North Carolina researchers found vertebrate remains in 4.5 percent of the open bottles they found on roadsides. The researchers recovered the remains of 553 small mammals, including five species of shrew and six species of rodent. They suggest that such an examination of roadside trash can be a way of surveying shrews without causing additional deaths in pit falls or snap traps. It’s also pretty good testament to the benefits of bottle refund laws.

According to the authors’ citations, the idea of using discarded bottles to survey the abundance of shrews goes back to at least 1966.

The study appeared in Southeastern Naturalist. Read more.