Brachyramphus marmoratus

The marbled murrelet feeds on fish such as sandlace and herring but feeds on invertebrates during winter (2). They forage singly, in pairs or in feeding flocks of a mix of different species (3). In California, breeding occurs from mid-March to early September, but the season is shorter further north (2). The nest is built on large branches in high elevation forests or on the ground on some islands. Incubation of the yellowish spotted eggs takes around 30 days and the young chicks fledge after a further 28 days (3).

The marbled murrelet is a small, chubby seabird that has a very short neck (3). During the breeding season it has dark brown to blackish upperparts and a white belly and throat that are greatly mottled. During the winter the upperparts become grey, dark marks form on the sides of the breast and a white ring develops around the eye (2). Males and females are similar in appearance and size (4) (3). Juveniles are similar to the adult winter plumage, but with dusky mottling on the underparts (2). Vocalisations include a sharp 'keer' or low 'kee' (3).

W Aleutian Islands and Alaska to central California.

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 [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,
California [16].

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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

AK CA OR WA BC

Brachyramphus marmoratus occurs in the USA and Canada in California, Oregon, Washington, British Columbia, south-east Alaska, Prince William Sound, Kenai Peninsula, Lower Cook Inlet, Barren Islands, Afognak and Kodiak Islands, the Alaska Peninsula and the Aleutians locally to Andreanof and Near Islands⁶. In Alaska (85% of the population), historical estimates place the population at c. 750,000 individuals, though when trend estimates are applied to this figure it gives an estimated 2006 population of c. 270,000 individuals²⁹. The British Columbia population is thought to be in the region of c. 54,000 - 92,500. The greatest historical decreases have been in Washington, Oregon and California, but populations in British Columbia and south-east Alaska are now most threatened¹³. The current annual decline in Washington, Oregon and California is 4-7%²¹, with a c. 70% decrease in Alaska from 1985-2010²⁹, and 40% in parts of British Columbia in 1982-1992¹⁰..

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

Canada

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

Type of Residency: Year-round

United States

Origin: Native

Regularity: Regularly occurring

Currently: Present

Confidence: Confident

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.

Historic Range:
U.S.A. (AK, CA, OR, WA), Canada (B.C.)

Found along the western coast of the USA and Canada in California, Washington, Oregon, British Columbia, Alaska, Prince William Sound, Kenai Peninsula, Lower Cook Inlet, Barren Islands, Afognak and Kodiak Islands, the Alaska Peninsula and the Aleutians (2). Historically, the decline of this species has been most severe in Washington, Oregon and California; at present, however, the worst losses are occurring in British Columbia and Alaska (2).

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."

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).

More info for the term: tree

Marbled murrelets are coastal birds that occur mainly near saltwater
within 1.2 miles (2 km) of shore [16]. 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 [4]. 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
[8].

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 [4]. Marbled murrelets
tend to nest in the oldest trees in the stand [4]. In Oregon, forests
begin to exhibit old-growth characteristics at about 175 to 250 years of
age [17]. 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 [26].
However, Marshall [29] 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 [17]. 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 [4]. 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 [17].
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 [29].

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 [16].

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 [17]. Flocks
of 50 or more birds have been observed near freshwater lakes [8].
Subadults occur at sea throughout the summer. Sealy [30] 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
[8].

More info for the term: tundra

In northern regions where coniferous forests nest sites are unavailable,
marbled murrelets occupy alpine or tundra near the ocean [16]. 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
lawsoniana) [19,22].

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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):

FRES20 Douglas-fir
FRES23 Fir-spruce
FRES24 Hemlock-Sitka spruce
FRES27 Redwood

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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
231 Port-Orford-cedar
232 Redwood
234 Douglas-fir - tanoak - Pacific madrone

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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

Habitat and Ecology

Systems

• Terrestrial
• Freshwater
• Marine

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

Depth range based on 2385 specimens in 1 taxon.
Water temperature and chemistry ranges based on 17 samples.

Environmental ranges
  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

Graphical representation

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.

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).

Found near coastal waters, in bays and on mountains. It nests at high elevations in old growth forest, often at great distances from the coast (3). This species can be found up to 500 meters offshore (2).

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.

Marbled murrelets feed below the water surface on small fish and
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 [16].
Marbled murrelets feed during the day and at night [17].

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.

Steller's jays (Cyanocitta stelleri) and common ravens (Corvus corax)
prey on marbled murrelet eggs and nestlings [26].

Note: For many non-migratory species, occurrences are roughly equivalent to populations.

Estimated Number of Occurrences: 81 to >300

Comments: Total number of occurrences has not been determined using standardized criteria, but likely there are well over one hundred. 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 adult population size is a few hundred thousand, with a few 10,000s in Washington-Oregon-California, 54,000-92,000 in British Columbia, and around 270,000 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).

More info for the term: mesic

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
limbs [16].

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 [31]. 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
[15,31].

Age at sexual maturity - Marbled murrelets do not breed until they are
at least 2 years old [16].

Nesting and brooding - Marbled murrelets nest from mid-April to late
September [16]. Peak activity occurs from mid-June to late July in
California, and the second week of July to mid-August in Oregon [17].
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 [4]. 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 [16]. Fledglings fly directly from the
nest to the ocean [4].

Migration - Some marbled murrelet populations probably migrate south in
fall and north in spring. However, these migration patterns are not
well understood [7].

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).

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).

Average lifespan
Status: wild: 120 months.

Maximum longevity: 7.2 years (wild)

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).

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).

The following is a representative barcode sequence, the centroid of all available sequences for this species.

There are 6 barcode sequences available from BOLD and GenBank.  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.

Download FASTA File

Barcode of Life Data Systems (BOLDS) Stats
Public Records: 6
Specimens with Barcodes: 11
Species With Barcodes: 1

Current Listing Status Summary

Status: Threatened
Date Listed: 10/01/1992
Lead Region:   Pacific Region (Region 1) 
Where Listed: U.S.A. (CA, OR, WA)

Population detail:

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

Canada

Rounded National Status Rank: N3 - Vulnerable

United States

Rounded National Status Rank: N3 - Vulnerable

Information on state-level protected status of the marbled murrelet in the
United States is available at NatureServe.

Threatened [35]

Year Assessed

Assessor/s

Reviewer/s

Contributor/s

Justification

History

• 2008
  Endangered
• 2005
  Endangered
• 2004
  Endangered
• 2000
  Vulnerable
• 1994
  Not Recognized
• 1988
  Not Recognized

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

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 G3G4 was confirmed using NatureServe Rank Calculator Estimator Version 6.11.

Intrinsic Vulnerability: Moderately vulnerable

Comments: Low reproductive rate (1 egg/pair/season); slow recovery rate.

Classified as Endangered (EN) by the IUCN Red List 2007 (1).

Global Short Term Trend: Decline of 50 to >90%

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 (it was not possible to generate a similar estimate for historical population size in British Columbia). 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. In British Columbia, available trend data indicate that murrelet populations there have experienced similar declines. Updating a recent (2002) population estimate for British Columbia, Piatt et al. concluded that there are now between 54,000 and 92,000 murrelets in British Columbia. The rates of decline are within, but at the high end of, a range of rates expected by chance (Piatt et al. 2007). Given that declines were estimated for sites over essentially the entire northern range of the species, there is cause for concern about the species' status.

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).

Population

Population Trend

Degree of Threat: High

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).

Major Threats

In many areas, the old-growth forests in which this murrelet breeds are subject to logging. Declines in areas where logging has not been a problem are thought to be due to a reduction in fish prey (2). Significant mortalities of this species have been caused by the birds becoming caught in gill-nets used in fishing, and by oil spills (2).

The principal factor threatening the persistence of marbled murrelet
over the southern portions of its range is harvesting of old-growth and
mature forests [17]. 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
perpetuation [16,29].

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 [29]. Sealy and Carter [24] 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
[16].

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 [24].

Conservation Actions

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.

Conservation measures taken to date include the protection of some areas supporting this species from future logging. Detailed research has been carried out on this murrelet, and a recovery plan has been produced. Furthermore, 179 km² of Afognak Island has been protected since 1998 by the Exxon Valdex Trustee Council (2). Proposed measures include research, particularly into the feeding ecology of this bird in order to fully understand the threats facing it. It is vital that suitable nesting habitat is protected and that fish stocks in known feeding areas are not severely damaged (2).

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).