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Friday, June 1, 2012

Marbled Murrelets: An Old Growth-Dependent Species in Danger

 I just finished my undergraduate thesis, Marbled Murrelets: Mysteries & Management, on the political and economic challenges of preserving marbled murrelets. As a student at the University of Washington, it was a great opportunity for my course work to connect with my work as the membership assistant at Washington Wild.

Marbled Murrelet
The marbled murrelet is a robin-sized seabird native to the Pacific Coast of the United States and Canada. Its habit of feeding in the ocean but nesting in old-growth forests makes it one of the most unique species in our region. It also puts the species at great risk. Though about 220,000 individuals live in Alaska, their population has declined by as much as 50% since the 1980s.

Old-growth forests

Marbled murrelet populations in California, Oregon and Washington were listed as threatened (i.e., “likely to become endangered in the foreseeable future”) on the Endangered Species Act in 1992. They have been known to nest in old growth forests within Olympic National Park, Olympic National Forest, and the San Juan Islands. Unfortunately, marbled murrelet populations continue to fall 4-6% annually in our region. Although surveys in the 1930s estimated their population to be in the hundreds of thousands south of Canada, currently only 16,700 individuals survive in California, Oregon and Washington.

The two most important reasons for marbled murrelet decline are habitat loss and increased predation. Both are results of human activity. Logging still destroys a significant amount of old growth forest each year, although it has been significantly curtailed since the 1980s. According to the Forest Service, more than 400,000 acres of old growth trees were logged in the past decade.

However, marbled murrelets have been declining faster than old growth, indicating that other factors also play a role. The most important of these is increased predation, especially by corvids (jays, crows, and ravens). While these birds do not usually venture into old growth, they will follow campers and hikers into these areas if they provide food. Once in old growth, they spot helpless murrelet chicks and eat them. Corvids also find chicks when murrelets nest near the edges of old growth, as might be created when the trees around an old growth stand are logged. Combined with habitat loss, predation makes it almost impossible for marbled murrelets to reproduce.

Marbled murrelets need to be protected in our area. Though some cite their relatively large population in Alaska as a reason to remove the marbled murrelet from the ESA for its California to Washington range, biologists have identified the unique ecological niche the bird occupies as an important reason to work to preserve it. Additionally, there appear to be several subspecies of marbled murrelet in our region. This indicates the marbled murrelets in one area might not be able to recolonize an area they were forced to abandon even if it again became healthy habitat because murrelets need specific adaptations for each area. The population as a whole might not be able to recover if genetic diversity was lost by regional extinctions.

Finally, we’ve only begun to understand the mysteries of the marbled murrelet; for example, humans only discovered its nest in 1974. To lose a creature we know so little about would be a tragedy. As Edward O. Wilson says, “We should preserve every scrap of biodiversity as priceless while we learn to use it and come to understand what it means to humanity.”

Washington Wild’s efforts to protect old growth forests as wilderness also protect marbled murrelet’s habitat. Most of the marbled murrelets in our state are clustered around the Olympic Peninsula. As a founding member of the Wild Olympics Campaign, Washington Wild works with other organizations to protect low-elevation forest lands as Wilderness. Aside from offering world-class recreation opportunities and providing clean water, these forests are the most important to the continued survival of marbled murrelets in the state. In order to remain productive homes for marbled murrelets, these lands need to be permanently preserved in their natural state. To read more about the Wild Olympics Campaign and sign the petition, please click here. With your support, we can ensure marbled murrelets can call the Olympic Peninsula home for decades to come!

 Cat Moore is Washington Wild’s membership assistant. She will be graduating from the University of Washington with a Bachelors in Political Science and Economics next week. When not in the office, you can find Cat studying for the LSAT, playing in the woods, or drinking decaf lattes. 

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