Brachyramphus marmoratus

Taxonomy

Assessment Information

Geographic Range

Population

Habitat and Ecology

Threats

Conservation Actions

View Printer Friendly

Taxonomy [top]

Kingdom	Phylum	Class	Order	Family
ANIMALIA	CHORDATA	AVES	CHARADRIIFORMES	ALCIDAE

Scientific Name:

Brachyramphus marmoratus

Species Authority:

(Gmelin, 1789)

Common Name/s:

English

–

Marbled Murrelet

Assessment Information [top]

Red List Category & Criteria:

Endangered A2c+3c+4c ver 3.1

Year Assessed:

2010

Assessor/s:

BirdLife International

Reviewer/s:

Bird, J., Butchart, S. & Calvert, R.

Contributor/s:

Bertram, D. & Kuletz, K.

Justification:
This species is still abundant, but it is treated as Endangered because its population is estimated to have undergone a very rapid reduction over three generations (36 years), owing to a variety of threats. This decline is likely to continue.

History:

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

Geographic Range [top]

Range Description:	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..
Countries:	Native: Canada; United States Vagrant: Mexico
Range Map:	Click here to open the map viewer and explore range.

Population [top]

Population:	Agler et al. (1998).
Population Trend:	Decreasing

Population:

Agler et al. (1998).

Population Trend:

Decreasing

Habitat and Ecology [top]

Habitat and Ecology:	It nests in old-growth trees (up to 60 km inland) and on the ground (sparsely where trees are absent, suboptimal)^{6,11,14,16,19}, with the breeding season stretching between March and September in California, and May and September in Alaska²⁹. Forest areas with multiple canopy layers and high mistletoe abundance are strongly preferred²². Breeding is mid-March to early September in California, but more compressed further north^6,7,8. The diet is sandlance, herring and, in winter, invertebrates⁶. Chicks are generally fed large subadult or adult prey rather than juveniles or larvae²⁹. It feeds in near-shore habitats up to 1.4 km offshore, in sheltered waters, lagoons and sometimes inland lakes^3,4,6,9,27. Daily movements to feeding areas can be up to 250 km²⁰. Radio-marked birds from Redwood Creek in North California moved a maximum average distance of 99 km alongshore, with males travelling further than females, and non-breeding males travelling further than breeding males perhaps in search of mates or nesting habitats. Average home range size was 505 km², again being greater for males than females²⁷. Individuals exhibit plasticity in their foraging behavior, foraging closer to shore and increasing dive rates during nesting²⁸. Marbled Murrelets most often forage in pairs²⁹. Individuals in the northern part of its range may travel south during the non-breeding season, a movement which likely reflects the availability of prey²⁹.
Systems:	Terrestrial; Freshwater; Marine

Habitat and Ecology:

It nests in old-growth trees (up to 60 km inland) and on the ground (sparsely where trees are absent, suboptimal)^{6,11,14,16,19}, with the breeding season stretching between March and September in California, and May and September in Alaska²⁹. Forest areas with multiple canopy layers and high mistletoe abundance are strongly preferred²². Breeding is mid-March to early September in California, but more compressed further north^6,7,8. The diet is sandlance, herring and, in winter, invertebrates⁶. Chicks are generally fed large subadult or adult prey rather than juveniles or larvae²⁹. It feeds in near-shore habitats up to 1.4 km offshore, in sheltered waters, lagoons and sometimes inland lakes^3,4,6,9,27. Daily movements to feeding areas can be up to 250 km²⁰. Radio-marked birds from Redwood Creek in North California moved a maximum average distance of 99 km alongshore, with males travelling further than females, and non-breeding males travelling further than breeding males perhaps in search of mates or nesting habitats. Average home range size was 505 km², again being greater for males than females²⁷. Individuals exhibit plasticity in their foraging behavior, foraging closer to shore and increasing dive rates during nesting²⁸. Marbled Murrelets most often forage in pairs²⁹. Individuals in the northern part of its range may travel south during the non-breeding season, a movement which likely reflects the availability of prey²⁹.

Systems:

Terrestrial; Freshwater; Marine

Threats [top]

Major Threat(s):	Many areas of remaining old-growth forest are slated for logging. Since the collapse of the Pacific sardine fishery, prey quality and abundance has declined, with lower trophic-level prey (e.g. krill) now dominating the pre-breeding diet²³. This has resulted in a lower proportion of individuals reaching breeding condition, and therefore lower population productivity. This factor, combined with high rates of nest predation by corvids, is thought to be the primary cause of recent declines²⁴. Nylon, monofilament gill-nets in shallow waters and oil-spills (e.g. Exxon Valdez and Nestucca) also cause considerable mortality^3,6,12,15.

Major Threat(s):

Many areas of remaining old-growth forest are slated for logging. Since the collapse of the Pacific sardine fishery, prey quality and abundance has declined, with lower trophic-level prey (e.g. krill) now dominating the pre-breeding diet²³. This has resulted in a lower proportion of individuals reaching breeding condition, and therefore lower population productivity. This factor, combined with high rates of nest predation by corvids, is thought to be the primary cause of recent declines²⁴. Nylon, monofilament gill-nets in shallow waters and oil-spills (e.g. Exxon Valdez and Nestucca) also cause considerable mortality^3,6,12,15.

Conservation Actions [top]

Conservation Actions:	Conservation Actions Underway It is Threatened in all range states except Alaska. Detailed conservation recommendations were made in 1995¹⁷. Federal land-use is regulated, areas for management identified, and some temporarily removed from logging¹², 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 Canada there has been extensive research, a (now outdated) Recovery Plan and interim protection for nest-sites¹⁸. The Northwest Forest Plan (2006) is expected to ensure the protection of a large proportion of important habitats in the USA²⁵. In 1998, the Exxon Valdez Trustee Council protected 179 km² of Afognak Island². 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 productivity²⁶Research 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 areas¹⁸. Update the Canadian Recovery Plan¹⁸. Protect nesting habitat¹¹. 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 logging¹¹. List as Threatened in Alaska¹¹.

Conservation Actions:

Conservation Actions Underway
It is Threatened in all range states except Alaska. Detailed conservation recommendations were made in 1995¹⁷. Federal land-use is regulated, areas for management identified, and some temporarily removed from logging¹², 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 Canada there has been extensive research, a (now outdated) Recovery Plan and interim protection for nest-sites¹⁸. The Northwest Forest Plan (2006) is expected to ensure the protection of a large proportion of important habitats in the USA²⁵. In 1998, the Exxon Valdez Trustee Council protected 179 km² of Afognak Island².

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 productivity²⁶Research 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 areas¹⁸. Update the Canadian Recovery Plan¹⁸. Protect nesting habitat¹¹. 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 logging¹¹. List as Threatened in Alaska¹¹.

Citation:	BirdLife International 2010. Brachyramphus marmoratus. In: IUCN 2011. IUCN Red List of Threatened Species. Version 2011.2. <www.iucnredlist.org>. Downloaded on 10 February 2012.
Disclaimer:	To make use of this information, please check the <Terms of Use>.
Feedback:	If you see any errors or have any questions or suggestions on what is shown on this page, please fill in the feedback form so that we can correct or extend the information provided