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Barn Owl Research

Research on Barn Owls

How can I help with barn owl research?

  • 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

Are barn owl boxes available to purchase?

Yes, 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.

  • Waiting list only
  • Cost: $120
  • Priority counties: Minidoka, Cassia, Power, Oneida
  • Contact: or 208-436-7184 

If you are interested in purchasing a box, please contact Jason Thomas at or 208-436-7184 to be added to the waiting list. The cost for a box is $120 unless you choose an add-on. Please let us know how many you are interested in buying and what county you live in. Sales will be made higher priority first to areas where data is being collected (Minidoka, Cassia, Power and Oneida counties). We hope our program will expand to other counties as we build more boxes, collect more data and build more partnerships.

Some vendors also sell other boxes online.

Jason Thomas

Extension Educator

A junior barn owl being shown in a classroom
A junior barn owl being shown in a classroom.

How do I build my own box?

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
building an owl box
Building an owl box.

Installing a Barn Owl Box

How high do I install my 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.

Which direction should my box face?

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, Idaho had high nesting rates with northeast facing boxes, but that study had a small sample size.

How far apart should I put multiple boxes on my property?

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

What do I need to do to maintain the 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.

barn owl box set on a side of a barn
Showing an owl box installed on a barn.

How do I clean out the box?

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.

  1. We strongly encourage you wear gloves and proper respiratory protection, since contact with bird-transmitted diseases is possible.
  2. Use a hammer or tool to break the waste apart, if needed.
  3. Put the waste in a large garbage bag and throw it away.
  4. 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

What do barn owls eat?

Almost all of their diet is voles, but they will feed on other animals such as other rodents, birds or small mammals.

Will barn owls harm my pets?

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.

A junior barn owl being shown in a classroom
A junior barn owl being shown in a classroom.


UI Extension, Minidoka County

Mailing Address:
85 East Baseline
Rupert, ID  83350-1608

Phone: 208-436-7184

Fax: 208-436-6889



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