Introduction

The Barn Owl is a creature that conjuresimages of mystery and intrigue in many peo-ple and for good reason. This animal is oneof the most secretive and highly effectivenighttime predators in the world. The effec-tiveness of the Barn Owl in controllingrodents, including mice and voles, is unri-valed in the animal kingdom.

The value of one Barn Owl to a farmermay be worth its weight in gold. It hasbeen estimated that during a Barn Owl’slifetime (assumed at 10 years) it would

eat approximately 11,000 mice.These 11,000 mice would have each

eaten approximately 10 percent oftheir weight in food per day.

These11,000micemight

have con-sumed or

fouled an esti-mated 13 tons of

growing crops, seeds, andgrain in their lifetime. For thisreason, every Barn Owl living

on a farmer’s property isclearly worth several

Fact Sheet 795

8

The Barn Owl: Friend of Agriculture and Communities

by

M. Allan DalyExtension EducatorBaltimore County

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, University of Maryland, CollegePark, and local governments. Thomas A. Fretz, Director of Maryland Cooperative Extension, University of Maryland.

The University of Maryland is equal opportunity. The University’s policies, programs, and activities are in conformance with pertinent Federal and State laws and regulations onnondiscrimination regarding race, color, religion, age, national origin, sex, and disability. Inquiries regarding compliance with Title VI of the Civil Rights Act of 1964, as amended;Title IX of the Educational Amendments; Section 504 of the Rehabilitation Act of 1973; and the Americans With Disabilities Act of 1990; or related legal requirements should bedirected to the Director of Personnel/Human Relations, Office of the Dean, College of Agriculture and Natural Resources, Symons Hall, College Park, MD 20742.

The Barn Owl: Friend of Agriculture and Communities

P2002

4x4 INCH POST

HOOK AND EYE

CLEAN OUT FLAP

PREDATORGUARD

DRAINAGE HOLES

SIDE VIEW BOTTOM VIEW

L-BRACKETS

ROOF

1/4 IN. CARRIAGE BOLTS

SUN SHIELD

2X2 INCH SPACERS

FIGURE 3. Side and bottom views

hundred dollars in reduced crop damage andother benefits. This fact sheet will describemany aspects of the Barn Owl including iden-tification, distribution, habitat preferences,food habits, and how to try to attract BarnOwls to your property.

Unfortunately, Barn Owls have not alwaysbeen held with such high regard. Until thelate 1970’s, Barn Owls were often shot bylandowners because they were consideredvermin. Because Barn Owls hunt by night,their ability to control rodents was notknown by the average landowner. As educa-tion regarding the Barn Owl increased, nega-tive actions against Barn Owls decreased.

Barn Owls and all other raptors or birds ofprey (hawks, owls, eagles, falcons, and vul-tures) are protected under the Migratory BirdTreaty Act. The law states that it is illegal tohandle, harm, or harass these birds or theirnests in any way.

IdentificationIt has been referred to as the monkey-faced

owl, ghost owl, and spirit owl. Regardless ofthe name you choose the Barn Owl is defi-nitely unique. The Barn Owl is the onlymember of its family (Tytonidae) in NorthAmerica. It differs from other owls, such asthe great horned owl and barred owl, in threeprimary ways. The Barn Owl has a heart-shape facial disk unlike other owls’ facialdisks that are normally round. It also has acomb-like claw on its middle toe that is notpresent on other owl species. Finally, theBarn Owl has a relatively short and squaretail, where other owls have longer, morerounded tails.

The most common identifying marks ofthe Barn Owl include the bright white underbody and the heart-shaped facial disk. If seenin the field, these two features normally giveit away. Also, if you happen to hear an owl"hooting" at night, it most likely is not a BarnOwl. The Barn Owl does not "hoot" likemany other owls. The owl’s call has beendescribed as a shrill, rasping hiss or snoresuch as kschh or shiiish.

DistributionThe Barn Owl is one of the most widely

distributed raptor species in the world. It canbe found on every continent exceptAntarctica. The bird is also found widelythroughout the United States except for theAppalachian Mountains, northern NewEngland and the northern plains areas.

In Maryland, Barn Owls can be found inmost every county except for far westernMaryland. Concentrations of nesting BarnOwls have been identified in several countiesin central Maryland and the Eastern Shore.

HabitatThe habitat preferred by the Barn Owl is a

mixture of grasslands, groves, farm fields,and pastures. The birds prefer to roost in oldbuildings, silos, and of course barns. BarnOwls favor low arable land as well as marshesnear the Chesapeake Bay. The birds haveeven been found nesting in hunting blindsalong marshes of the Eastern Shore.

Barn Owls are traditionally cavity nesterswhich means they prefer to raise their youngin a large hole in a tree or in an appropriatespot in a barn or silo. Removal of older treeshas created a limited number of cavities fornesting Barn Owls. For this reason, we canencourage Barn Owls to use nest boxes, ifproperly constructed and placed around suit-able habitat, that mimic their traditionalnest sites.

Food HabitsBarn Owls eat a wide variety of prey.

However, while studies show their diet maybe diverse, they tend to concentrate themajority of their hunting efforts on just a fewspecies. Small mammals, including mice,voles, and shrews make up the largest portionof their diet. Other food items taken less fre-quently include bats, birds, lizards, andinsects. It is important to note that BarnOwls do not eat chickens.

Barn Owls normally start to hunt arounddusk or even before dusk at times. If greathorned owls (a major predator of Barn Owls)are known to be in the area, Barn Owls may

2 7

TOP SUNBAFFLE

BACK SUNBAFFLE

ROOF

R. SIDE

L. SIDE

FRONT

BACKFLOOR

15.7515.75

15.75

16.75

6

23.7523.75

23.75 17

16

16

17

11 6

5

6

2

CLEANOUTFLAP

PREDATOR GUARD

DISCARD

DISCARD

4x4 INCH POST

FRONT VIEW

BACKSUN BAFFLE

PREDATORGUARD

FRONTPANEL

TOP ASSEMBLY

L-BRACKETSROOF

TOP SUNBAFFLE

2X2 INCHSPACERS

10

FIGURE 1. Plywood sheet cut template

FIGURE 2. Front view

Appendix

Parts List1. One sheet of 1⁄2-inch CDX plywood (5

ply).2. One 16 foot 4x4 post (redwood or pres-

sure treated) to extend 12 feet above ground. 3. Four 1-inch L-brackets with eight 3⁄4-inch

No.10 flat-head sheet metal screws.4. Two 41⁄2 -inch by 3⁄8-inch carriage bolts

with nuts and washers for mounting the boxto the post.

5. Two 2x2-inch tight pin hinges withscrews.

6. Two 13-inch 2x2's for spacers.7. One 11⁄2-inch hook and eye for clean out

door.8. Four 31⁄2-inch by 1⁄4-inch carriage bolts

with nuts and washers for top assembly.9. 11⁄4-inch galvanized box nails.10. Paint or stain (light natural wood color

or clear stain).

Note: This nest box design may beinstalled in a tree, on a post, or in a barn orsilo. The diagram specifically shows how toinstall the nest box on a post.

General instructions: All joints must beglued before nailing. Nails should be placed 1⁄4inch from edges, spaced 3 to 4 inches apart. Ifnail does not go in straight, remove with pli-ers before finishing pounding.

Step 1. Cut plywood sheet as shown.Measure, mark and cut entrance hole onfront. Drill four 1⁄2" holes in the bottom fordrainage. Cut 6"-wide clean-out flap from endof one side.

Step 2. Nail back panel to left side, thenturn assembly over and nail front panel toleft side. Insert floor between front and backpanels. Align lower edges and nail throughfront into the floor. Carefully turn assemblyover and nail through back into floor. Insertupper portion of right side between front andback panels. Align upper edges and nailthrough back. Turn over. Again, align upper

edge and nail through front. Nail through leftpanel into floor.

Step 3. Attach hinges to upper edge of flapthen attach to lower portion of right panel.Drill 1⁄8" hole in lower edge of flap and screwin eye. Measure 11⁄2 inches from eye on floor.Mark, drill, and screw in hook. Glue predatorguard to inside of front and to floor. Setassembled box aside for 24 hours to allowglue to dry.

Step 4. Position roof, spacers and sunshield as shown (sun shield is recommendedif the box is placed on a pole in an openarea). Clamp together and drill through allpieces with 1⁄4" bit. Fasten together with 1⁄4"carriage bolts. Position L-brackets on under-side of roof as shown and attach with screwsso that they will fit over the edges of the sideand front panels.

Step 5. Paint or stain all exposed surfaces.

Step 6. Center back of box on one end ofpost with upper edge of box flush with top ofpost. Drill through box and post togetherand attach with 3⁄8" carriage bolts. Position topassembly and attach by screws through L-brackets.

Barn Owl nest box plans reprinted and adapt-ed with permission from Tom Hoffman ofBiodiversity Products.

Additional ResourcesMaryland Department of Natural

Resources, website: www.dnr.state.md.us.

Fact Sheet Reviewers

Joel FloryWildlife Specialist

Utah State Cooperative Extension Service

Glenn TherresBiodiversity Program Manager

Maryland Department of Natural Resources

Robert TjadenRegional Specialist, Natural Resources

Maryland Cooperative Extension

limit their hunting to the darkest hours ofthe night. Barn Owls normally hunt by flyingup and down open grassland or field areaslooking and listening for prey. At times theywill fly against the wind so that they will notfly too quickly, missing potential prey animals.

Why Try to Use Natural PestControl?

When trying to manage rodent popula-tions, it is important to remember that BarnOwls will not remove all rodents from agiven area. That is not how Mother Natureworks. However, Barn Owls are capable ofmaintaining a rodent population at normallyacceptable levels.

There are a few advantages to using BarnOwls for rodent control. First, rodenticides(rodent poisons) that come in the form ofbaits, pellets, or powders will likely costmore money over the long term than erect-ing a Barn Owl box. Certain rodenticideshave the ability to travel up the food chainand harm or kill non-target or even benefi-cial animal species.

The Barn Owl vs. theDomestic Cat for Rodent

Control Research has shown that a Barn Owl

throughout the course of a year will consumeapproximately 3 to 5 times the number ofrodents that a cat consumes. Also, cats areresponsible for killing a large number ofbirds, most of which are not considered pests.A study conducted in Wisconsin suggests thatcats allowed to go outside, whether in anurban or rural setting, are responsible forkilling approximately 39 million birds a year.It is important to note that this figure onlyrepresents the birds killed by cats in the stateof Wisconsin in one year. The national esti-mate for the number of birds killed by catseach year is 465 million.

Barn Owls are part of the natural land-scape, while domestic cats are not nativepredators in North America. Research isshowing that cats are having a profoundly

negative impact on small mammal and birdpopulations around the country. When itcomes to effectively and naturally controllingrodents, the Barn Owl is far superior to thedomestic cat.

Conservation and Status inMaryland

As mentioned earlier, before many educa-tional campaigns regarding the Barn Owlwere conducted across the country, manyBarn Owls were shot and hung out on fenceposts to supposedly deter other owls fromcoming around. If Barn Owls were founddead, but not shot, they often died as a resultof poisoning. Many of the anti-coagulanttypes of rodent poisons available on the mar-ket can be transmitted up the food chain.The owls would, and still do, ingest mice thathave been poisoned and they in turn are poi-soned and become very sick or die.

Today, the Barn Owl population inMaryland is considered to be stable through-out its range, although continued habitatdestruction from development may poseproblems for the population in the future.We may play a vital role in the future of theBarn Owl’s success by providing nesting sitesneeded to ensure a stable population.

Providing Nesting Sites forBarn Owls

Barn Owls will nest in properly constructedand mounted nest boxes. The birds are notconsidered to be finicky and will nest in avariety of places that are dark and normallyelevated at least 12 feet above the ground.

Plans for building a Barn Owl nest box maybe found at the end of the fact sheet.

Barn Owls do not exhibit strong territorialinstincts and will nest relatively close toother Barn Owls if adequate food is present.For this reason, nest boxes may be placed afew hundred yards apart. Research fromCalifornia suggests that between four to sixBarn Owl boxes can be placed in a 50-acrearea. This does not suggest that 50 acres ofland is needed to attract Barn Owls. If theproper habitat is available with a proper nest

6 3

site, along with available food, Barn Owlsmay be attracted to the area regardless of thesize of the property. Large expanses of open(non-forested) habitat are needed to supportBarn Owls. This large acreage of grassland,agricultural fields, etc. does not have to be inone ownership, but a small acreage of suit-able habitat surrounded by forestlands willprobably not attract Barn Owls.

Nest boxes may be erected in different ways.It is important to erect the Barn Owl box orboxes in the way that best suits your needs.

Important Considerations for Placinga Barn Owl Nest Box

• It should be in an area that has lowhuman activity.

• The entrance of the hole should faceaway from prevailing winds.

• Do not place the box above metal vehi-cles because the owl’s fecal material iscorrosive.

• The nest box should not be too high soas to prevent safely inspecting and main-taining the box. A good height is 12 feetoff the ground.

If you have a barn or abandoned silo onyour property, it may serve as an excellentplace to locate a Barn Owl nest box. If theentrance hole of the box is on the inside ofthe barn, the area below the entrance holeshould be free of items that need to be keptclean. A nest box design for barns and silos isprovided at the end of the fact sheet. *Animportant note is that a barn or silo is notneeded to attract Barn Owls. Boxes placed inother out buildings (other than a farmhouse)can also work.

A second possible location to mount a nestbox is on a large tree. The box should be aminimum of 12 feet off the ground. Onepotential problem with tree mounting is thatnestlings and even adult birds may be at agreater risk of predation from opossums, rac-coons, and great horned owls.

Finally, nest boxes may be mounted on a16’x4"x4" pole. This pole should then be putin a 3-foot-deep hole. A bag of concrete(although not necessary) mixed around thepole will provide the pole with good support.Be sure to use a level on two different planesof the pole to ensure the pole is vertically

level. The pole should have a predator baffleor guard placed around it at 4 to 5 feet abovethe ground. This may be in the form of a 3-foot diameter metal cone or a 24-inch widepiece of aluminum flashing tightly wrappedaround the pole. Boxes mounted on polesshould be within 100 yards of a large tree toprovide cover for young after they leave the nest.

You may want to try a combination ofthese different techniques if all or a couple ofthe nest box mounting opportunities exist onyour property.

Monitoring and MaintainingYour Nest Boxes

Before you decide to erect Barn Owl nestboxes, you must first realize that the boxeswill need to be monitored and maintained.Erecting nest boxes is the first step, but moni-toring and maintaining the boxes is equallyas important. Fortunately, Barn Owls do notrequire a lot of attention, but inspecting andcleaning out the boxes will be necessary fromtime to time.

Barn Owls in Maryland may be found nest-ing at any time of the year, although the peaknesting period is between April and July.Nest boxes should be checked once a year inlate fall or early winter. VERY IMPORTANT!You must be as quick and quiet as possiblewhen checking a Barn Owl box. If a femaleBarn Owl is sitting on eggs in the nest, quick-ly and quietly close the box and do not dis-turb the owls again. Checking the nest whilethe female is incubating could cause her toabandon the nest and/or destroy the eggs.Also, never knock on the post to see if birdsfly out. For these reasons, it is important tocheck the boxes only in the fall or early win-ter, which is the least likely time to find BarnOwls in the boxes.

During the nest box inspection, all nestmaterials, feathers, dirt, animal parts, bees orwasps, and pellets should be removed. Youshould always wear a dust mask when clean-ing out any bird house to avoid inhalingundesirable dust and nest parasites. After thiscleaning out is complete, it is advised thatthe box be sprayed with a 2-percent bleach

Hoffman, T. 1997. Using Barn Owls for RodentControl, World Wide Web Publication -http://members.tripod.com/Tommy51/

.Johnsgard, P. A. 1988. North American Owls:

Biology and Natural History. Washington:Smithsonian Institution Press.

Maryland Department of Natural Resources,The Barn Owl: Friend of the Farmer.Annapolis: Wildlife and Heritage Division.

Pimentel, D., Lach, L., Zuniga, R., andMorrison, D., 1999. Environmental andEconomic Costs Associated with Non-indige-nous Species in the United States. Ithaca:College of Agriculture and Life Sciences.

Taylor, I. Barn Owls: Predator-Prey Relationshipsand Conservation. New York: CambridgeUniversity Press.

solution to thoroughly disinfect the box.Never use insecticides inside the nest box.

References

Bendel, P.R. and Therres, G.D. 1990. “NestingBiology of Barn Owls from Eastern ShoreMarshes.” Maryland Birdlife, vol. 46, #4, pp.119-123.

Bendel, P. R., and Therres, G. D. 1992. “BarnOwl diets from Eastern Shore marshes.“Maryland Birdlife, vol. 48, #1, pp. 3-6.

Coleman, J.S., Temple, S.A., and Craven, S.R.1997. Cats and Wildlife: A ConservationDilemma. Madison: Wisconsin CooperativeExtension.

4 5

site, along with available food, Barn Owlsmay be attracted to the area regardless of thesize of the property. Large expanses of open(non-forested) habitat are needed to supportBarn Owls. This large acreage of grassland,agricultural fields, etc. does not have to be inone ownership, but a small acreage of suit-able habitat surrounded by forestlands willprobably not attract Barn Owls.

Nest boxes may be erected in different ways.It is important to erect the Barn Owl box orboxes in the way that best suits your needs.

Important Considerations for Placinga Barn Owl Nest Box

• It should be in an area that has lowhuman activity.

• The entrance of the hole should faceaway from prevailing winds.

• Do not place the box above metal vehi-cles because the owl’s fecal material iscorrosive.

• The nest box should not be too high soas to prevent safely inspecting and main-taining the box. A good height is 12 feetoff the ground.

If you have a barn or abandoned silo onyour property, it may serve as an excellentplace to locate a Barn Owl nest box. If theentrance hole of the box is on the inside ofthe barn, the area below the entrance holeshould be free of items that need to be keptclean. A nest box design for barns and silos isprovided at the end of the fact sheet. *Animportant note is that a barn or silo is notneeded to attract Barn Owls. Boxes placed inother out buildings (other than a farmhouse)can also work.

A second possible location to mount a nestbox is on a large tree. The box should be aminimum of 12 feet off the ground. Onepotential problem with tree mounting is thatnestlings and even adult birds may be at agreater risk of predation from opossums, rac-coons, and great horned owls.

Finally, nest boxes may be mounted on a16’x4"x4" pole. This pole should then be putin a 3-foot-deep hole. A bag of concrete(although not necessary) mixed around thepole will provide the pole with good support.Be sure to use a level on two different planesof the pole to ensure the pole is vertically

level. The pole should have a predator baffleor guard placed around it at 4 to 5 feet abovethe ground. This may be in the form of a 3-foot diameter metal cone or a 24-inch widepiece of aluminum flashing tightly wrappedaround the pole. Boxes mounted on polesshould be within 100 yards of a large tree toprovide cover for young after they leave the nest.

You may want to try a combination ofthese different techniques if all or a couple ofthe nest box mounting opportunities exist onyour property.

Monitoring and MaintainingYour Nest Boxes

Before you decide to erect Barn Owl nestboxes, you must first realize that the boxeswill need to be monitored and maintained.Erecting nest boxes is the first step, but moni-toring and maintaining the boxes is equallyas important. Fortunately, Barn Owls do notrequire a lot of attention, but inspecting andcleaning out the boxes will be necessary fromtime to time.

Barn Owls in Maryland may be found nest-ing at any time of the year, although the peaknesting period is between April and July.Nest boxes should be checked once a year inlate fall or early winter. VERY IMPORTANT!You must be as quick and quiet as possiblewhen checking a Barn Owl box. If a femaleBarn Owl is sitting on eggs in the nest, quick-ly and quietly close the box and do not dis-turb the owls again. Checking the nest whilethe female is incubating could cause her toabandon the nest and/or destroy the eggs.Also, never knock on the post to see if birdsfly out. For these reasons, it is important tocheck the boxes only in the fall or early win-ter, which is the least likely time to find BarnOwls in the boxes.

During the nest box inspection, all nestmaterials, feathers, dirt, animal parts, bees orwasps, and pellets should be removed. Youshould always wear a dust mask when clean-ing out any bird house to avoid inhalingundesirable dust and nest parasites. After thiscleaning out is complete, it is advised thatthe box be sprayed with a 2-percent bleach

Hoffman, T. 1997. Using Barn Owls for RodentControl, World Wide Web Publication -http://members.tripod.com/Tommy51/

.Johnsgard, P. A. 1988. North American Owls:

Biology and Natural History. Washington:Smithsonian Institution Press.

Maryland Department of Natural Resources,The Barn Owl: Friend of the Farmer.Annapolis: Wildlife and Heritage Division.

Pimentel, D., Lach, L., Zuniga, R., andMorrison, D., 1999. Environmental andEconomic Costs Associated with Non-indige-nous Species in the United States. Ithaca:College of Agriculture and Life Sciences.

Taylor, I. Barn Owls: Predator-Prey Relationshipsand Conservation. New York: CambridgeUniversity Press.

solution to thoroughly disinfect the box.Never use insecticides inside the nest box.

References

Bendel, P.R. and Therres, G.D. 1990. “NestingBiology of Barn Owls from Eastern ShoreMarshes.” Maryland Birdlife, vol. 46, #4, pp.119-123.

Bendel, P. R., and Therres, G. D. 1992. “BarnOwl diets from Eastern Shore marshes.“Maryland Birdlife, vol. 48, #1, pp. 3-6.

Coleman, J.S., Temple, S.A., and Craven, S.R.1997. Cats and Wildlife: A ConservationDilemma. Madison: Wisconsin CooperativeExtension.

4 5

Appendix

Parts List1. One sheet of 1⁄2-inch CDX plywood (5

ply).2. One 16 foot 4x4 post (redwood or pres-

sure treated) to extend 12 feet above ground. 3. Four 1-inch L-brackets with eight 3⁄4-inch

No.10 flat-head sheet metal screws.4. Two 41⁄2 -inch by 3⁄8-inch carriage bolts

with nuts and washers for mounting the boxto the post.

5. Two 2x2-inch tight pin hinges withscrews.

6. Two 13-inch 2x2's for spacers.7. One 11⁄2-inch hook and eye for clean out

door.8. Four 31⁄2-inch by 1⁄4-inch carriage bolts

with nuts and washers for top assembly.9. 11⁄4-inch galvanized box nails.10. Paint or stain (light natural wood color

or clear stain).

Note: This nest box design may beinstalled in a tree, on a post, or in a barn orsilo. The diagram specifically shows how toinstall the nest box on a post.

General instructions: All joints must beglued before nailing. Nails should be placed 1⁄4inch from edges, spaced 3 to 4 inches apart. Ifnail does not go in straight, remove with pli-ers before finishing pounding.

Step 1. Cut plywood sheet as shown.Measure, mark and cut entrance hole onfront. Drill four 1⁄2" holes in the bottom fordrainage. Cut 6"-wide clean-out flap from endof one side.

Step 2. Nail back panel to left side, thenturn assembly over and nail front panel toleft side. Insert floor between front and backpanels. Align lower edges and nail throughfront into the floor. Carefully turn assemblyover and nail through back into floor. Insertupper portion of right side between front andback panels. Align upper edges and nailthrough back. Turn over. Again, align upper

edge and nail through front. Nail through leftpanel into floor.

Step 3. Attach hinges to upper edge of flapthen attach to lower portion of right panel.Drill 1⁄8" hole in lower edge of flap and screwin eye. Measure 11⁄2 inches from eye on floor.Mark, drill, and screw in hook. Glue predatorguard to inside of front and to floor. Setassembled box aside for 24 hours to allowglue to dry.

Step 4. Position roof, spacers and sunshield as shown (sun shield is recommendedif the box is placed on a pole in an openarea). Clamp together and drill through allpieces with 1⁄4" bit. Fasten together with 1⁄4"carriage bolts. Position L-brackets on under-side of roof as shown and attach with screwsso that they will fit over the edges of the sideand front panels.

Step 5. Paint or stain all exposed surfaces.

Step 6. Center back of box on one end ofpost with upper edge of box flush with top ofpost. Drill through box and post togetherand attach with 3⁄8" carriage bolts. Position topassembly and attach by screws through L-brackets.

Barn Owl nest box plans reprinted and adapt-ed with permission from Tom Hoffman ofBiodiversity Products.

Additional ResourcesMaryland Department of Natural

Resources, website: www.dnr.state.md.us.

Fact Sheet Reviewers

Joel FloryWildlife Specialist

Utah State Cooperative Extension Service

Glenn TherresBiodiversity Program Manager

Maryland Department of Natural Resources

Robert TjadenRegional Specialist, Natural Resources

Maryland Cooperative Extension

limit their hunting to the darkest hours ofthe night. Barn Owls normally hunt by flyingup and down open grassland or field areaslooking and listening for prey. At times theywill fly against the wind so that they will notfly too quickly, missing potential prey animals.

Why Try to Use Natural PestControl?

When trying to manage rodent popula-tions, it is important to remember that BarnOwls will not remove all rodents from agiven area. That is not how Mother Natureworks. However, Barn Owls are capable ofmaintaining a rodent population at normallyacceptable levels.

There are a few advantages to using BarnOwls for rodent control. First, rodenticides(rodent poisons) that come in the form ofbaits, pellets, or powders will likely costmore money over the long term than erect-ing a Barn Owl box. Certain rodenticideshave the ability to travel up the food chainand harm or kill non-target or even benefi-cial animal species.

The Barn Owl vs. theDomestic Cat for Rodent

Control Research has shown that a Barn Owl

throughout the course of a year will consumeapproximately 3 to 5 times the number ofrodents that a cat consumes. Also, cats areresponsible for killing a large number ofbirds, most of which are not considered pests.A study conducted in Wisconsin suggests thatcats allowed to go outside, whether in anurban or rural setting, are responsible forkilling approximately 39 million birds a year.It is important to note that this figure onlyrepresents the birds killed by cats in the stateof Wisconsin in one year. The national esti-mate for the number of birds killed by catseach year is 465 million.

Barn Owls are part of the natural land-scape, while domestic cats are not nativepredators in North America. Research isshowing that cats are having a profoundly

negative impact on small mammal and birdpopulations around the country. When itcomes to effectively and naturally controllingrodents, the Barn Owl is far superior to thedomestic cat.

Conservation and Status inMaryland

As mentioned earlier, before many educa-tional campaigns regarding the Barn Owlwere conducted across the country, manyBarn Owls were shot and hung out on fenceposts to supposedly deter other owls fromcoming around. If Barn Owls were founddead, but not shot, they often died as a resultof poisoning. Many of the anti-coagulanttypes of rodent poisons available on the mar-ket can be transmitted up the food chain.The owls would, and still do, ingest mice thathave been poisoned and they in turn are poi-soned and become very sick or die.

Today, the Barn Owl population inMaryland is considered to be stable through-out its range, although continued habitatdestruction from development may poseproblems for the population in the future.We may play a vital role in the future of theBarn Owl’s success by providing nesting sitesneeded to ensure a stable population.

Providing Nesting Sites forBarn Owls

Barn Owls will nest in properly constructedand mounted nest boxes. The birds are notconsidered to be finicky and will nest in avariety of places that are dark and normallyelevated at least 12 feet above the ground.

Plans for building a Barn Owl nest box maybe found at the end of the fact sheet.

Barn Owls do not exhibit strong territorialinstincts and will nest relatively close toother Barn Owls if adequate food is present.For this reason, nest boxes may be placed afew hundred yards apart. Research fromCalifornia suggests that between four to sixBarn Owl boxes can be placed in a 50-acrearea. This does not suggest that 50 acres ofland is needed to attract Barn Owls. If theproper habitat is available with a proper nest

6 3

hundred dollars in reduced crop damage andother benefits. This fact sheet will describemany aspects of the Barn Owl including iden-tification, distribution, habitat preferences,food habits, and how to try to attract BarnOwls to your property.

Unfortunately, Barn Owls have not alwaysbeen held with such high regard. Until thelate 1970’s, Barn Owls were often shot bylandowners because they were consideredvermin. Because Barn Owls hunt by night,their ability to control rodents was notknown by the average landowner. As educa-tion regarding the Barn Owl increased, nega-tive actions against Barn Owls decreased.

Barn Owls and all other raptors or birds ofprey (hawks, owls, eagles, falcons, and vul-tures) are protected under the Migratory BirdTreaty Act. The law states that it is illegal tohandle, harm, or harass these birds or theirnests in any way.

IdentificationIt has been referred to as the monkey-faced

owl, ghost owl, and spirit owl. Regardless ofthe name you choose the Barn Owl is defi-nitely unique. The Barn Owl is the onlymember of its family (Tytonidae) in NorthAmerica. It differs from other owls, such asthe great horned owl and barred owl, in threeprimary ways. The Barn Owl has a heart-shape facial disk unlike other owls’ facialdisks that are normally round. It also has acomb-like claw on its middle toe that is notpresent on other owl species. Finally, theBarn Owl has a relatively short and squaretail, where other owls have longer, morerounded tails.

The most common identifying marks ofthe Barn Owl include the bright white underbody and the heart-shaped facial disk. If seenin the field, these two features normally giveit away. Also, if you happen to hear an owl"hooting" at night, it most likely is not a BarnOwl. The Barn Owl does not "hoot" likemany other owls. The owl’s call has beendescribed as a shrill, rasping hiss or snoresuch as kschh or shiiish.

DistributionThe Barn Owl is one of the most widely

distributed raptor species in the world. It canbe found on every continent exceptAntarctica. The bird is also found widelythroughout the United States except for theAppalachian Mountains, northern NewEngland and the northern plains areas.

In Maryland, Barn Owls can be found inmost every county except for far westernMaryland. Concentrations of nesting BarnOwls have been identified in several countiesin central Maryland and the Eastern Shore.

HabitatThe habitat preferred by the Barn Owl is a

mixture of grasslands, groves, farm fields,and pastures. The birds prefer to roost in oldbuildings, silos, and of course barns. BarnOwls favor low arable land as well as marshesnear the Chesapeake Bay. The birds haveeven been found nesting in hunting blindsalong marshes of the Eastern Shore.

Barn Owls are traditionally cavity nesterswhich means they prefer to raise their youngin a large hole in a tree or in an appropriatespot in a barn or silo. Removal of older treeshas created a limited number of cavities fornesting Barn Owls. For this reason, we canencourage Barn Owls to use nest boxes, ifproperly constructed and placed around suit-able habitat, that mimic their traditionalnest sites.

Food HabitsBarn Owls eat a wide variety of prey.

However, while studies show their diet maybe diverse, they tend to concentrate themajority of their hunting efforts on just a fewspecies. Small mammals, including mice,voles, and shrews make up the largest portionof their diet. Other food items taken less fre-quently include bats, birds, lizards, andinsects. It is important to note that BarnOwls do not eat chickens.

Barn Owls normally start to hunt arounddusk or even before dusk at times. If greathorned owls (a major predator of Barn Owls)are known to be in the area, Barn Owls may

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Introduction

The Barn Owl is a creature that conjuresimages of mystery and intrigue in many peo-ple and for good reason. This animal is oneof the most secretive and highly effectivenighttime predators in the world. The effec-tiveness of the Barn Owl in controllingrodents, including mice and voles, is unri-valed in the animal kingdom.

The value of one Barn Owl to a farmermay be worth its weight in gold. It hasbeen estimated that during a Barn Owl’slifetime (assumed at 10 years) it would

eat approximately 11,000 mice.These 11,000 mice would have each

eaten approximately 10 percent oftheir weight in food per day.

These11,000micemight

have con-sumed or

fouled an esti-mated 13 tons of

growing crops, seeds, andgrain in their lifetime. For thisreason, every Barn Owl living

on a farmer’s property isclearly worth several

Fact Sheet 795

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The Barn Owl: Friend of Agriculture and Communities

by

M. Allan DalyExtension EducatorBaltimore County

Issued in furtherance of Cooperative Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture, University of Maryland, CollegePark, and local governments. Thomas A. Fretz, Director of Maryland Cooperative Extension, University of Maryland.

The University of Maryland is equal opportunity. The University’s policies, programs, and activities are in conformance with pertinent Federal and State laws and regulations onnondiscrimination regarding race, color, religion, age, national origin, sex, and disability. Inquiries regarding compliance with Title VI of the Civil Rights Act of 1964, as amended;Title IX of the Educational Amendments; Section 504 of the Rehabilitation Act of 1973; and the Americans With Disabilities Act of 1990; or related legal requirements should bedirected to the Director of Personnel/Human Relations, Office of the Dean, College of Agriculture and Natural Resources, Symons Hall, College Park, MD 20742.

The Barn Owl: Friend of Agriculture and Communities

P2002

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