^A **** = cessation date not available.

^B (e) = estimate, *** = mortality estimate not available.

^C Suspect = diagnosis is not finalized or completed tests were unable to confirm the diagnosis, but field signs and historic patterns indicate the disease; Open = diagnosis is not finalized and tests are on-going; Undetermined = testing is complete or was not pursued and no cause of death was evident; NOS = not otherwise specified.

^D California Animal Health and Food Safety Laboratory Network (CAF), California Fish & Game Disease Laboratory (CFG), Columbia University (CU), Michigan Department of Natural Resources (MI), National Oceanic & Atmospheric Administration (NOA), No diagnostics pursued (NON), USDA National Veterinary Services Laboratories (NVL), USGS National Wildlife Health Center (NW), Oregon State Diagnostic Laboratory (OR), Other (OT), Southeastern Cooperative Wildlife Disease Study (SCW), Sea World (SW), University of Connecticut Wildlife Laboratory (UCT).

Written and compiled by the U.S. Geological Survey National Wildlife Health Center Field Investigations Team members: Anne Ballmann, LeAnn White, Barb Bodenstein, and Jennifer (Buckner) Buckner.

To report mortality or receive information about this report, please contact the USGS National Wildlife Health Center, 6006 Schroeder Road, Madison , WI 53711

For single animal mortality, nationwide, please contact: Jennifer Buckner, USGS National Wildlife Health Center Biologist by phone: (608) 270-2443, fax: (608)-270-2415, or email: jBuckner@usgs.gov

Quarterly Mortality Reports

Thousands of Eared Grebes crash land in southern Utah
Utah Department of Wildlife Resources (UDWR) staff responded to reports of approximately 3,500 Eared grebes found dead or injured the morning of December 13, 2011. UDWR staff suspected the birds had crash landed in parking lots of local businesses and road ways throughout St. George/Cedar City area during snow storms the night before. An estimated 2,000 birds were reported dead and another 1,500 alive. Dead and injured birds had impact related trauma injuries such as broken wings and necks. Other birds were simply stranded and appeared healthy. The affected area was approximately 15 miles wide and 30 miles long. Surviving healthy grebes were captured, evaluated and released into nearby water bodies in southern Utah where they were able to achieve a running start required to take flight. Carcasses submitted to the NWHC for necropsy confirmed blunt trauma. No underlying diseases were identified. The event received national media attention due to its size. Similar events in this area of Utah occurred in 1991 and 1997 involving an estimated 4,500 and 6,700 Eared grebes, respectively.

Pelagic bird mortalities along the Pacific coast of Ventura and Santa Barbara counties (California)
A mortality event involving primarily Western and Clark's grebes was reported along the Pacific coast of Ventura and Santa Barbara counties, California in early November 2011 by the U.S. Fish and Wildlife Service (USFWS), Ventura Fish and Wildlife Office (VFWO), and California Department of Fish and Game Office of Spill Prevention and Response (OSPR). The event may have started in early October, based on admissions to local wildlife rehabilitation facilities at that time. Birds were observed stranded on beaches and struggling to stay upright along the coastal waters of Ventura Harbor. As of March 2012, an estimated 670 pelagic birds and 7 marine mammals have been reported moribund or dead. During November and December, the NWHC received 26 birds representing 8 species for diagnostic evaluation and a field investigation by NWHC staff was conducted in mid-December. Emaciation has been the only consistent finding among all the birds examined. However, non-specific vacuoles (holes) in the white matter of brains in 12 birds also were detected. Infectious diseases such as pathogenic bacteria and viruses have been ruled out. Electron microscopy of brain tissue and contaminant analysis is currently being pursued to better characterize the nature of these brain lesions and cause of mortality. Partners from USFWS, CAFG and wildlife rehabilitation volunteers continue to monitor the area and receive individual bird stranding reports; however, peak mortality had subsided by late December.

Unusual mortality event of Harbor seals along the northeastern Atlantic Coast (Maine, New Hampshire, Massachusetts)
An unusual mortality event (UME) primarily among juvenile Harbor seals (Phoca vitulina) was declared by the National Oceanic and Atmospheric Administration (NOAA) in November 2011 along the northeast Atlantic coast from southern Maine to northern Massachusetts. Peak mortality occurring from early September to mid-October was three times the average annual mortality rate reported for the region. Total mortality was estimated at 163 animals by early December; upper respiratory signs were reported in sick animals. The USGS-National Wildlife Health Center was one of several collaborating laboratories invited by NOAA to participate in the mortality investigation and provided virology support. Common findings reported by partners among the 23 animals examined included good to fair nutritional condition, hemorrhagic interstitial pneumonia, and ulcerative dermatitis. Mixed bacterial pneumonia was thought to be secondary to an underlying respiratory infection. Influenza A virus (subtype H3N8 of avian origin) was isolated from multiple tissues of five seals collected from coastal New Hampshire during peak mortality. The role of avian influenza as the main cause of mortality in the broader geographic area could not be established because of insufficient suitable samples. Test results of seal samples collected late in the mortality event have been negative for influenza viruses. Mortality from influenza A infections have occurred in the past among free-ranging seal populations although this is the first report of the H3N8 subtype. Diagnostic investigations continue on available samples. For more information on the Atlantic coastal event, visit http://www.nmfs.noaa.gov/pr/health/mmume/pinniped_northeast2011.htm.

Trematodiasis continues to cause mortality on the Upper Mississippi River and Lake Winnibigoshish (Minnesota, Wisconsin)
Trematodiasis, caused by the exotic trematodes Sphaeridiotrema globulus, Cyathocotyle bushiensis, and Leyogonimus polyoon, caused the largest number of avian mortalities (>15,000) in the Mississippi Flyway in 2011. The two main sites of mortality, the Upper Mississippi National Wildlife Refuge (Pools 7, 8, and 9) and Lake Winnibigoshish, Minnesota first experienced trematodiasis associated mortality in 2002 and 2007, respectively. Biannual disease monitoring efforts on Pools 7 and 8, conducted by refuge staff since 2002, indicated that the 2011 mortality numbers approached the peak levels reported in 2007. The drivers of variations in annual mortality caused by this disease are not completely understood. Combined spring and fall mortality was approximately 13,800 on Pools 7 and 8 on the Mississippi River and approximately 600 on Lake Winnibigoshish. Mortality on Pool 9 of the Mississippi River was only observed in the fall of 2011 and resulted in approximately 1,000 dead. The two primary species affected by this disease continue to be American coot and Lesser scaup.