East Sand Island Cormorants in Trouble
East Sand Island’s double-crested cormorant colony has grown to a record size of approximately 14,900 nesting pairs in 2013 (over 40 percent of the western population). This single colony is considered the largest in western North America; it’s likely the largest breeding colony in North America.
The Corps has been conducting research studying the impact of avian predation on juvenile salmonids in the Columbia River Estuary since 1997. The research on East Sand Island contributes to understanding the impact cormorants have on juvenile salmonids migrating out to the ocean.
In 2008, the Corps began to investigate certain non-lethal methods to dissuade double-crested cormorants from nesting in specific locations on East Sand Island. Methods tested to date include hazing with lights, reducing nesting habitat, and using human presence to flush double-crested cormorants off potential nesting sites.
In 2011, the studies focused on reducing the amount of available nesting habitat for double-crested cormorants, which is approximately 11 acres on the western portion of the island and tracking dispersal of radio and satellite tagged individual double-crested cormorants. Habitat reduction was primarily accomplished by installing barrier fences and using human hazers to flush birds from the non-designated nesting area.
In 2013, double-crested cormorants were restricted to 4.4 acres. 83 adult double-crested cormorants were marked with satellite transmitters and several hundred adults were banded with leg bands to provide information about where double-crested cormorants would move during the dissuasion efforts. In spite of a 70% reduction in available nesting habitat, the colony grew to 14,900 pairs. Near-term dispersal locations of radio- and satellite-tagged double-crested cormorants during the 2011-2013 breeding seasons were generally to four main areas identified in geographic proximity to East Sand Island:
Columbia River Estuary (defined as tidally influenced areas near Bonneville Dam);
Outer Washington coast (Willapa Bay and Grays Harbor)
Puget Sound; and
Northern Salish Sea (San Juan Islands, Strait of Georgia, Vancouver, B.C. (BRNW 2014).
The U.S. Army Corps of Engineers has prepared a draft Environmental Impact Statement and management plan to reduce predation of juvenile salmon and steelhead by double-crested cormorants in the Columbia River Estuary. In the past 15 years, double-crested cormorants on East Sand Island consumed approximately 11 million juvenile salmon and steelhead per year. The Corps is working with its cooperating agencies, the U.S. Fish and Wildlife Service, the U.S. Department of Agriculture’s Animal and Plant Health Inspection Service, the Oregon Department of Fish and Wildlife and the Washington Department of Fish and Wildlife to develop the EIS.
The Corps knows managing double-crested cormorant predation could cause significant impacts to the western population of double-crested cormorants. Therefore we must analyze those impacts and evaluate them when making a decision. It is important to note that we are not taking any action at this time, except to request comments on our draft EIS and management plan. Only after a final EIS is completed and a Record of Decision is signed later this year would the Corps begin to implement the preferred alternative.
Several of these areas, the Columbia River Estuary and outer Washington coast, have had the highest levels of use by double-crested cormorants during dissuasion research in 2012 and 2013. There were no confirmed detections of radio- or satellite-tagged double-crested cormorants at inland sites east of The Dalles Dam or coastal sites south of Cannon Beach, Ore.
JD: These birds have been a man-made problem for way too long and it’s about time we used a man-made solution. Human impact is the only reason those birds are here in the first place and now that they’ve become such a massive problem, the bleeding hearts need to step aside and let us clean up our own mess.