The 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. (http://www.nwp.usace.army.mil/Media/Announcements/tabid/1887/Article/21181/draft-ea-caspian-tern-nesting-habitat-reduction-east-sand-island.aspx
The 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.
The 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
It is hoped the National
Environmental Policy Act process can be completed before
the migratory birds arrive this spring to nest, said
Corps project manager Sondra Ruckwardt.
The island has in recent
years been home to what is believed to be the largest
colony of nesting Caspian terns in the world.
The desired reduction in
nesting pairs is in response to unexpectedly high
nesting density exhibited by terns at the colony.
The draft environmental
assessment for the proposed activity is available for
public review and comment on the Corps’ Portland
District website athttp://www.nwp.usace.army.mil/Media/Announcements.aspx.
Questions 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.
For 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.
A 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.
Because 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.
The 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.
Islands 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.
The 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
This 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.
The habitat reductions to
date have not achieved the desired result so far.
“The 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.
“This 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
“In 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.
“The 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.
“Reduction 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.”
For more background, see
CBB, Jan. 3, 2014, “East Sand Cormorant Colony
Increasing; Estuary’s Single Most Significant Source Of