.
Marbled murrelets are vulnerable to incidental mortality associated with salmon gillnet fisheries (Sealy and Carter 1984, Wynne et al. 1991). The gill-net threat is greatest north of Oregon (Levy 1993). Annual bycatch mortality in salmon gillnetting operations in British Columbia and in Alaska (especially in Prince William Sound and Southeast Alaska) is likely in the low thousands per year, although bycatch rates are difficult to measure (Piatt et al. 2007).
The species' inshore distribution coincides with high levels of vessel traffic and makes them especially vulnerable to both chronic oil pollution and to catastrophic spills (King and Sanger 1979, King 1984, Sealy and Carter 1984, Mendenhall 1992, Rodway et al. 1992, Leschner and Cummins 1992, Nelson et al. 1992, Carter and Erickson 1992, Piatt et al. 2007). The 1989 Exxon Valdez oil spill in south-central Alaska is estimated to have killed 12,000 to 15,000 murrelets (Piatt et al 2007).
Other threats include direct and indirect mortality associated with the location and operation of mariculture facilities. These threats include: entanglement, displacement of birds from traditional foraging areas, contamination of foods by antibiotics, antifoulants, and alteration of local food supplies due to decomposition of fish food and fish excrement associated with these farms (Vermeer and Morgan 1989, Rodway et al. 1992, Leschner and Cummins 1992). Murrelets in some areas may also be subject to high levels of industrial pollutants (Fimreite et al. 1971, Rodway et al. 1992).
Listed populations are currently experiencing very low recruitment rates, due at least in part to nest predation (by edge species, such as bald eagle, common raven, and Steller's jay, that are now more abundant due to forest fragmentation) and probably high mortality in young prior to reaching the ocean (USFWS 1994, 1996). Populations in the Aleutians may have been higher before foxes were introduced there (Mendenhall in Carter and Morrison 1992).
Finally, nesting habitat losses cannot explain the declines observed in areas where industrial logging has not occurred on a large scale (e.g., Prince William Sound) or at all (Glacier Bay) (Piatt et al. 2007). Those declines probably are related to combined and cumulative effects from climate-related changes in the marine ecosystem (most likely the 1977 regime shift) and human activities (logging, gillnet bycatch, oil pollution) (Piatt et al. 2007).
It is Threatened in all range states except Alaska. Detailed conservation recommendations were made in 1995 (Ralph et al. 1995). Federal land-use in the USA is regulated, areas for management identified, and some temporarily removed from logging (Nelson 1997), though the protected status of old-growth forest in California is currently under review by the USFWS in response to a timber-industry-led petition. In July 2008, the USFWS proposed a limited revision to critical habitat for the species in Oregon and Northern California. The Pacific Seabird Group (PSG) filed an objection to the removal of critical habitat designation in some counties in Oregon, but concurred with the proposed critical habitat revisions in northern California and southern Oregon (Harrison 2008). USFWS initiated a status review of the species in 2008, which will also function as a 5-year status review (Harrison 2008). In Canada there has been extensive research, a (now outdated) Recovery Plan (Kaiser et al. 1994), some (relatively minor) habitat protection under the British Columbia Forest and Range Practices Act, more extensive protection of forest habitat under various Land Use agreements and a radar monitoring plan developed by the Canadian Marbled Murrelet Recovery Team (CMMRT 2003). The Canadian Marbled Murrelet Recovery Team developed a Recovery Strategy to be compliant with the Canadian Species at Risk Act. This Recovery Strategy was based on a thorough conservation assessment (CMMRT 2003) approved by the multi-stakeholder team and submitted to the Canadian and British Columbia governments in 2006, but has been shelved since then (A. E. Burger in litt. 2012). The Canadian Marbled Murrelet Recovery Team (CMMRT) also oversaw the completion of a SARA-compliant Marbled Murrelet Nesting Habitat Recovery Action Plan dealing with forest habitat; this too was submitted to the governments in 2006 and has since received no attention (A. E. Burger in litt. 2012). The Department of Natural Resources (WDNR) began developing a Marbled Murrelet Long-Term Conservation Strategy in 2007 (Escene 2007). The Northwest Forest Plan (2006) is expected to ensure the protection of a large proportion of important habitats in the USA (Raphael 2006). Extensive areas of suitable forest nesting habitat have been set aside in conservancies on the northern and central mainland and in Haida Gwaii (formerly Queen Charlotte Islands) (COSEWIC 2012). Smaller areas are being protected by other forestry and conservation measures. Overall, an estimated 35% of the 1,826,828 hectares of suitable habitat in all of British Columbia (based on the Canadian Marbled Murrelet Recovery Team modeling criteria [CMMRT 2003]) had been protected under various measures by 2011 (COSEWIC 2012). In 1998, the Exxon Valdez Trustee Council protected 179 km2 of Afognak Island (BBC Wildlife 1999 172: 23). In 2007, 1,569 ha of forested land on the Oregon Coast was acquired under conservation easement for the species (amongst others), part funded by the New Carissa oil-spill funds (Escene 2007). Between 1998 and 2002, 507 Marbled Murrelets were radio-tracked in British Columbia (Barrett et al. 2008) and during 2005-2007, 111 birds were radio-tracked at Port Snettisham, Alaska, to determine nesting habitat, activity patterns and distribution (Nelson et al. 2008). A recommended protocol for surveying the species in forests was published in 2003 by PSG (Mack et al. 2003). In British Columbia standard protocols have been developed for various survey methods (RIC 1997, Burger 2004). Research has shown that habitat management at relatively fine scales may provide conservation benefits (Horton 2008) and that the species would benefit from a reduction in the amount of hard edges (recent clear-cuts) at both patch and landscape scales (Malt and Lank 2007, 2009).
Conservation Actions Proposed
Survey potential nesting habitat. Collect data on the ratio of juvenile to adult birds from sites throughout the range, and monitor over time, as this is thought to be a reliable indicator of productivity (Peery et al. 2007). Research means of improving the abundance of high quality food, e.g. small fish, during the pre-breeding period. Minimise damage to fish stocks and feeding areas (RENEW Report 1999 9: 20). Conduct research on the behaviour of migrants to determine the extent to which dispersal results in gene flow and prevents declines in resident populations (Peery et al. 2010). Complete and implement the SARA-compliant Canadian Marbled Murrelet Recovery Strategy and the Action Plans proposed therein (CCMMRT 2003). Protect nesting habitat (K. J. Kuletz in litt. 1999). Move campgrounds away from old-growth areas in Californian State Parks, in order to reduce predator populations in breeding areas. Reduce oil-spills, gill-net mortality and logging (K. J. Kuletz in litt. 1999). List as Threatened in Alaska (K. J. Kuletz in litt. 1999).
Management Requirements: See U.S. Forest Service et al. (1993), Thomas et al. (1993), and USFWS (1994) for discussions of management issues.
Biological Research Needs: Further research is needed on methods for measuring population status and change, adult mortality (major sources, density dependence, seasonal concordance), and the movements of wintering populations (Piatt et al. 2007).
Global Protection: Few to several (1-12) occurrences appropriately protected and managed
Comments: Protected under the Migratory Bird Treaty in the United States and Canada and also under the Endangered Species Act in the United States. It is federally listed as a Threatened species in Washington, Oregon, and California and is a former candidate species (Category 2) in Alaska (USFWS 1992a, b). The status of the Alaska population is
currently under review (Robards et al. 2003).
U.S. Fish and Wildlife Service (1996) designated Critical Habitat in Washington, Oregon, and California. Critical Habitat included 32 Critical Habitat Units that were considered essential to the conservation of the species. The National Audubon Society recently purchased habitat in Oregon along Tenmile Creek, an area that supports the largest concentration of Marbled Murrelets in that state (Ehrlich et al. 1992).
Protected under the federal Species at Risk Act (SARA) in Canada. In British Columbia, the Marbled Murrelet is a "Red" listed species (candidate for official extirpated, endangered or threatened status in BC; Fraser et al. 1999).
Needs: Protect critical old-growth nesting and feeding areas; increase response capability against oil spills; monitor gill net takes and regulate harvests to minimize murrelet mortality; prevent pollution of feeding areas; prevent displacement of murrelets from historic foraging areas by disturbance and development.
over the southern portions of its range is harvesting of old-growth and
mature forests . Old growth harvesting has been heavier in coastal
forests than further inland; and short rotation ages (currently < 80
years) do not allow conifers to develop the large diameter flat limbs
with thick moss layers used for nesting. Old-growth and mature forests
within the range of marbled murrelets are essential to marbled murrelet
Mortality from gill-net fisheries - Marbled murrelets are the alcid most
frequently killed by gill-nets. In Barkley Sound off Vancouver Island,
British Columbia, an estimated 380 marbled murrelets were killed by
gill-nets in 1980. This accounted for 7.8 percent of the potential fall
population in the area . Sealy and Carter  reported that 600 to
800 or more marbled murrelets are killed (almost exclusively at night)
annually in Prince William Sound, Alaska, due to gill-nets. Recommended
conservation measures include changes in areas where the gill-net
fishery takes place and prohibition of night fishing. Gill-net fishing
does not occur off the Oregon coast, but is widespread in Puget Sound
Mortality from oil pollution - Marbled murrelets have been rated as
having the highest oil vulnerability index of any seabird in southeast
Alaska. This is based in part on their feeding in loose aggregations
close to shore. Development in the petroleum industry along the Pacific
coast will increase the threat of oil pollution .
Relevance to Humans and Ecosystems
If additional research finds that the marbled murrelet lives exclusively in old-growth forests and that their numbers decrease proportionally with the decrease in acres of forest, then it could be deemed an indicator species thus a justifiable deterent for further logging operations. The decrease in logging leads to a loss of income and jobs in the logging industry (Carter, Morrison).
Increasing numbers of people are spending considerable sums of money to reach marine bird viewing areas off the coasts of North American States and Provinces. These "nonconsumptive pursuits" (Barry, 1979) contribute significant amounts of money to regional economies. Also, there are indirect commercial benefits. Marine birds play significant roles in their complex ecosystem. Disruption of that ecosystem by the extinction of sea birds could have an adverse affect on the fishing industry. Marine bird excrement, (.12-.24 million tons annually!!) is especially rich in nitrates and phosphates, which phytoplankton, the basis of ocean food pyramids, requires (Berry, 1979).
The marbled murrelet (Brachyramphus marmoratus) is a small seabird from the North Pacific. It is a member of the auk family. It nests in old-growth forests or on the ground at higher latitudes where trees cannot grow. Its habit of nesting in trees was suspected but not documented until a tree-climber found a chick in 1974, making it one of the last North American bird species to have its nest described. The marbled murrelet has declined in number 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 preservation movement. In Canada (north of 50° North Latitude) and Alaska, the declines are not so obvious because populations are much larger and the survey techniques have not had sufficient power to detect changes.
The marbled murrelet is a small (25 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 closest relative, 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, 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.
Behavior and breeding
The marbled murrelet feeds at sea both in pelagic offshore areas (often associating with upwellings) and inshore in protected bays and fiords. It feeds principally on sandeels, also taking herring, capelin and shiner perch. The bird has not been known to wander from the Pacific coast of North America, all inland and eastern Brachyramphus records being of the closely related long-billed murrelet.
The nesting behavior of the marbled murrelet is unusual, since unlike most alcids it does not nest in colonies on cliffs or in burrows, but on branches of old-growth and mature conifers such as western hemlock, Sitka spruce, Douglas fir and coastal redwood, as far as 80 km inland. 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. The chick then leaves the nest and flies unaccompanied to the sea. Breeding success is low and chick mortality high.
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. Marbled murrelets 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.
In northern regions where coniferous forests nest sites are unavailable, marbled murrelets occupy alpine or tundra near the ocean. In Washington and Oregon, marbled murrelets commonly nest in Douglas-fir (Pseudotsuga menziesii) dominated stands. They also select stands dominated by mountain hemlock (Tsuga mertensiana), western redcedar (Thuja plicata), and Sitka spruce (Picea sitchensis) for nesting. In California, nests are most often located in redwood (Sequoia sempervirens) dominated stands with scattered Sitka spruce, western hemlock (Tsuga heterophylla) and Douglas-fir. Marbled murrelets also occur in stands dominated by Port-Orford-cedar (Chamaecyparis lawsoniana).
Major life events
Marbled murrelets do not breed until they are at least 2 years old. Marbled murrelets nest from mid-April to late September. Peak activity occurs from mid-June to late July in California, and the second week of July to mid-August in Oregon. Marbled murrelet are semicolonial in nesting habits. Two nests found in Washington were located only 150 feet (46 m) apart. Not all mature adults nest every year. Marbled murrelets lay only one egg. The egg is incubated by both parents for about 30 days. 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.
Nestlings fledge in 28 days. Young marbled murrelets remain in the nest longer than other alcids and molt into their juvenile plumage before leaving the nest. Fledglings fly directly from the nest to the ocean.
Marbled murrelets are coastal birds that occur mainly near saltwater within 1.2 miles (2 km) of shore. However, marbled murrelets have been found up to 59 miles (95 km) inland in Washington, 35 miles (56 km) inland in Oregon, 22 miles (37 km) inland in northern California, and 11 miles (18 km) inland in central California. Over 90% of all marbled murrelet observations in the northern Washington Cascades were within 37 miles (60 km) of the coast. In Oregon, marbled murrelets are observed most often within 12 miles (20 km) of the ocean. Many marbled murrelets regularly visit coastal lakes. Most lakes used by marbled murrelets are within 12 miles (20 km) of the ocean, but a few birds have been found at lakes as far inland as 47 miles (75 km). All lakes used by marbled murrelets occur within potential nesting habitat.
From southeast Alaska southward, marbled murrelets use mature or old-growth forest stands near the coastline for nesting. These forests are generally characterized by large trees (>32 inches [80 cm] diameter at breast height (d.b.h.)), a multistoried canopy, moderate to high canopy closure or an open crown canopy, large snags, and numerous downed snags in all stages of decay. Marbled murrelets tend to nest in the oldest trees in the stand. In Oregon, forests begin to exhibit old-growth characteristics at about 175 to 250 years of age. Moss, on which marbled murrelets nest, forms on the limbs of Douglas-fir that are more than 150 years old.
The only four marbled murrelet tree nests found before 1990 shared the following characteristics: (1) located in a large tree (>47 inches [120 cm] d.b.h.) with an open crown structure, (2) on a moss-covered limb that is camouflaged, partially shaded, and approximately horizontal with a diameter (including associated moss) of at least 14 inches (36 cm), and (3) located within the middle or lower part of a live crown. However, Marshall  stated that because of their low aerial buoyancy marbled murrelets often nest high in the treetops or on steep slopes. Habitat must be sufficiently open to allow for easy flight. All marbled murrelet nests found in Washington, Oregon, and California were located in old-growth trees that ranged from 38 inches (88 cm) d.b.h. to 210 inches (533 cm) d.b.h. with a mean of 80 inches (203 cm) d.b.h. Nests were located high above the ground and had good overhead protection but allowed easy access to the exterior forest. It was initially believed that marbled murrelets might use the same nest in successive years but there has been little evidence of this.
Stand size is also important in nest sites. Marbled murrelets more commonly occupy stands greater than 500 acres (202 ha) than stands less than 100 acres (40 ha). However, marbled murrelets may nest in remnant old-growth trees or groves that are surrounded by younger trees. In California, marbled murrelets are usually absent from stands less than 60 acres (24 ha) in size. In Washington, marbled murrelets are found more often when old-growth and mature forests make up over 30% of the landscape. Fewer marbled murrelets are found when clearcut and meadow areas make up more than 25% of the landscape. Concentrations of marbled murrelets offshore are almost always adjacent to old-growth or mature forests onshore, although marbled murrelets may not use the interior of dense stands.
Where large trees are absent in the northern parts of marbled murrelet range, marbled murrelets nest in depressions on the ground, in rock cavities on the ground, or on rock outcrops. Marbled murrelets are both ground nesters and tree nesters where forests and treeless areas meet.
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. Subadults occur at sea throughout the summer. Marbled murrelets feed within 1,640 feet (500 m) of shore.
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.
Marbled murrelets feed below the water surface on small fish and invertebrates. Some principal foods include sand lance (Ammodytes hexapterus), Pacific herring (Clupea haringus), capelin (Mallotus villosus), and the invertebrates Euphausia pacifica and Thysanoessa spinifera.
Marbled murrelets often forage in pairs but do not feed in large flocks as do other alcids. Loose aggregations of 500 or more birds occasionally occur in winter. DNA tests have shown that the foraging duos are not necessarily breeding pairs. Subadults feed singly; but in early July, when pairs of adults are still feeding young, mixed flocks begin to form. Marbled murrelets feed during the day and at night.
Marbled murrelets and humans
The marbled murrelet is considered globally endangered, with some evidence of decline across its range over the last few decades. The biggest threat to the marbled murrelet was long considered to be loss of nesting habitat (old-growth and mature forests) to logging. Additional factors including high predation rates due to human disturbances and climate-driven changes in ocean conditions are also considered important now.
Scientists at Redwood National Park have established a connection between human presence in marbled murrelet territory and corvid predation of marbled murrelet chicks. Corvid populations, such as Steller's jays, crows, and ravens, are expanding into old-growth forests. Lured by food scraps left by campers and hikers, with increased access aggravated by the patchwork forests created by industrial logging, corvids more frequently discover marbled murrelet nests in areas where these predator species were not previously found.
The populations in Washington, Oregon and California were listed as threatened in 1992 by the U.S. Fish and Wildlife Service due to concerns about loss of nesting habitat, entanglement in fishing gear and oil spills. The Canadian population was declared "nationally threatened" in 1990. The status of Alaskan populations are currently under review. The species became a flagship species in efforts to prevent the logging of old-growth forests along the Pacific coast from California to Alaska.
- BirdLife International (2012). "Brachyramphus marmoratus". IUCN Red List of Threatened Species. Version 2013.2. International Union for Conservation of Nature. Retrieved 26 November 2013.
- Marshall, David B.year= 1988. "Status of the marbled murrelet in North America: with special emphasis on populations in California, Oregon, and Washington". Biological Report (Washington, DC: U.S. Department of the Interior, Fish and Wildlife Service) 88 (30).
- "Determination of threatened status for the Washington, Oregon, and California population of the marbled murrelet". Oregon Birds 18 (4): 120–121. 1992.
- Paton, Peter W. C.; Ralph, C. John (1990). "Distribution of the marbled murrelet at inland sites in California". Northwestern Naturalist 71 (3): 72–84. doi:10.2307/3536775.
- Marshall, David B. (1989). The marbled murrelet. Audubon Wildlife Report, pp. 435–455
- Carter, Harry R.; Sealy, Spencer G. (1986). "Year-round use of coastal lakes by marbled murrelets". Condor 88 (4): 473–477. doi:10.2307/1368273. JSTOR 1368273.
- Singer, Steven W.; Naslund, Nancy L.; Singer, Stephanie A.; Ralph, C. John (1991). "Discovery and observations of two tree nests of the marbled murrelet". Condor 93 (2): 330–339. doi:10.2307/1368948. JSTOR 1368948.
- Marshall, David B. (1988). "The marbled murrelet joins the old-growth forest conflict". American Birds 42 (2): 202–212.
- Sealy, Spencer G. (1975). "Feeding ecology of the ancient and marbled murrelets near Langara Island, British Columbia". Canadian Journal of Zoology 53 (4): 418–433. doi:10.1139/z75-055.
- Vanderkist BA, Xiao-Hua Xue, Griffiths R, Martin K, Beauchamp W, Williams TD (1999). "Evidence of male-bias in capture samples of Marbled Murrelets from genetic studies in British Columbia". Condor 101 (2): 398–402. doi:10.2307/1370004. JSTOR 1370004.
- "National Geographic" Field Guide to the Birds of North America ISBN 0-7922-6877-6
- Seabirds, an Identification Guide by Peter Harrison, (1983) ISBN 0-7470-1410-8
- Handbook of the Birds of the World Vol 3, Josep del Hoyo editor, ISBN 84-87334-20-2
- "National Audubon Society" The Sibley Guide to Birds, by David Allen Sibley, ISBN 0-679-45122-6
- Rare Bird: Pursuing the Mystery of the Marbled Murrelet, by Maria Mudd-Ruth, ISBN 1-5948-5835-7
Names and Taxonomy
Comments: Tree- and ground-nesting populations exhibit no morphological divergence and little genetic divergence (Pitocchelli et al. 1995).
Populations on Asian and North American sides of Beringia exhibit mtDNA differentiation consistent with species-level distinctness (Zink et al. 1995); because sample sizes were small, Zink et al. did not recommend a formal taxonomic change. However, the (Asian) long-billed murrelet (B. perdix) was subsequently split from the American B. marmoratus (Friesen et al. 1996, AOU 1997).
Friesen et al. (1996) examined variation in the mitochondrial cytochrome b gene and in 39 allozyme loci for North American and Asian (then B. m. perdix) marbled murrelets and Kittlitz's murrelet (B. brevirostris) and found significant genetic variation among marbled murrelet populations from different sites within North America.
Genetic data presented by Piatt et al. (2007) indicate that the marbled murrelet is represented by three populations, comprising birds in (1) the central and western Aleutian Islands, (2) central California, and (3) the center of the range from the eastern Aleutians to northern California.
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