Marbled Murrelets & The Robson Bight Ecological Reserve – By Sarein Basi-Primeau

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The Robson Bight Marine Warden Program has been up and running since the beginning of July and we have been keeping busy contacting mariners educating them about the Reserve boundaries, the Be Whale Wise guidelines and the importance of the Reserve. The Robson Bight Ecological Reserve not only provides critical habitat for the red-listed Northern Resident Killer Whales, but is also home to many other endangered and threatened species. One of them is the red-listed marbled murrelet (Brachyramphus marmoratus), which Sarein, one of our volunteers for the summer, talks about in more detail here:

This small seabird is red-listed by the province of British Columbia and the International Union for Conservation (IUCN), and deemed threatened by both the Committee On the Status of Endangered Wildlife in Canada (COSEWIC) and the Species at Risk Act (SARA). This species forages in the Robson Bight’s marine area and nests in the upland forested area of the Tsitika River estuary. The marbled murrelet’s range extends 4,000 kilometres along the coastline from Alaska to California, and up to 75 kilometres inland. They are very difficult to survey, therefore their total population is unknown, but it is estimated to be between 263,000 and 841,000, with at least 50,000 individuals in BC.

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Collecting data on marbled murrelets and their nests is difficult due to the fact that they are highly reclusive, with solitary nests or loosely associated groupings, unlike other seabirds that nest in large colonies. The marbled murrelet relies on old-growth coniferous forests for nesting, where they choose a large tree limb (15-75 centimetres in diameter) hundreds of feet high in the canopy of an old-growth coniferous tree, with small gaps in the tree cover for access. This limb must have a deep moss layer within which they create a depression for their single egg. Incubation of this egg takes about 28 days with both the male and female of a pair sharing this task and the subsequent care of the young. Nesting success is low, mainly due to predation from birds such as ravens, crows, and jays. In addition to dependence on old-growth coniferous forests, marbled murrelets depend on offshore and inshore marine areas for foraging. Their diet consists of small invertebrates such as plankton, and vertebrates such as sandlance, surf smelt, and juvenile herring.

 

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There have been a few documented cases of marbled murrelets nesting on cliff edges, however, they mostly nest in coniferous old-growth forests. Therefore, the greatest threat to the marbled murrelet is the loss of these forests, which are often the focus of commercial activity such as logging. Other threats include entanglement in commercial gill nets when foraging at sea and oil contamination of their marine foraging areas that reduce food availability and coat their plumage with oil. In conclusion, these threats render the marbled murrelet sensitive to disturbance and to having an overall low reproductive rate. Thankfully, action is being taken to increase the marbled murrelet population through groups such as the Marbled Murrelet Recovery Team, who work to increase their knowledge of the species in order to better understand how to protect it through their recovery plan.

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As an already important area for the marbled murrelet, the Robson Bight Ecological Reserve is also home to many other bird species such as bald eagles, peregrine falcons, belted kingfishers, Stellar’s jays, common ravens, northwestern crows, pacific wrens, cedar waxwings, red crossbills; Anna’s and rufous hummingbirds; downy, hairy and pileated woodpeckers; flycatchers, grouse, sandpipers, many species of gulls including Mew, Bonaparte’s and Herring, the threatened northern saw-whet owl and the red-listed northern goshawk.

 

Photo 1: Alaska Department of Fish and Game. Accessed online July 15, 2016: http://www.adfg.alaska.gov/index.cfm?adfg=marbledmurrelet.main

Photo 2: Bill Hill. Accessed online July 15, 2016: http://creagrus.home.montereybay.com/alcids.html

Photograph 3: Kevin Jordan. Accessed online July 15, 2016: http://web.uvic.ca/~mamu/mamu.html

Photograph 4: Peter Halasz. Accessed online July 15, 2016:  https://commons.wikimedia.org/w/index.php?curid=1235700

 

References:

BC Parks. March 2013. The Robson Bight (Michael Bigg) Ecological Reserve: Purpose Statement. Accessed online July 15, 2016: www.env.gov.bc.ca/bcparks/planning/mgmtplns/robsonb/robsonbight_ps.pdf

Government of Canada Species Risk Public Registry. 2016. Marbled Murrelet. Accessed online July 13, 2016: http://www.registrelep-sararegistry.gc.ca/species/speciesDetails_e.cfm?sid=39

Marbled Murrelet Recovery Team. Accessed online July 16, 2016: http://www.sfu.ca/biology/wildberg/bertram/mamurt/index.htm

Sibley, D.A. 2003. The Sibley field guide to birds of Western North America. First Ed. New York: Alfred A. Knopf, Inc.

UVic Seabird & Murrelet Research Group. Accessed online July 15, 2016: http://web.uvic.ca/~mamu/mamu.html

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