(e) = estimate; * = morbidity and mortality

National Wildlife Health Center (NW); University of Illinois (UIL); Illinois Department of Conservation (IL); Rose Lake Wildlife Disease Center - Michigan (RL); Minnesota Department of Natural Resources (MN); Tri-State Bird Rescue & Research Inc. - Newark, Delaware (TS); Wisconsin Department of Natural Resources (WI); Southeastern Cooperative Wildlife Disease Study (SC); Alberta Natural Resources Service (ALB); California Department of Fish and Game - Wildlife Investigations Laboratory (CFG); Idaho Department of Fish and Game - Wildlife Health Laboratory (ID).

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.

Quarterly Mortality Reports

The following highlights wildlife mortality reported to the National Wildlife Health Center (NWHC) from July to September 1995. Seventy two epizootics were reported this quarter; botulism accounted for 63% with losses of more than 249,000 birds.

The Canadian Province of Alberta's Natural Resource Service reported that an estimated 200,000 ducks, shorebirds, raptors, herons and gulls, died from botulism type C on Pakowki Lake (native for "bad water") in southeast Alberta. Botulism caused the death of 31,000 waterfowl on this shallow lake in 1994. This is the largest reported loss of waterfowl in Alberta. It is speculated that blue-green algae poisoning may have been a contributing factor. Despite regular carcass pickup, mortality remained very high (5,000 birds/day) throughout August. A task force is being set up to examine options for management to attempt to deter such losses in future years.

In late July, NWHC received a report of gull mortality on Lake Sakakawea in North Dakota along the shore of a recreational area. Over 200 sick or dead gulls were collected around a boat ramp, fish cleaning station and picnic area. Clinical signs included lethargy, hunched stance, droopy wings and crusty eyes. Chlamydiosis was suspected in the gulls because an outbreak of chlamydiosis occurred in 1986 in gulls nesting on islands in this lake. Two of thirteen carcasses necropsied at NWHC had gross lesions suggestive of chlamydiosis, however, Chlamydia was not isolated by the USDA, National Veterinary Services Laboratory. Salmonellosis and botulism type C were diagnosed in two gulls. Approximately 280 carcasses were collected and incinerated using precautions to reduce the potential of exposure to chlamydia, a human pathogen.

The California Department of Fish and Game, Wildlife Investigation Laboratory reported mortality in desert bighorn sheep in the Old Dad Mountains, San Bernardino County, California. Twenty five sheep were found dead in the vicinity of a guzzler (a water catchment system for the sheep) and thirteen decomposing lambs were found inside the water tank. Type C botulism toxin was detected in the heart blood of the one sheep suitable for necropsy. Type C toxin was also detected in fly larvae collected from dead lambs inside the tank, although all water samples were negative. Investigators speculate that Clostridium botulinum toxin was produced in the lambs that drowned. Toxin present in either the water or fly larvae was then consumed by adult sheep using the guzzler. This is the largest documented mortality event in desert bighorn sheep and the first report of type C botulism in this species.

Steatitis was confirmed in immature great blue and black-crowned night herons that died between April and September, 1995 in Los Angeles and Orange Counties, California. Despite extensive field investigations by the US Fish and Wildlife Environmental Contaminants personnel and personnel from the Long Beach Naval Station, the etiology of this disease remains unknown. The cause of steatitis diagnosed in herons submitted from Point Loma, California in 1993 and 1994 also remains a mystery.

In mid-July 1995, a research scientist from NWHC traveled to Banks Island, Northwest Territories, Canada as part of an ongoing avian cholera project. Collaborating Saskatchewan graduate students on site reported that an estimated 15,000 snow geese and a few jaegars, cranes and gulls died between June 15 and July 5. Research personnel submitted bones of decomposed geese to NWHC. Pasteurella multocida, serotype 1, was isolated from 12/40 bone marrow samples.

Tri-State Bird Rescue and Research reported mortality associated with a spill of approximately 500 barrels of a relatively light, highly paraffinic crude oil, at a dock in Westville, New Jersey. Of the 65 oiled birds collected and treated, only five died from oil exposure. Successful treatment of oiled birds was due to the type of oil spilled and rapid response by Tri-state, the owners of the dock, the US Fish and Wildlife Service and concerned citizens.

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.