Their compensation will come in the form of grass, mosquitoes and gophers.
Under supervision by a goat herder, several hundred goats and sheep will be on-site around the clock to graze in several city locations including Alum Rock Park and portions of the Evergreen area.
Bat boxes and barn owl boxes have been installed in several city parks and community gardens to help control mosquitoes, gnats, gophers and mice.
"The first measurable benefit (of using the animals) is a reduced level of pesticide or herbicide," says Matt Weber, environmental services specialist for the city. "The second benefits are saving in gas and fuel, and fuel meaning dry vegetation."
The grazing by the goats and sheep consumes a lot of the dead, dry vegetation in fire-prone areas such as Alum Rock and Evergreen, which helps reduce wildfire risk, Weber says.
The amount of vegetation or fuel consumed by each goat or sheep is about five pounds per day. About five tons of dry vegetation was consumed in about a week in Alum Rock Park, Weber says.
"It helps neighbors rest easy because I know they're concerned about fire risk," he says.
This is the second year of a pilot program for utilizing sustainable, less-toxic pest and land management. Last year less than five acres were grazed, this year about 68 acres in eight different sites will be grazed.
Natural pest management methods are growing in popularity in part because of a greater focus on the environment, and now with the increasing cost of gasoline and other goods, there will be long-term economic benefits as well.
The upfront cost of using natural pest management is slightly higher, Weber says, but he adds that over the long term the cost will be offset by the benefits.
Goats and sheep munch their way through grass and other vegetation that would normally be treated with pesticides or herbicides, and reducing the use of those products benefits local streams, the San Francisco Bay and other habitat areas. Additionally, as the grazers remove nonnative vegetation the native vegetation, which is more drought-tolerant and in some cases less flammable, stands a better chance of surviving.
"The benefit is not purely environmental when you consider fire prevention benefits and health benefits," Weber says.
The cost per acre for grazing varies considerably based on type of weeds to be controlled, slope of land, and other characteristics, but averages at about $715 per acre per one-time graze.
"It's safe to say that the cost for grazing is a little more than pest management using herbicides or lawn mowing, but with the reduced fire risk, it really can be priceless," Weber says.
The metal bat boxes on posts, considered long-lasting and maintenance free, ran $145 each in 10 community gardens including Jessie Frey, La Colina, Coyote Creek, Nuestra Tierra, Mayfair, Laguna Seca, Latimer and Calabazas. Educational signs, at about $500, were posted to help explain the use of bats as a biological control and as one of nature's most effective pest controllers with some species able to eat up to 1,200 mosquitoes an hour.
Bats normally roost in caves, trees, twig piles, buildings and bridges, and in Santa Clara county 14 species are indigenous.
To encourage barn owls, which eat gophers and mice, about 32 barn owl boxes at about $57 apiece were installed in the Laguna Seca Community Garden and city parks including Alum Rock, Berryessa, Noble, Penitencia, Santana Wallenberg, Guadalupe Oak Grove, Groesbeck, Meadowfair, Silver Creek Linear, Evergreen, Kelly, Almaden Lake, Basking Ridge, Edenvale, George Page and Lake Cunningham.
Gophers are known to damage underground irrigation lines, and their burrowing in parks creates uneven and unsafe surfaces. Owls will hunt and eat the gophers saving city staff the task of baiting, trapping or fumigating, which is the traditional method of gopher control.
Educational signs explaining the benefits of the owl boxes have also been posted.
It can take a few years for bats and barn owls to find and use the boxes, but patrons of the parks and gardens have already spotted evidence of both bats and barn owls in several locations, Weber says.
The grazing animals can be seen at the various locations, and Weber says the goats and sheep seem to be getting a lot of attention this year. It seems their entertainment value is an unforeseen benefit of the grazing animals.
"Mostly people are just curious. It's not normal to see grazing animals in the city," he says.
And that curiosity is helping Weber's department educate others that land can be managed in a more environmentally responsible and sustainable way rather than applying herbicides or using mechanical methods, he says.
Grazing animals can be seen in Alum Rock Park 12 acres near Boulder Drive, 3 acres near the park parking lot, and six acres off Carothers Road.
Public viewing sites accessible in the Evergreen area are 4.5 acres immediately across Running Springs Road from Early Morning Lane; 8 acres on the east side of Running Springs road north of Hawkcrest Circle; and 3 acres northeast of Running Springs Road southwest of Grand Oak Way.
The Municipal Water Sites are gated, inaccessible, and not good for public viewing, according to a statement.