(e) = estimate; * = morbidity and mortality
National Wildlife Health Center (NW); Southeastern Cooperative Wildlife
Disease Study (SC); California Department of Fish and Game - Wildlife Investigations
Laboratory (CA); Florida Marine Research Institute (FL); New York State
Department of Environmental Conservation (NY).
Written and compiled by Gregory Kidd, NWHC. The Quarterly Wildlife Mortality Report is available at
http://www.nwhc.usgs.gov. To report mortality or receive information about this report,
contact the above NWHC staff, e-mail: kathy_converse@usgs.gov., or for Hawaiian Islands
contact Thierry Work. Phone: (608) 270-2400, FAX: (608) 270-2415 or write USGS National
Wildlife Health Center, 6006 Schroeder Road, Madison, WI 53711.
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The following
highlights wildlife mortality and morbidity events reported to the
National Wildlife Health Research Center (NWHC) from January through
March, 1996. For ease of agency reporting, the table will be ordered
by state rather than flyway or region.
Avian cholera
was the predominant disease again this winter, accounting for all
six die-offs in California. Salton Sea National Wildlife Refuge
(NWR), a past site of avian cholera die-offs, reported that mortality
was primarily in ruddy ducks using an area north of the Alamo River.
Humbolt Bay NWR, on the coast of northern California, reported that
at least 930 of 1,500 coots on the refuge died of avian cholera.
Fortunately, only a few of the estimated 10,000 ducks present were
affected. There were two distinct peaks of avian cholera mortality
at the Lower Klamath NWR in northern California. In early December,
avian cholera mortality occurred at low levels throughout the refuge
in several species of ducks. As duck mortality subsided in early
January, mortality began in swans. Necropsy examination of tundra
swans and a few trumpeter swans that were initially suspected to
have died from lead poisoning, confirmed avian cholera as the cause
of death. Based on past history, refuge staff suspect that some
of the swans did die of lead poisoning.
Near Kearney,
Nebraska, in the Rainwater Basin, 6,170 snow geese, 1,096 northern
pintails and 1,561 other ducks and geese were collected on two areas
where avian cholera has occurred in the past. At this site, an estimated
one million snow geese were crowded into limited open water creating
ideal conditions for the transmission of avian cholera.
Scientists
from several agencies, headed up by the Florida Marine Research
Institute in the Florida Department of Environmental Protection,
are seeking clues to the cause of death for 155 manatees found between
Englewood and Marco Island, Florida. Their investigation includes
evaluation for a biotoxin associated with red tide occurring in
the mortality area, infectious disease agents or other toxins.
Storm related
trauma was reported in several species following a blizzard that
struck the midwest in late March. A rainstorm that quickly changed
into a snowstorm with winds in excess of 60 mph contributed to the
death of 2,000 sandhill cranes in Nebraska's Rainwater Basin, 7,000
coots and ducks in northern Iowa and 9 Canada geese in Hustisford,
Wisconsin. It is speculated that high winds and poor visibility
may have caused birds to fly into powerlines, trees and other objects
causing their death. There were also unconfirmed reports of storm
related mortality of waterbirds and migrating passerines in surrounding
states.
The New York
State Department of Environmental Conservation (NYDEC) reported
several cases of diazinon poisoning that occurred last year. All
avian mortality was thought to be inadvertent and associated with
the approved application of pesticides. The NYDEC also reported
a suspected intentional misuse of carbofuran at a cattle feedlot
that resulted in the death of three species of passerines.
The J.B. Hansen
NWR, on the Oregon-Washington border, reported mortality in one
of four subpopulations of endangered Columbian white-tailed deer.
Higher than expected mortality occurred on Tenasillahee Island where
deer populations have been increasing. Necropsies performed in the
field revealed that most deer were emaciated with no body fat reserves
and reduced muscle mass and light to moderate parasite loads. One
contributing factor to this emaciation is increasing demands on
food resources on the island caused by increasing numbers of migrating
waterfowl during winter and an increasing nutria population.
Conjunctivitis,
assumed to be caused by a mycoplasmal organism, continues to cause
illness in house finches. New observations of conjunctivitis in
house finches in Indiana, Illinois, Michigan, Wisconsin and Missouri
indicate the disease is slowly spreading westward. In addition to
house finches, Maryland and Virginia have reported conjunctivitis
in goldfinches and purple finches. Investigation continues into
the spread of this disease and the impact on bird populations.
For additional information please contact Dr. Scott Wright,
USGS National Wildlife Health Center - Disease Investigations Branch Chief, at 608-270-2460 or
Paul Slota, USGS National Wildlife Health Center - Support Services
Branch Chief at 608-270-2420.
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