U.S. Army Corps of Engineers is seeking public comments on its recently
released draft environmental assessment of Caspian tern habitat reduction on
East Sand Island in the Columbia River estuary near Chinook, Wash.
Corps proposes to reduce the Caspian tern nesting area on East Sand Island from
1.58 to 1.08 acres to decrease the number of nesting pairs on the island and,
as a result, reduce tern predation on passing juvenile salmon and steelhead
that are listed under the federal Endangered Species.
draft EA assesses potential impact on birds, fish and other ecosystem
components of a reduction in available habitat and of a no action alternative.
Comments received by Feb. 21 will be assessed and a final EA produced over the
course of the winter.
is hoped the National Environmental Policy Act process can be completed before
the migratory birds arrive this spring to nest, said Corps project manager
island has in recent years been home to what is believed to be the largest
colony of nesting Caspian terns in the world.
desired reduction in nesting pairs is in response to unexpectedly high nesting
density exhibited by terns at the colony.
draft environmental assessment for the proposed activity is available for
public review and comment on the Corps’ Portland District website at http://www.nwp.usace.army.mil/Media/Announcements.aspx.
or comments regarding the draft EA should be directed to Steve Helm by phone at
503-808-4778 or email at Steve.R.Helm@usace.army.mil. Comments can also be
submitted by mail to District Engineer, Portland District, U.S. Army Corps of
Engineers, Attn: CENWP-PM-E/Steve Helm, P.O. Box 2946, Portland, OR 97208-2946.
more information about the Caspian Tern Management Plan, visit http://www.birdresearchnw.org/Project-Info/Project-Background/Caspian-Terns/Caspian-Tern-Management-Plan/default.aspx.
tern management plan completed in 2005 called for the relocation of 60 percent
of the East Sand Island colony population to specially constructed habitat
(islands) in Oregon, California, and Washington. Reduction of habitat on East
Sand Island would be contingent upon creation of the new islands at an area
ratio of 2:1.
Caspian terns nested on an average of 4.4 acres from 2001 to 2004 on East Sand
Island (range from 3.9 to 4.7 acres), approximately 6-7 acres of new suitable
habitat would need to be created to reduce the East Sand Island habitat from
between 1 to 1.5 acres.
acreage on East Sand Island was selected because it was assumed it would be
adequate to reduce the number of breeding pairs down to a range of 2,500-3,125
and that a smaller Caspian tern colony on East Sand Island would achieve an
overall increase in salmonid population growth rates.
constructed by the Corps to date all are located east of the Cascade Range in
southern Oregon and northern California except for Fern Ridge which is located
in the southern Willamette Valley in Oregon.
proposed action would address actions called for in the 2008/2010 biological
opinion for the Federal Columbia River Power System. The BiOp describes actions
NOAA Fisheries feel are necessary to
avoid jeopardizing the survival of list salmon and steelhead species.
biological opinion requires implementation of the 2005 Caspian Tern Management
Plan and evaluation of the effectiveness of the plan. The proposed action is
considered adaptive management toward meeting the goals of the opinion and
plan, specifically with respect to number of nesting pairs of Caspian terns at
the East Sand Island colony.
habitat reductions to date have not achieved the desired result so far.
amount of nesting habitat available to Caspian terns on East Sand Island has
declined since 2006 from about 6.5 acres to the current 1.58 acres,” the draft
EA says. “Year 2013 marked the third year that Caspian tern habitat was managed
between 1.58 to 2.0 acres.
reduction was expected to result in 3,125-4,375 nesting pairs (ROD). Despite
incremental reductions in the amount of nesting habitat, numbers of nesting
pairs and amount of predation on juvenile salmonids have remained fairly
2013, at 1.58 acres of nesting habitat on East Sand Island, the number of
nesting pairs was near 7,600 and predation on juvenile salmon was near 4.7
million (Roby et. al. 2013). Neither the FCRPS BiOp objectives for juvenile
salmon survival nor the purpose and need of the EIS/ROD have been met. This
indicates that additional actions are needed,” the draft EIS said.
density of Caspian terns nesting on East Sand Island in 2013 was approximately
1.2 nests per square meter resulting in approximately 7,600 nests, the highest
density ever observed in the Columbia River Estuary,” the draft EA says. “If
nesting occurs at this density in 2014 over 1.08 acres, approximately 5,200
nests would result. This is approximately 66 percent more pairs than the high
end of the range identified in the 2005 environmental impact state for the
management plan of 3,125.
in nesting area on East Sand Island is expected to result in movement in future
years of some terns that would have returned to East Sand Island,” the draft
says. “In 2013, approximately 680 Caspian terns moved from East Sand Island to
some of the constructed inland sites, including Summer Lake, Malheur Lake,
Crump Lake, Sheepy Lake, and Tule Lake.”
more background, see CBB, Jan. 3, 2014, “East Sand Cormorant Colony Increasing;
Estuary’s Single Most Significant Source Of Smolt Mortality” http://www.cbbulletin.com/429387.aspx