Sustainable Living Center Oregon
Truffle Owls ……
Voles, squirrels, chipmunks and gophers love truffles just as much as humans do. If we want to cultivate Truffles we must control these critters.
Bring on the Owls!!
Using owls to control gophers is an option. Installing owl boxes will encourage owls to make their home where we want them. While owls prey on gophers, their habit is to range far from their nesting boxes, so using them as your main gopher control is somewhat unreliable. When a single gopher is damaging an entire farm or crop quickly, quick fixes like trapping or baiting are necessary.
The Western Red-Backed Voles loves Truffles
The western red-backed vole is found in northern California and western Oregon in the United States. The northern limit is defined by the Columbia River, with the range extending south to around 62 mi north of the San Francisco Bay. The range extends from the summits of the Cascade Range in the east, to the Pacific Ocean. They live mainly in Douglas Fir forest.
They live largely underground in an extensive system of burrows. It feeds primarily on fruiting bodies of hypogeous fungi. These mycorrhizal fungi (triffles) are the symbionts of the Douglas Fir trees around it. Rhizopogon vinicolor is one such which is associated with the Douglas-fir. Fruiting of the truffles takes place in well decayed timber when the nutrients are becoming exhausted.
Because the truffles are underground, their spores are not liberated into the air as in most fungal species. However, the spores are found in the vole’s droppings and are deposited throughout its burrows, thus enabling the truffle to spread and form associations with uninfected trees. It has been found that in a clear-cut forest where all the dead wood and trimmings are removed, the mycorrhiza stops fruiting, the vole population dies out and newly planted trees fail to thrive.
This is an example of a three-way symbiosis. The vole gains food from the truffle and spreads its spores. The truffle gains photosynthetic products from the tree which benefits from the nutrients produced by the truffle.
The western red-backed vole, as a denizen of old-growth forests, it plays an important role as prey to a number of species. For the northern spotted owl, western red-backed voles are one of the top five prey species. The red tree vole, northern flying squirrel, and western red-backed vole constitute more than 75% of the spotted owls diet.
To Control Voles we use Owls
Owls are permanent residents and may nest at any season. Their clutch of five to ten white eggs will produce a varying number of the young, depending on availability of prey. Incubation requires three weeks. The young, which vary in size due to their hatching dates, fly at about seven weeks of age. Barn owls often nest in the same site repeatedly.
Barn owls are considered to be our most beneficial owl, owing to their appetite for animal pests. One once was observed delivering 16 mice, three gophers, a rat and a squirrel to a nest within 25 minutes. Common barn owls are threatened by the loss of prey habitat. The barn owl’s primary prey are voles and to a lesser extent mice. The barn owl is found worldwide, nesting almost totally in buildings in the Old World and in hollow trees and burrows in much of the western United States.
Barn owls have become very popular to attract for various reasons. Owners of truffle orchards, and farms have found that barn owls can significant reduce damage by crop-eating rodents. Property owners can benefit the same way with sometimes no more than one or two nest boxes. Conservationists are finding that erecting owl houses is the best way for bringing back numbers of barn owls in areas where they have declined. And bird lovers simply love having them around to enjoy the opportunity of watching these white-faced, golden winged raptors sail out over a field at dusk on the hunt.
The popularity of attracting barn owls has resulted in a wide range of barn owls box designs, both do-it-yourself and those that are marketed commercially. Often, these designs do not take into account the biology and daily needs of these large owls. With so many versions of nest box to choose from, some excellent, some not so good, this article is intended to help barn owl enthusiasts make wise decisions about which elements are ideal for successfully attracting and housing these beautiful raptors.
The Five Most Important Design Elements for a Barn Owl Box
This barn owl box is shallow but long
Location of Entrance Hole: A number of designs call for an entrance hole that is almost level with the floor. This is a poor choice because the ever curious and rambunctious young tend to crowd toward the entrance hole as they get older. This design allows for them to fall out way too early. Always pick a design with the entrance hole at least six inches off the floor.
Wooden boxes should be painted white to keep them cool and repainted every year or two
Material: Most commercially made boxes and available plans use half-inch plywood.
Plywood boxes tend to deteriorate over time
The problem with such plywood is that, after the expense and labor of construction and installation, half inch plywood deteriorates rapidly in sun and rain. The alternate choice, ¾ to 1” plywood will last somewhat longer. The problem with thicker ply is that it creates a box that is very heavy and difficult to install. Our solution is to use a plastic 15-gallon barrel with a removal opening on the back.
If the barrel is to be placed in an exposed situation. Approximately nine drain holes, 1/4 to 1/2 inch in diameter, should be spaced throughout the bottom. Cover the bottom with 1 or 2 inches of wood shavings, as barn owls do not collect nest material.
How to Attract Owls
There are more than 200 species of owls in the world, but only a few are comfortable enough to become backyard species. The most common backyard owls include:
The Great Horned Owl is the most commonly encountered owl in Oregon. It is a large, stocky, powerful owl with large yellow eyes and distinctive feather tufts or “ears” above the eyes. Plumage color varies from dark brown in western Oregon to pale grayish brown in southeastern Oregon. The throat is white.
It is a fairly common permanent resident throughout the state, but generally absent in areas above the timberline.
Depending on the local habitat, regional owl ranges and how attractive the yard is for these birds of prey, other owls may also become backyard visitors.
Barrel Owl Box should be installed high to lessen human disturbance and the dangers of predation from snakes, raccoons and cats. If placed in a barn, the front should face into the barn. The back can be nailed flat to the barn. Usually, a brace or stud can be located on which to secure the box firmly along one side. Metal straps attached on the back can be bent to hang the box in a barn or inside a silo. In some regions, barn owls use boxes that are simply wired in place high in a large tree.
The most productive site for a barn owl box is where individuals have been seen. Due to the species’ rarity, the possibility of attracting them in other areas is remote but worth a try. The best localities are rural. Areas where there are open grasslands and crop fields and where grain spillage results in high mouse populations are especially suitable for nesting barn owls.
Place nest cones in trees in the fall so they can be located by owls by the following January.
Oregon Coast Truffles Company