Look, in the sky! It’s a bird, it’s a pla — actually it is a bird, a raptor, to be to precise, acting sentinel over Ventura County’s many dams and levees with one goal in mind: to prevent rodents from damaging important infrastructure.
On Wednesday, Sept. 12, Karl Novak of the Ventura County Watershed Protection District will present results of a three-year-long project aimed at ridding the county of rodenticides and replacing them with a natural pest deterrent — hawks and owls.
Through a program launched by Ventura County Public Works, rodenticides — poisons aimed at eradicating of rats, mice, ground squirrels, gophers and other burrowing creatures — have been removed, and in some cases replaced by perches and owl boxes to attract predators as a natural method by which to suppress the rodent population, particularly around the Ventura County Watershed Protection District.
The District includes 40 miles of levees, 216 miles of channels and 55 earthen dams, all of which can be damaged or made unsafe by rodent burrows, which can be up to 35 feet long, according to a presentation put together by Karl Novak, deputy director of the Watershed Protection District, and David Torfeh. One gopher, for instance, can displace one ton of soil in a single year, says Novak.
In 2005, secondary rodenticide poisoning of mammals came to the attention of the Board of Supervisors, which directed agencies to avoid using them and to come up with a better solution. The District immediately stopped using bait stations in all areas except dams and levees and created the Integrated Pest Management Program, seeking alternatives.
In 2016, the District began studying neighboring Santa Barbara County’s raptor program and created a Raptor Study Advisory Committee consisting of experts on raptors from the California Department of Fish and Wildlife; Environmental Department at California State University, Channel Islands; Santa Barbara Natural History Museum; and the Ojai Raptor Center.
For Novak, the raptors didn’t have to be a perfect solution; they just had to be better than the rodenticide bait stations.
In April 2016, two sites were selected at the Revolon Slough in Oxnard for a pilot study. The District constructed 14 perches, made of a pole atop which sat a 2×4, and installed a nesting platform for hawks and an owl box in one area of the slough while in the other, anticoagulant bait stations were used as a control.
The conclusion: Over a seven-month period, the area with the bait stations saw 430 total burrows while the raptor test site saw 145. Similar numbers came from a different area of the slough over a four-month period: 206 total burrows in the bait station zone, 110 in the raptor test site.
“From that point, we decided to expand the program and have been removing over 300 bait stations from our levees and dams and replacing them with perches and owl boxes,” said Novak.
Kimberly Stroud, executive director of the Ojai Raptor Center, says that she gave Novak tips on how to better construct perches and owl boxes for the program and consulted on their placement.
Stroud says that in Ventura County, the primary raptors include red-tailed hawks, great horned owls and barn owls, adding that she rarely handles raptors exposed to rodenticide for one somber reason.
“Unfortunately, we don’t get a lot because it kills them,” said Stroud. “The ones we do get are bleeding out.”
Rodenticides are anticoagulants, and when consumed by raptors, thin the blood to the point that it begins leaking from every orifice, including the mouth, ears and nose.
“We have to give them a coagulant to stop the bleeding and if we don’t get them in time, it’s impossible,” said Stroud, who says that for mammals the effects can be worse than a quick death. “We’ve seen horrible conditions in Ojai in coyotes because of this. They lose all of their fur, get massive sores, and basically starve to death. It’s a pretty horrible death.”
Well-known mountain lions in the Santa Monica Mountains have come to national attention after having succumbed to rodenticide poisoning in recent years. In 2012, the body of a mountain lion was found on a hiking trail in Thousand Oaks, its death the result of rodenticide poisoning. Perhaps the most famous of Southern California mountain lions, P-22, which lives in Los Angeles’ Griffith Park and has been photographed near the Hollywood sign, has also had a run-in with rodenticide — appearing mangy and sickly in 2017 after believed to have consumed prey that had consumed the bait.
Novak says that the program has covered 10 dams and eight miles of levees, and that they still “have a ways to go.”
“Our goal is to replace all of our bait stations with perches and owl boxes,” said Novak, adding that gopher mesh, an expensive but very effective way of preventing damage to dams and levees, will also be utilized to complement the raptors. “We’re just working through it one site at a time now as we have resources to commit to it.”
Novak will present “Raptor Pilot Study – Rodenticides” on Tuesday, Sept. 11, at 7:30 p.m. at the Poinsettia Pavilion, 3451 Foothill Road, Ventura. For more information, visit www.venturaaudubon.org.