VENTURA COUNTY — The Ventura County Public Works Agency (VCPWA) has discovered that hawks and owls may be more effective than rodenticide anticoagulants for controlling rodent damage to dams and levees.. In the Ventura County area, there is heightened awareness of the potential for secondary poisoning when a rodent which ate anticoagulant is consumed by a higher predator. Deceased and sick bobcats, coyotes, and mountain lions in the area have tested positive for anticoagulant residues in their blood.
VCWPA data from its Raptor Study for levee protection indicate that where raptor perches attracted hawks and owls, rodent burrow damage was reduced by about 50 percent when compared to locations with anticoagulant rodenticides in bait stations. The VCPWA study marks the first time any agency has quantified the impact of birds of prey on rodents in public works projects.
As the first study of its kind, the program has garnered substantial positive recognition. Through implementing an environmentally friendly system and promoting the natural lifecycle VCPWA has earned the following accolades:
- Presentation at the United State Society on Dams, National Conference
- OWL Award presented by the Earth Island Institute
- Earth Day Award presented by Ventura County Board of Supervisors
- Environmental Stewardship Award presented by State of California Senator Fran Pavley
- Environmental Project of the Year (Ventura County Chapter) presented by the American Public Works Association
- Environmental Thank You Award from Poison Free Malibu
It is essential for public health and safety that flood control facilities are protected from burrowing rodents. Rodents can cause significant damage and even failure of levees, earth dams and other flood control channels. A ground squirrel tunnel can be 35 feet long, and a single gopher is capable of moving about one ton of earth every year. The Ventura County Board of Supervisors has directed all county agencies to discontinue the use of rodenticides on County property with the exception of several critical flood control facilities where alternatives to control rodents are not available.
“We believe the VCPWA Raptor Pilot Study is the first to quantify the dramatic impact of attracting raptors and finds a natural, chemical-free way to control burrowing rodents,” said Karl Novak, VCPWA Deputy Director of Operations and Maintenance. “We think that comprehensive monitoring and continued expansion of the raptor program will result in cost effective and environmentally safe rodent control throughout our watersheds.”