Roadkill and Rodenticides

What on earth do these two things have in common? Both obviously involve dead animals. But roadkill are killed directly by vehicles on roads. Rodenticides also directly kill rodents (such as rats in homes or gophers on lawns when they eat the rodenticide) because the main ingredient is an anticoagulant, which prevents blood from clotting and eventually causes the animal to die from internal bleeding. However, rodenticides can also indirectly kill or harm other animals, such as bobcats or hawks, which can become poisoned when they eat rodents that have eaten rodenticide.

Researchers at UCLA and the Santa Monica Mountains National Recreation Area are studying a possible link between indirect rodenticide poisoning of bobcats and a disease called mange. They have noticed that bobcats that have died with mange have all had concentrations of anticoagulant compounds in their liver. Please check out www.urbancarnivores.com to learn more about the study and alternatives to rodenticides. The Habitat Authority has agreed to assist in this research effort by collecting tissue samples from dead bobcats. The tissue is sent to UCLA, where the researchers determine whether the bobcat has mange and/or whether it has traces of anticoagulants in its system (by testing the liver).

Last week, two roadkill bobcats were found along Colima Road within days of each other in almost the same location, and samples were collected for the UCLA study. In addition, genetic material from these samples will also be shared with the U.S. Geological Survey, which is conducting a regional study of large mammals in southern California to determine dispersal patterns. So, hopefully these bobcats will not have died in vain. It is possible that they can be used by scientists to determine whether anticoagulant rodenticides cause mange in bobcats. It is also possible that they can be used by scientists to determine where our bobcats originally dispersed from, and how they are related to other bobcats in southern California. In the meantime, the Habitat Authority is studying wildlife movement across Colima Road in an effort to reduce roadkills over time, helping to maintain habitat connectivity throughout the Puente-Chino Hills Wildlife Corridor.

You can also help by avoiding the use of rodenticides, and by reporting any sick, injured or roadkill bobcats to the Habitat Authority by contacting the Ecologist at 562-201-2062 or slucas@habitatauthority.org.