From the Summer 2021 problem of Living Bird journal. Subscribe now.
Birds are good for greater than controlling crop pests in Southern California’s Ventura County, the place Barn Owls and different raptors shield a completely totally different useful resource—56 flood-control dams and 40 miles of earthen levees—from burrow injury by floor squirrels and gophers.
A single gopher can excavate a ton of soil a 12 months, and floor squirrels can burrow greater than 30 toes. Networks of tunnels undermine levees.
“That’s truly occurred,” says David Torfeh, the raptor program coordinator for Ventura County Watershed Protection Operations and Maintenance. “A sinkhole opened up when a truck was driving over it.”
The larger hazard is a surge of runoff that can blow out a dam or levee, flooding property and even threatening lives. Ventura County had been utilizing rodenticides to manage squirrels and gophers for years, however managers had been involved that non-target animals—similar to coyotes, bobcats, and mountain lions—may eat the bait or poisoned rodents. Several years in the past they investigated a program in neighboring Santa Barbara County utilizing raptor perches to draw hawks, owls, and falcons that management pests.
Soon after, Ventura County launched its personal program, putting in 14 T-shaped perches, every 20 toes excessive, alongside a mile of earthworks. As Torfeh says, they aimed to draw “any raptor that hunts for mammals.”
The perches labored, as Torfeh and his colleagues started seeing Cooper’s Hawks, White-tailed Kites, Red-tailed Hawks, Great Horned Owls, Northern Harriers—a couple of dozen species in all. They additionally put in nest bins and a platform. Some 40% of the bins attracted nesting Barn Owls.
In follow-up research to check the raptor-patrolled space to a close-by space baited with rodenticides, Torfeh and colleagues discovered that raptors had been as much as 67% more practical than rodenticides in controlling rodent burrows.
“The outcomes had been fairly wonderful,” Torfeh says.
Now the county has put in greater than 200 raptor perches and about 20 owl bins on 30 miles of levees.
“Raptor perches save us about $7,500 a 12 months in comparison with utilizing anticoagulant [rodenticides] and a contractor who’s expert at pesticides to watch them,” Torfeh says. “We’re getting the phrase out to agriculture via the useful resource conservation districts of California about this system, as a result of the extra they use it the higher it’s for the setting.”