This is an archived article and the information in the article may be outdated. Please look at the time stamp on the story to see when it was last updated.

ST. LOUIS – State wildlife authorities have finally determined the cause of death for dozens of crows that were recently found dead in Downtown St. Louis and elsewhere in the metropolitan area.

As many as 36 dead crows were found outside the Thomas F. Eagleton U.S. Courthouse in early February. Another 50 dead crows were reported at Creve Coeur Lake around the same time.

The Missouri Department of Conservation (MDC) did not find any obvious signs of trauma. Preliminary testing of the dead crows did not yield an immediate answer.

Five of the birds taken from the federal courthouse were sent to Southwestern Cooperative Wildlife Disease Study (SCWDS) College of Veterinary Medicine at the University of Georgia in Athens. According to the MDC, the examinations included thorough necropsies and pathogen screening.

As a result of those tests, the final diagnosis is that the birds died from a avian reovirus infection. Crows, a member of the Corvidae family, develop a peculiar type of ARV infection called corvid orthoreovirus.

The virus is spread through fecal-oral transmission, which happens when crowd gather in tight spaces for winter roosting. Health officials said the virus causes severe damage and even hemorrhaging to internal organs, most notably the intestines, leading to rapid death. This is known as “winter mortality” among ornithologists.

According to the MDC, avian reoviruses do not pose a threat to human beings or other mammals.