The Barn Owl in Texas

Texas Barn Owls

iStock_000020901530MediumBarn owl populations in Texas are excellent and the state is perfect for attracting barn owl families to private properties and establishing nest box programs in agriculture. Barn owls in Texas have been known to nest in trees, cliffs, caves, riverbanks, church steeples, chimneys, barn lofts, hay stacks, deer blinds, and nest boxes.

Barn owls are year-round residents in the state, breeding most commonly February through June, however they have been known to nest in every month of the year. During the winter, they often roost in junipers where they are protected from wind and cold.

They consume voles, pocket gophers, marsh rice rats, cotton rats, Norwegian rats, and mice in such large numbers that they are excellent for significantly reducing numbers of these destructive rodents when attracted to nest boxes.

Distribution of Barn Owls in Texas

Dark blue = excellent populations; Light blue = good to fair; Gray = rare to absent

Dark blue = excellent populations; Light blue = good to fair; Gray = rare to absent

Barn owls are common throughout most of the state except for the forested eastern counties and the high, dry mountains of the Trans Pecos region in the far west. Almost everywhere else this large white-faced, golden-winged owl abounds due to the wide range of agriculture and the prevalence of wild grasslands. As the range map shows, high populations exist in the marsh region along the coast, the sugar cane region of Hidalgo, Cameron, and Willacy Counties in the southern tip of the state, and three major vineyard areas in the panhandle, the north-central edge, and the center of the Edwards plateau.

Texas Agriculture and Barn Owls

Wheat grown across the upper third of the state, sugar cane in the southernmost three counties, rice along the gulf coast, and dairy and cattle farms in the eastern half and panhandle all foster populations of barn owls. Although cotton is not good for barn owl numbers, they are still seen in cotton country.

Texas Wine Country and Barn Owls

Texas has a long history of viticulture, going back to when Spanish missionaries grew BARN_OWL_VINEYARD_842grapes for sacramental wine in the 16th century. Today, Texas is a major grape-growing state, second only to California.

The eight Texas Wine Growing Regions produce a wide array of world class wines. These include the Bell Mountain and Fredericksburg Regions in Gillespie County, the Escondido Region in Pecos County, the Mesilla Valley Region near El Paso, the Texoma Region in the northeast, the Texas Davis Mountains Region in Jeff Davis County, the Texas Hill Country Region located on the Edwards Plateau, and the Texas High Plains Region in the panhandle. All of these regions have unique climates that produce excellent wines.

Using Barn Owls for Natural Rodent Control in Texas

Adult barn owl emerging from nest boxAs in California, Texas vineyards attract large numbers of voles and pocket gophers and these areas have great potential for establishing nest box programs designed for natural rodent control. Quick and high occupancy should be expected in such regions, resulting in less need for trapping and poisoning, both of which are more expensive than using owls. It will not be long before Texas vintners begin to use barn owls to the same degree that California vintners do today. Texas is a perfect state to institute such programs.

But vineyards are not the only places in Texas that harbor dense populations of barn owls. Sugar cane, grown in the three southernmost counties is rife with cotton rats, and barn owls there are always on the lookout for suitable places to nest. The same is true with rice, grown in the moist eastern counties. Large quantities of rice are consumed by marsh rice rats, a favorite prey of barn owls. In areas like these, barn owls cannot find enough nesting sites fast enough and both of these agricultures would benefit immensely from sophisticated barn owl nest box programs. The dairy and cattle farms common throughout the state are also great places for nest boxes, as are the wheat fields of the panhandle.

The Barn Owl Box Company

If you are interested in creating a nest box program in Texas, contact us at the Barn Owl Box Company for any information you might need. We can offer substantial discounts for quantity orders. Look to our Products page for more info on the various nest boxes we manufacture.

Nature’s Remedy: Barn Owl Box Company Distributor in San Luis Obispo, Monterey, and Santa Barbara Counties

Offers Installation and Maintenance of Barn Owl Boxes

Glenn Prichard, owner of Nature’s Remedy, is a distributor of Barn Owl Box Company nest boxes in San Luis Obispo, Santa Barbara, and Monterey Counties in California. His company is dedicated to educating farmers about the benefits of using barn owls for environmentally safe rodent control through the use of nest box programs. In addition to offering our high quality owl boxes for sale, Glenn also provides installation and annual maintenance services for his nest boxes, giving farmers and property owners the peace of mind in knowing that an experienced professional will install the boxes for optimum results and maintain them properly.

Glenn, who has been installing and maintaining nest boxes for several years, observes that California landowners are generally very concerned for the environment and wildlife natural habitats. He adds, “Fortunately people in this area show good stewardship over their land. My goal is to increase the number of barn owls on the Central Coast.  By luring barn owls to nest boxes on their land, property owners are able to keep gophers, rats, field mice, voles and more from destroying precious crops.”

Barn Owl Box Installation Recommendations

For optimum results, Glenn recommends installing boxes every 10 to 15 acres; he supplements his nest box programs by installing tall perches in the middle of rodent colonies to enable other raptors such as red tailed hawks to hunt the vineyards and orchards.

Poor man's billboardOnce a distributor of wooden boxes, Prichard switched over to the Barn Owl Box Company plastic design due to its lightweight, durability, and ease of installation and maintenance.

Along with installing the boxes and perches, Prichard educates property owners about the dangers of using poisons and rodenticides that can kill domestic animals and other wildlife while attempting to eradicate the destructive pests.

Interest in Barn Owl Boxes Increasing in Central Coast Counties

Prichard describes his work as “fulfilling and exciting” as he travels throughout Central Truck and Oso Libre installCalifornia; working with down-to-earth practical people that also care about the environment and wildlife conservation. He adds, “I’ve had a love for animals all my life. I rescue for Pacific Wildlife Care and I see the effect of poison and encroaching development on red-tailed hawks, great horned owls and other animals. The success of my work through Nature’s Remedy has led to inquiries by cities to establish barn owl nesting box programs in their communities.”

Anyone living in San Luis Obispo, Monterey, or Santa Barbara Counties interested in having nest boxes installed can contact Glenn and Nature’s Remedy:

Visit , call Glenn Prichard at 805-712-8609, or email

Nature’s Remedy is a locally owned and operated business that services San Luis Obispo, Santa Barbara and Monterey counties. Professional affiliations include the Independent Grape Growers of the Paso Robles Area, Central Coast Vineyard Team, Central Coast Olive Growers, Paso Robles Wine Country Alliance, Paso Robles Chamber of Commerce and the Templeton Chamber of Commerce.

The Phenomenal Hearing of the Barn Owl

Owls, being nocturnal hunters, have excellent hearing in general, but barn owl hearing exceeds even that of most owls.

barn-owlOf the 216 species of owls in the world, 200 belong to the Strigidae family. The 16 barn owl species belong to a separate family, Tytonidae. This means that the two groups have different lineages and, therefore, possess different traits. Despite the excellent hearing present in the owls of the Strigidae, barn owls have been shown to possess even more refined hearing than most other owls.

Barn Owl Hunting Behavior

Barn_Owl_Flying_8349Anyone who has ever watched a barn owl hunting in twilight – a pale apparition hovering and quartering across an open field – also will notice how the barn owl keeps its head down, its face pointing studiously toward the ground. That face bears some examination. No other owls possess the pronounced concave facial disk that barn owls possess. This facial disk, created by the feathers to form a hollow disk around the entire face, operates very much like a satellite dish—capturing and locating sound. To either side of the disk sit the two ear openings and these, like other owls, are positioned slightly asymmetrically, another adaptation to allow for greater accuracy in pinpointing the exact location of a sound.

Barn Owl Facial Disk

Three barn owls about 4 weeks old

Young barn owls developing their facial disks

The effect of the facial disk is similar to what happens when you cup your hands toward a sound in order to hear it better. The cupped hands collect sound more efficiently than open air. By turning its face toward the ground, the barn owl collects sounds far more efficiently than your cupped hands. Then the asymmetrical ears send the sounds to the brain with two slightly different signals that allow the barn owls to pinpoint the exact location.

So acute is barn owl hearing that, in a research experiment, barn owls housed in total darkness were able to capture live rodents on a bed of dry leaves with stunning accuracy. Of course, this ability to hunt “blind” is also utilized when barn owls plunge their legs into snow or high grass to capture prey. And since barn owls tend to capture a higher percentage of pregnant female rodents than exist in the population, it is theorized that they may be able to differentiate rodents according to age and sex. This would be accomplished by discerning the difference in sound made by larger, heavier bodies moving through vegetation, or even the difference in the sounds made by different sexes and ages while chewing on grass or seeds.

Pocket gopher foraging at feeder hole

Pocket gopher foraging

In my research project in California where we are measuring the effect of a barn owl population on the rodent population, I frequently see pocket gophers foraging. These rather large rodents are some of the most cautious animals in the world. They use “feeder holes” to forage above ground. In their effort to reach plants to eat, they stretch their bodies out sometimes almost all the way, but never allowing the tip of their tail to leave the feeder hole. This allows them to know exactly where to retreat to from danger, and this they do frequently, whether danger is present or not. The idea of capturing one of these fast moving, cautious creatures by hand seems out of the question, no matter how much stealth could be applied. Yet, I have recorded a male barn owl capturing two pocket gophers in under five minutes on a dark, moonless night and delivering them to his female and chicks.

Pacific Gas and Electric Company (PG&E) Teams with the Vineyard Team to Provide Owl Nest Boxes to Vintners


Barn owls eat large numbers of rodent pests

Vintners in the Paso Robles, San Luis Obispo, and Monterey wine making regions have been using barn owls for rodent control for decades. Take a drive anywhere around wine country and you will see numerous boxes installed on poles and posts for attracting these large, voracious rodent predators. Over time, some of these boxes were inadvertently installed in the vicinity of power lines since so many vineyards border roads and rights of way.

This has caused problems for both barn owls and the utility company. When located too near the lines, chances are greater that barn owl mortalities can occur from the high voltage. Owls have even been known to attempt to nest inside transformers. In both cases, expensive and time consuming power outages can result.

In a joint effort that benefits the growers, the owls, and the utility company, PG&E and the Vineyard Team of the central coast of California have been collaborating for the past three years in efforts to relocate nest boxes a safer distance from these hazards. The Owl Safety Program provides nest boxes free of charge to members of the Vineyard Team and provides growers with practical information from owl researchers on where to locate nest boxes, and proven methods for attracting and maintaining barn owls.

“We’re trying to educate customers and get the word out that utility poles are not the appropriate place to install nest boxes.” said Mike Best, PG&E’s Avian Protection Plan Program Manager. This year, a $10,000 charitable grant from Pacific Gas and Electric Company will help grape growers in the Central Coast maintain sustainable pest control and also keep birds safe around power lines.

Adult barn owl emerging from nest box

Molded plastic barn owl box

The Barn Owl Box Company will be supplying its specially designed, molded plastic barn owl boxes to the project this year. Barn owls, at 12 to 14 inches high, need large cavities to nest in. Since these can be scarce, owls bent on raising young have been known to nest in feed hoppers, deer blinds, old barrels left on the ground, crevices in lava beds, holes in riverbanks, dead palm fronds, cisterns, and even a hundred feet deep in abandoned mines. Some of these locations may not result in successful nesting, so the installation of nest boxes is an excellent conservation move and provides an efficient rodent control method for vintners.

Mark Browning, founder of the Barn Owl Box Company and long-time barn owl researcher, will address the Vineyard Team members at Scheid Vineyards in Greenfield, California on February 18th. His presentation will detail his research on how barn owls can significantly reduce rodent populations on vineyards.

The Owl Safety Program is now in its third year. Anne Jackson, Senior Environmental Program Manager with PG&E’s Environmental Policy Department, says that the program has been so successful that they are looking to expand its reach to benefit more customers.

“It’s a great opportunity to educate growers about the use and proper placement of owl boxes as a sustainable farming practice. The program is receiving a lot of positive feedback and growers from all over are contacting us with interest in expanding it to their community,” said Anne Jackson.

“This program is a great example of how our community partnerships and investments can help address the needs of our customers while also supporting our business objectives.” added Diane Ross-Leech, Environmental Policy Director for PG&E. For more information, visit PG&E’s habitat conservation and land stewardship programs page.


Vineyards Harbor Diverse Widllife

“This kind of enlightened collaboration shows what can be done when business and non-profit organizations work together toward common goals,” said Browning. “I am delighted that establishing strong and healthy populations of barn owls is being given such emphasis. Using barn owls instead of poisons is a win-win situation for the growers, the owls, and all of the indigenous wildlife that lives on the vineyards.”

The Vineyard Team is a non-profit organization dedicated to promoting sustainable Vineyard Team logo _2013-01viticulture practices on the Central Coast of California since 1994. Visit the Vineyard Team Website.

Choosing a Barn Owl Box that Works


Barn owls can easily be attracted to nest boxes

Barn owls have become very popular to attract for various reasons. Owners of vineyards, 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

This barn owl box is shallow but long

1. Appropriate Size:  Too many barn owl box designs create a nest box that might be only 18” deep. While this size can attract a breeding pair, keep in mind that barn owls produce an extraordinary number of young—seven is quite common. And keep in mind that the entire brood of owls must reach adult size inside that nest box before fledging, each of them 12 to 14 inches high, and flapping their wings in preparation for flight. In such small boxes, flight feathers are damaged, smaller birds are not found to receive food, and young birds are pushed accidentally from their nest boxes. In short, fewer birds survive from such owl houses. Rule of thumb: select designs that are at least 24” deep, 18” high, and 18” wide.

2. Size of Entrance Hole:  Many designs err on the size of the entrance hole, usually making them too large. All cavity nesting birds, including barn owls, prefer an entrance hole that is just large enough for them to squeeze through, but too small for larger animals that might prey on the eggs or chicks. Numerous designs dictate a six or seven inch hole. This is far too large and may cause barn owls to shun such a nest box. Other designs call for a hole as small as 4 ½” inches. Although some barn owls can fit through, barn owls vary in size, with females being larger than males and American barn owls larger than those in Europe. Choose a design with a 5” to 5 ½” entrance hole.

3. 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

Wooden boxes should be painted white to keep them cool and repainted every year or two

4. Color:  Many wooden boxes are left natural to blend into the environment. While this may satisfy certain aesthetics, the problem is that most wooden boxes are heat traps especially in western and southern states. As the sun beats down on dark wood, the interior can become excessively hot. Biologists have found young owls, too young to leave the nest, on the ground where they took refuge from the stifling heat inside wooden boxes. If you do buy or make a wooden box, be sure to paint the entire outside with bright white paint to reduce heat absorption and plan to repaint every year or two.

5. Material:  Most commercially made boxes and available plans use half-inch plywood.

Plywood boxes tend to deteriorate over time

Plywood boxes tend to deteriorate over time

The problem with such thin ply 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. So, when it comes to plywood owl houses, the choice is between longer life and ease of installation. If you are buying a wooden box, ask the builder the thickness of the wood.

Using these basic guidelines, you should be able to select either a do-it-yourself plan or a ready-made owl house that will provide an ideal environment for a barn owl family. For more information on our own manufactured designs, go to our Product Page. Our two molded plastic models, are pictured below. We offer one design for putting on poles, The Pole Model, and another for inserting into barns and outbuildings, The Barn Model. Good luck with your barn owls!

Post-ModelBarn Owl flying from barn model




California Barn Owls

While great stretches of the United States, from New York to Iowa, have seen a decline in barn owls since the 1950’s, the state of California maintains surprisingly robust populations of this beautiful white-faced, golden winged owl. In fact, in a state with a wide variety of common raptors, the barn owl may very well be its most common avian predator. iStock_000020901530MediumThough not seen as readily as many hawks due to its nocturnal habits, barn owls nest in large numbers throughout much of the state. They inhabit old barns, outbuildings, silos, bridge girders, holes in cliffs, and even aviation hangars. The author has even seen breeding pairs inhabiting holes in large trees along a busy street in heavily populated downtown Davis. Waitresses in the restaurants there often observe the owls swooping down on rodents that had been attracted to food that humans had dropped earlier in the courtyards and shopping areas that day. This may be the first description of barn owls going to restaurants for their meals! One of the reasons for the abundance of these owls in California is the abundance of wide open spaces in much of the state, much of it natural grasslands. On top of that, much of these grasslands have been converted to irrigated agricultural fields where rodent populations increase significantly, only making the land more agreeable to this voracious rodent predator.

Barn Owls in Vineyards and Orchards

BARN_OWL_VINEYARD_842Recognizing the value of having winged rodent killers on their property, California farmers have led the nation in utilizing barn owls as integral parts to their integrated pest management programs. Growers of grapes, cherries, plums, almonds, and walnuts have been using barn owls for decades now. Literally thousands of nest boxes have been erected in the state and this effort has helped allow barn owls to flourish in the landscape. Their nest box of choice is one that mounts to a metal pole or wooden post. Here is a link for more information on our Barn Owl Box Pole Model.

California Barn Owl Box Programs

The Pole Model Barn Owl Box made by the Barn Owl Box Company of molded plastic

The Pole Model Barn Owl Box made by the Barn Owl Box Company of molded plastic

In California, it is not unusual to put a barn owl box up one day, and find barn owls in it the next. Farmers with large nest box programs typically have eighty to one-hundred percent occupation rates. In a research project designed to determine best methods of creating a nest box program, the author attracted 18 breeding pairs to a single 100 acre vineyard in 2012. These 36 adults fledged 66 healthy young for a total of 102 birds hunting the vineyard by mid-summer. This population on one hundred acres was more barn owls than biologists in Pennsylvania believe exist in the entire state! Such dense populations can take a significant number of rodents and effectively reduce damage to crops and annoyance to farm operations. And the use of barn owls for natural rodent control is growing. Increasingly, farmers are sophisticating their nest box programs by erected larger numbers of nest boxes to ensure that the barn owls can harvest significant numbers of rodents. But farmers are not the only ones interested in having these beautiful owls around: large numbers of property owners are also erecting owl houses around their homes. (Barn owls are aptly named since they do not mind living around human activity.)

Common Rodent Pests in California

Pocket gopher mounds

Pocket gopher mounds

California happens to have dense populations of rodents as well as any California resident will tell you. Mounds, trails, and runs dot the landscape. Different species of rodents dominate different areas, mainly due to moisture and soil types. Two of these species are the most damaging to crops, the pocket gopher and the vole. Whereas vineyards in the Lodi region harbor a majority of pocket gophers, vineyards in Napa and Sonoma are often dominated by voles. Sometimes these two species thrive on the same land.  Both the pocket gopher and vole cause damage to vines, fruit and nut trees, irrigation systems, cover crops, and the integrity of the soil. So the use of barn owls has become a rodent control method of choice for many farmers and property owners.

Barn Owl Distribution in California

The barn owl is common throughout the state except for forested areas and very high elevations which they avoid. The deserts of the southern parts of the state do harbor barn owls, but not in the great numbers that exist in the fertile agricultural regions, wetlands, and grasslands. Even people in the suburbs of large cities like San Francisco, Los Angeles, and San Diego have successfully attracted these large owls.

More Information about Installing Barn Owl Boxes

If you are interested in putting up a barn owl box, make sure you visit our blog post on Best Methods of Installation. For any further questions, email us at

How to Install Barn Owl Boxes for Success in Controlling Rodents

The History of Using Barn Owls for Natural Rodent Control

Three barn owls about 4 weeks oldBarn owls have now been used for decades by U.S. vintners, orchardists, and property owners as a means of natural rodent control. California has led this effort, with thousands of nest boxes erected on farm land. If you travel anywhere in the state, you will see large barn owl boxes on tall poles situated here and there in the landscape. Other states are beginning to use barn owl nest boxes in increasing numbers. But barn owls were first used in extensive nest box programs in Israel, Malaysia, and South East Asia. These large owls are uniquely suited for rodent control programs due to their voracious appetites, high production of chicks, and attraction to nest boxes. Their willingness to live in close proximity to other barn owls allows for the attraction of dense populations. So the potential for creating barn owl nest box programs that can significantly reduce rodent populations is good whether you own a thousand acres of vines or a small property.

However, as with any rodent control approach, it is important to utilize methods that are effective. Important questions that are most often asked are (1) How many owl houses should be installed for a given acreage? (2) Where should the nest boxes be placed? (3) How high off the ground should the nest boxes be installed? (4) Do barn owls prefer a certain direction for their entrance holes to face? (5) Should substrate be added to the floor of the nest box? (6) Which species of rodents are barn owls effective against? (6) How often should I clean a barn owl box?

The Barn Owl Box Company Research Project

Adult barn owl emerging from nest boxIn order to help answer these questions and provide farmers and property owners with practical information for establishing barn owl populations, the Barn Owl/Rodent Project was begun in early 2011 on a 100 acre vineyard located near Elk Grove, CA. Eventually 25 nest boxes were erected along the perimeter of the vineyard, facing in four directions, NE, SE, NW, and SW. In 2011, eleven nest boxes became occupied by breeding pairs. These 22 adults fledged 44 young that year. In 2012, eighteen boxes housed breeding pairs and these 36 adults fledged 66 young, for a total of 102 owls hunting the vineyard. This was by far the largest population of barn owls ever attracted to such a confined area, illustrating just how colonial barn owls are and just how many of them can be attracted to a small area in a short period of time.

Our research team not only monitored nest box occupation of adults and chicks, but also conducted a monthly census of pocket gopher activity (the most prevalent rodent in the study area). These two ongoing surveys gave us two lines of data that we could compare to determine if barn owl numbers had a correlation to rodent activity. We also collected and analyzed the contents of the regurgitated pellets found at the occupied nest boxes. This showed us which rodents were being taken, and how much each species contributed to the barn owl diet. And in 2013, we installed cameras in two occupied nest boxes to tabulate how many prey items were being brought in over the course of the breeding season. This information has allowed us to determine how many rodents are taken annually by a given number of barn owls in a setting similar to that of our study area.

Frequently Asked Questions about Barn Owl Boxes

barn-owl-1(1)    How many nest boxes should be installed for a given acreage? Of all the questions, this must be the most important to the farmer or property owner. Too often we have seen fifty and one hundred acre plots with one or two nest boxes installed. The problem is the high reproductive rate of rodents. The barn owl population must get ahead and stay ahead of that reproductive rate. Keep in mind that on irrigated land, rodent pests and reproduce at a rate 500% greater than on non-irrigated land. Our study showed that you could establish a pair of barn owls, at least for one season, for every five and a half acres. Our feeling is that this may have been, forgive the pun, overkill. Our best educated projection is that, on irrigated farmland, one box for every ten acres may be an excellent starting point. Another, more conservative approach, would be to establish one box for every twenty acres, then wait and see what the barn owls tell you. If you get nearly 100% occupancy, consider adding boxes. In the end, a barn owl population will act much like any population of predators in the wild: eventually the prey is thinned out, and the predator numbers go down. Then, in subsequent years, as the prey population re-establishes itself, predators (especially ones that fly) return. The difference now is that the farmland is being kept far more in balance than it was prior to the establishment of barn owls.

(2)    Where should the nest boxes be placed? Since barn owls fan out over the surrounding land to hunt the most productive areas, the answer is that nest boxes can be placed in the most convenient locations for the farmer, out of the way of machinery and other operations. Boxes can be placed as little as fifty feet apart since barn owls are not territorial. It would be good practice, where possible, to locate them away from power lines and highly traveled roads.

(3)    How high off the ground should the nest boxes be installed? Information persists on the internet and by word-of-mouth that barn owl nest boxes need be placed at ten or twelve feet or even “as high as possible.” The fact is that barn owls will nest on the ground, in the ground, and have been observed breeding in nest boxes five feet off the ground. Our study showed that eight feet up is an excellent height. Higher installations are not only unnecessary, but they add extra expense to a nest box program, and make maintenance of nest boxes more difficult.

(4)    Do barn owls prefer a certain direction for their entrance holes to face? Experience has shown that barn owls will nest in any direction. However, our study has shown a preference for easterly facing directions (NE, SE, or E). This is a thermoregulatory choice: easterly facing directions warm up with the rising sun after cool nights; likewise, they are cooler in the heat of the afternoon. Southwest was the least preferred direction.

(5)    Should substrate be added to the floor of the nest boxes? Word-of-mouth sometimes indicates that substrate is not needed—that the barn owls use their own pellets for substrate. But this is ill advised: barn owls do not produce pellets fast enough to cover the bottom of the nest box, and the eggs roll around on smooth floors and are easily broken. Always add three or four inches of bark mulch to the entire floor. We have seen barn owls shun boxes without substrate. Get the large pieced bark mulch instead of the finely ground material.

(6)    Which species of rodent are barn owls effective against? Barn owls are highly adaptive, eating the most prevalent rodents in their area. In sugar cane they eat the very common cotton rat. In rice, they eat marsh rice rats. In areas of California where the vole is most common, that becomes their most common prey, and likewise for areas inhabited by pocket gophers. In our study, the barn owls consumed approximately 80% pocket gophers, and 20% voles, with occasional rats.

(7) How often should a barn owl box be cleaned, and what time of year? Barn owls neither bring nesting material to the nest box, nor do they clean their own nests. After breeding season, between October and December, is the best time. But check for occupancy first! Barn owls are known to breed in the off season as well. Simply removed the old mulch and replace it with new. This should take only fifteen minutes or so per box.

Join those Using Barn Owls for Conservation and Rodent Control

Attracting barn owls in areas they already live is easy by putting up an owl house. Once established, barn owls remain faithful to their nesting sites. And the sight of a barn owl slowly traversing a field in search of rodents is a riveting experience.