Agriculture in Minidoka County

Agriculture and farm management

UI Extension, Minidoka County provides timely, research-based information that helps growers control pests, market products and find new varieties. Contact us at minidoka@uidaho.edu or 208-852-1097 for information on current classes and programs.

Barn owl research

You can help with research into the use of barn owls for managing vole populations.  

• Sign up to purchase a box or build your own.
• Once you have a box installed, please contact us. We will send you an agreement form.
• Return the completed form to allow us to come and collect data about the birds nesting on your property. With this data, we can help you and others learn more about barn owl populations and how they may affect agricultural production.

Making and buying nesting boxes

We are in the process of building barn owl boxes with our partners in order to sell them. We are currently working with youth groups including students and at-risk youth to build boxes and teach them about wildlife, carpentry and sustainable agriculture. The cost is $120 with priority to those in Minidoka, Cassia, Power and Oneida counties.

If you are interested in purchasing a box, please contact Jason Thomas at jasont@uidaho.edu or 208-436-7184 to be added to the waiting list. Some vendors also sell other boxes online.

We have been using a design developed by a California shop teacher and bird bander. We are making a few changes for the boxes we are building:

• Extending the roof piece by 1/4 inch on the front, left and right sides to give a better weather-proof seal
• Removing the hinging mechanism at the top since bird banding is not an integral part of our program
• Making the clean-out door bigger for easier cleaning

Plans for Simmons-style boxes

Installing a barn owl box

We recommend that you install the boxes about eight feet off the ground. Studies show that barn owls will nest at this height. Even though owls prefer even higher boxes, cleaning the boxes becomes harder.

We recommend that if the box is outside, then the front (the side with the opening) should face north. According to a thorough study conducted in California, north facing boxes had the highest nesting rates. A study in Israel found that north or east facing boxes had the best nesting rates. Nesting boxes in Caldwell had high nesting rates with northeast facing boxes, but that study had a small sample size.

Boxes should be at least 1,000 feet apart from each other, since barn owls normally defend that much territory. The number of owls an area can support depends greatly on how many voles are available to eat. If you want to start putting out boxes, we suggest that you start with a few boxes. If you have good nesting rates over time, then try putting out some more.  

Research on how many boxes should be placed per acre is still being conducted. Some operations in Malaysia have had successful nesting rates with 1 box per 100 acres. One study performed in California had a high nesting rate with 24 boxes per 100 acres, but this high nesting only occurred during a year when rodent populations were high. The California study suggests that putting out a lot of boxes is not a bad thing, especially if some years have high rodent populations. We will investigate this question in Idaho as our project grows, and we hope to release more information in the future.

Maintaining a barn owl box

Each year that the box has been occupied, it should be cleaned out. If you want to, you can paint the box or stain it so that the wood lasts longer. Adding shavings or straw for bedding may also help with nesting.

An occupied barn owl box needs to be cleaned out yearly, preferably in the fall. The box will be full of bird waste including owl pellets, animal remains and bird poop. This waste often becomes stuck together in a large mass.

We strongly encourage you wear gloves and proper respiratory protection, since contact with bird-transmitted diseases is possible. Use a hammer or tool to break the waste apart, if needed. Put the waste in a large garbage bag and throw it away. Some barn owl researchers suggest putting nesting material (e.g. straw, wood shavings) in the box after cleaning to encourage nesting next year.

Biology of barn owls

Almost all of their diet is voles, but they will feed on other animals such as other rodents, birds or small mammals. Barn owls are a small species of owl that weigh about one pound. The potential for them to attack a fully grown cat or dog is low because the owls are so small. They could feed on a small kitten or puppy if the opportunity presented itself, but they prefer feeding on small rodents instead. Also, the owls are mostly active at night when your pets are inside or sleeping.

Crop production information

Idaho supports one of the nation’s most diverse agricultural economies. Famous potatoes and high-quality wheat are Idaho hallmarks, in addition to dozens of other crops produced by Idaho growers. Visit the UI Extension publications catalog for more information.