Land Stewardship and Environmental Contaminants

Science Center Objects

Department of Interior manages millions of acres on behalf of the American people. The need to manage these natural resources can include activities such as pest and weed control, which may involve the application of chemicals.  Our research helps land managers know the potential hazards of these chemicals and identifies any possible actions to reduce unwanted effects on wildlife.

The Wyoming prairie near Oregon Buttes.

The Wyoming prairie near Oregon Buttes.  (Public domain.)

Characterization of Avian Hazards Following Chlorophacinone Use for Prairie Dog Control

Black-tailed prairie dogs are considered a keystone species for the prairie habitat. Many avian species are associated with black-tailed prairie dogs (Cynomys ludovicianus) in winter.  Raptors feed on prairie dogs and non-raptor avian species forage within prairie dog colonies.  However prairie dogs are also considered agricultural pests. The first generation anticoagulant rodenticide Rozol Prairie Dog Bait (chlorophacinone, active ingredient) is registered for control of prairie dogs during winter. Information is needed to determine if operational applications of Rozol at prairie dog colonies result in adverse effects to birds and other non-target wildlife.



American Kestrel (Falco sparverius)

American Kestrel, Falco sparverius (Public domain.)






Hazard, Risk and Physiologically-based Pharmacokinetic Model for Anticoagulant Rodenticides in Kestrels and Owls

Anticoagulant rodenticides have been identified as being hazardous to predatory and scavenging birds on a global scale. Restrictions on the sale, distribution and packaging of some second generation anticoagulant rodenticides (e.g., brodifacoum, difethialone, bromadiolone and difenacoum) have been instituted by the US EPA, and will likely result in expanded use of first-generation anticoagulant rodenticides (e.g., chlorophacinone, diphacinone). The risk posed by anticoagulant rodenticides to wildlife is inadequately characterized, and toxicological data are needed to better evaluate the threat of these compounds non-target organisms.




Vultures unintentionally ingested diclofenac when scavenging livestock treated shortly before death.

Diclofenac appears to have been the principal cause of a severe population crash of the Griffon vulture, Gyps fulvus, in India and Pakistan. (Public domain.)




Toxicity of the Non-Steroidal Anti-Inflammatory Drug Diclofenac

Diclofenac is a non-steroidal anti-inflammatory drug that has been used by veterinarians for the treatment of inflammation, fever and pain in domestic livestock. This drug appears to have been the principal cause of a severe population crash of vultures of the genus Gyps in India and Pakistan. Vultures unintentionally ingested diclofenac when scavenging livestock treated shortly before death. This is perhaps the only well-documented instance of a veterinary drug resulting in an adverse population-level effect in non-target free-ranging birds. Diclofenac is registered for veterinary use in many Western hemisphere countries (e.g., Chile, Argentina, Peru, Ecuador, and provisional use in the United States), and there is potential for non-target exposure of birds of prey, including endangered California condors (Gymnogyps californianus) in the western U.S.