The term “murder of crows,” which apparently is the collective noun referring to a flock of the birds, could have a quite literal meaning. A new report from USDA researchers indicates that carrion birds such as crows could be responsible for helping distribute prions – the infectious agents in transmissible spongiform encephalopathy (TSE) diseases including chronic wasting disease (CWD), scrapie, and BSE.

The researchers, working at the National Wildlife Research Center in Fort Collins, Colorado, hypothesized that TSE prions could pass intact through the digestive tract of crows. This would suggest crows or other scavenger birds could play a role in the spread of TSE diseases, as their feces potentially could contaminate food sources consumed by mammals, particularly in the case of cervids such as deer and elk, which are susceptible to CWD.

To test their hypotheses, they fed 20 crows mouse tissue infected with a form of mouse-adapted scrapie. Five crows served as a control group and received mouse tissue from uninfected mice.