In North America the Double-crested Cormorant is found from Alaska to Mexico, Maine to Florida, The Gulf coast, up the Mississippi River system , as well as, in the Great lakes and neighboring inland waterways (Hatch & Weseloh, 1999). On TESC campus, the DCCO can be observed on the campus coastline. The far south and the far north ends are the best areas to observe the DCCO. Historically, population sizes and breeding ranges of the DCCO have fluctuated throughout much of North America. Bone samples date back 5,000 years, in the Pacific Northwest, but are not documented nesting in the region until 1927 (Bovy, 2011).

The Double-crested Cormorant can be in both salt water and fresh water environments, and prefers calm to moderate current water. In a report on diving birds in strong tidal areas, both the Brandt’s and the Pelagic Cormorants were commonly found, but the Double-crested was rarely seen in the rough waters (Holm & Burger, 2002). The DCCO is a colony nester and prefers islands and sheltered beach areas to nest (Wild, 2012) (Wires & cuthbert, 2010).

The Double-crested Cormorant commonly feeds on schooling fish in the mid depths (2-8 meters) alone or cooperatively. In the waters of The Evergreen State College, the main source of food is of the herring, smelt, salmon, and perch families (Johnsgard, 1993). Underwater times were observed in both the campus waters as well as those at the Nisqually National Wildlife Refuge (NNWR). The average time underwater was about 28 seconds out of 34 deep-water dives witnessed at both the school’s beach and at the NNWR. An average of only 12 seconds in 5 dives witnessed in the shallow area at the NNWR (Stacey, 2012). DCCO can swallow small fish under water but must bring larger fish to the surface to kill and maneuver before eating (Wild, 2012).

Cormorants in general do not make much noise. When they do make a sound it is similar to the croak of a frog and not that different from the Great-Blue Heron (Stacey, 2012).

Sound of DCCO taking off the water runningMichelettiM_DCCO_takeoffsound_11302012_1257_47-0870_-122-9746

Common behavior seen on the TESC coastline is sitting on a floating devise or on the pilings at the North end. Sometimes they are holding their wings out to dry their feathers after diving or resting until the next feeding time. (Stacey, 2012) Wing spreading behavior occurs in multiple bird species for various reasons.  The most commonly understood benefit of this behavior is that it allows birds to dry out their wings. In some avian species it is also a form of thermoregulation. Cormorants have an insulating layer of plumage that traps air next to their skin, thus, eliminating the need for thermoregulation as only the outer feathers are wetable. The benefit to having feathers that soak up water, unlike most birds who’s feathers have a sort of waterproofing, is that the cormorants can dive deeper and stay under water longer because the weight of the water in their feathers helps eliminates buoyancy.  Staying under water for longer times, however, creates a greater need for cormorants to dry out their wings. The extra weight of water absorbant feathers causes cormorants to fly lower to the water after a dive (Ehrlich, Dobkin, & Wheye, 1988). This wing spreading behavior can take up to 28% of a DCCO’s time budget. Compared to the Pelagic and the Brandt’s that only spend < 4% of their time spreading their wings (Jordon & Paulson, 2009).

On the campus beach, the cormorant’s feeding is mostly a solo endeavor. At the NNWR, the Double-crested Cormorant has been seen feeding in small groups of five to eight birds (Stacey, 2012). During the breeding season, DCCO are more likely to be observed feeding in larger groups in a bimodal pattern, at dawn and mid-afternoon. They require a relatively small abundance of food, even in the breeding season (Coleman, & Richmond, 2007).

Cormorants swim with their feet and not with their wings, they are seasonal monogamous breeders. The DCCO lay between 3-7 eggs (4 is the mean), 28 days to incubate, and 49 days more to fledgling (Johnsgard,1993).

Currently the populations of the Double-crested Cormorant have been on the increase from its most recent decline in the middle part of the 20th century. The decline was due to toxins in the food and water supply like DDT, PCB’s and other chemicals (Sibley, 2009). In the Great Lakes region, efforts to limit the population have involved shooting nesting birds and adding vegetable oil to the eggs to stop them from hatching. The reason for these efforts was to reduce the population of cormorants feeding on regional pen-raised fish (Wild, 2012).

Current population densities make this less of a concern in the Pacific Northwest. Historically the DCCO was viewed as a pest and rigorous efforts were made to eliminate them. It is known that as eary as the 1600s DCCO populations were vast. Those populations were in fact so large that there were concerns over fish populations (Wires and Cuthbert, 2006). In the Columbia River basin migrating smolts, a food source for the DCCO, were listed as threatened or endangered on the U.S. Endangered Species Act (Anderson, Roby, & Collis, 2004). In the Great Lakes, toxic contaminates had nearly eliminated the DCCO by the early 1970s.  However, recovery efforts, as well as an increase in fish abundance allowed the DCCO to significantly recover. In 1972, there were approximately 135 breeding pairs of DCCO in the Great Lakes region. By 2000 those numbers had magnified to 115,000.  It is possible that the expansion of aquaculture and an increase in fish communities may have altered the breeding capacity of the DCCO, leading to the overwhelming population increase. This increase has created human and waterbird competition for fish, and caused damage to the vegetation of their local habitat (Guillaumet, Dorr, Wang, & Doyle, 2014).  The Pacific Northwest has had uneven DCCO populations with site specific growth. The Columbia River estuary at East Sand Island (ESI) experienced a similar population climb as that of the Great Lakes region. In 1989 there were fewer than 100 breeding pairs at the ESI, but in 1991 there were more than 2,000 pairs.  In 2009 there were an estimated 12,087 pairs. The ESI has 40% of the Pacific Northwest breeding DCCO population. Unlike the Great Lakes region, it is believed that this is purely the result of migration. However, as in the Great Lakes region, there is concern for the salmonid populations, which are also listed on the Endangered Species List (Courtot, Roby, Adkins, Lyons, King, & Larsen, 2012).

Credit: U.S. Geological Survey, Department of the Interior, http://www.usgs.govSurvey

This trend map from the Breeding Bird Survey website shows the nationwide increase of the DCCO between 1966-2011.

With the increase in Double-Crested Cormorant populations and the conflict with threatened or endangered fish, management strategies have been put into place to lessen the density of the DCCO population, thereby, lessening the conflict with the fish.  These management strategies could have a far reaching impact on the DCCO, as these management decisions are made on the local level and do not take into account the range-wide implications. The cumulative effects of management are being researched, and more research is needed in this area (Guillaumet, Dorr, Wang, & Doyle, 2014).

Anderson, C. D., Roby, D. D., & Collis, K. (2004). Conservation Implications of the Large Colony of Double-Crested Cormorants on East Sand Island, Columbia River Estuary, Oregon, U.S.A. Waterbirds: The International Journal of Waterbird Biology, 27(2), 155–160.

Bovy, K. M. (2011). Archaeological Evidence for a Double-crested Cormorant Colony in the Pacific Northwest, USA. Waterbirds , 89-95.

Clark, A. C., Kollasch, T. M., & Williamson, D. A. (2006, Autumn). Movements of Double-crested Cormorants Fledged on the Columbia River Estuary. Retrieved October 19, 2012, from Bio One Research Evolved: http://www.bioone.org/doi/full/10.1898/1051-1733%282006%2987%5B150%3AMODCFO%5D2.0.CO%3B2

Coleman, J. T. H., & Richmond, M. E. (2007). Daily Foraging Patterns of Adult Double-Crested Cormorants during the Breeding Season. Waterbirds: The International Journal of Waterbird Biology, 30(2), 189–198.

Courtot, K. N., Roby, D. D., Adkins, J. Y., Lyons, D. E., King, D. T., & Larsen, R. S. (2012). Colony Connectivity of Pacific Coast Double-Crested Cormorants Based on Post-Breeding Dispersal From the Region’s Largest Colony. The Journal of Wildlife Management, 76(7), 1462–1471.

Ehrlich, P. R., Dobkin, D. S., & Wheye, D. (1988). The Birder’s Handbook: A field guide to the natural history of North American birds. United States of America: Simon and Schuster Inc.

Guillaumet, A., Dorr, B. S., Wang, G., & Doyle, T. J. (2014). The cumulative effects of management on the population dynamics of the Double-crested Cormorant Phalacrocorax auritus in the Great Lakes. Ibis, 156(1), 141–152.

Hatch, J. J., & Weseloh, D. V. (1999). Double-crested Cormorant (Phalacrocorax auritus). Retrieved November 16, 2012, from The Birds of North America Online: : http://0-bna.birds.cornell.edu.cals.evergreen.edu/bna/species/441

Holm, K. J., & Burger, A. E. (2002). Foraging Behavior and Resource Partitioning by Diving Birds During Winter in areas of Strong Tidal Currents. Waterbirds , 312-325.

Johnsgard, P. A. (1993). Cormorants, Darters, and Pelicans of the World. Washington DC: Smithsonian Institution Press.

Jordon, M., & Paulson, D. (2009, Spring). Wing-spreading Behavior in Pacific Cormorants. Retrieved October 19, 2012, from BioOne Research Evolved: http://www.bioone.org/doi/full/10.1898/1051-1733-90.1.39

Sibley, D. A. (2003). The Sibley Field Guide to Birds of Western North America. New York: Random House, Inc.

Sibley, D. A. (2009). The Sibley Guide to Bird life and Behavior. New York: Andrew Stewart Publishing Inc.

Stacey, M. S. (2012). Field Notebook Ornithology Fall 2012. Edgewood : none.

Wild, D. (2012). The Double-crested Cormorant (Symbol of Ecological Conflict). Ann Arbor: University of Michigan.

Wires, L. R., & Cuthbert, F. J. (2006). Historic Populations of the Double-Crested Cormorant (Phalacrocorax auritus): Implications for Conservation and Management in the 21st Century. Waterbirds: The International Journal of Waterbird Biology, 29(1), 9–37.

Wires, L. R., & Cuthbert, F. J. (2010). Characteristics of Double-crested Cormorant Colonies in the U.S. Great Lakes Island Landscape. Journal of Great Lakes Research, 232-241.

Michael Stacey is as happy in the woods as on the water, being indoors is fine just give him a good Sci-fi movie to watch. Born and raised in Puget Sound area but Montana could be an option. If you just sit still in the woods or on the beach the wildlife will come to you.

Loba Azul is at home in wild places. Loba is a certified wildlife rehabber and has spent many years following their passion for nature. Loba is the founder of Wolfwild (wolfwild.org), an organization that advocates for captive and wild wolves and wolf dogs.