Recent Wildlife Disease Case Study from SCWDS Briefs
Birds Falling from the Sky
On the night of December 31, 2010, an estimated 4,000 to 5,000 birds “fell from the sky” as residents celebrated New Year’s Eve in Beebe, Arkansas, about 35 miles northeast of Little Rock. The birds came from a large roost containing an estimated 1.6 million red-winged blackbirds, common grackles, brown-headed cowbirds, and European starlings.
Wildlife biologists with the Arkansas Game and Fish Commission investigated the event and sent dead birds for postmortem examinations to SCWDS, as well as to the Arkansas Livestock and Poultry Commission Diagnostic Laboratory and the U.S. Geological Survey’s National Wildlife Health Center (NWHC). Three days later, approximately 500 dead and dying birds of the same species were found near New Roads, Louisiana. This area is about 40 miles northwest of Baton Rouge and more than 350 miles south of Beebe, Arkansas.
Officials with the Louisiana Department of Wildlife and Fisheries investigated the incident and also submitted dead birds to SCWDS, NWHC, and USDA’s National Veterinary Services Laboratories for postmortem examination. The necropsy results for the Arkansas and Louisiana birds were identical at all of the laboratories and included broken bones, liver fractures, and internal hemorrhages, all consistent with blunt force trauma. There was no evidence of infection, toxicosis, or other underlying disease that might have affected coordination and the ability to fly.
Die-offs of wild birds are not uncommon and may be due to a variety of causes. Blunt force trauma in wild birds typically results from flying into stationary objects, such as trees, buildings, windows, power lines, or towers, but collisions with vehicles also occur. Flight into stationary objects has been very well documented in the Beebe, Arkansas, mortality event.
Some citizens reported hearing loud noises from fireworks at approximately 10:00 PM. Around the same time, Doppler radar detected large flights of birds in the air above and near the roosting area. The species of birds that died in Beebe have poor night vision and do not normally fly after dark. Thus, after being startled from their roost sites, the birds began to collide with houses, trees, parked cars, and mailboxes, some of which were witnessed by local residents....
Source: SCWDS Briefs – A Quarterly Newsletter from the Southeastern Cooperative Wildlife Disease Study College of Veterinary Medicine - January 2011 Issue [pdf]
March 25, 2011
In the Spotlight: Recent Disease Investigation from Southeastern Cooperative Wildlife Disease Study (SCWDS)
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