Posts Tagged ‘Biology’

Published in Proceedings at the National Wildlife Rehabilitation Symposium—1984.

Common Barn-Owl Restoration in Iowa

By  Bruce L. Ehresman

Common Barn-Owl Restoration in Iowa

Bruce L. Ehresman

Iowa Conservation Commission, Wildlife Research Station

Boone, IA  50036

Abstract:  One goal of the Iowa Conservation Commission’s Nongame Program is to increase the population of the Common Barn-owl, an Iowa endangered species. Reasons for restoration include its economic value as a destroyer of grain-eating rodents, its aesthetic value to humans, and publicity for the Nongame Program.

The Iowa Conservation Commission acquires barn-owls used for restoration from other rehabilitation centers and zoos in coastal states where the owls are abundant. We use these owls either for captive breeding at the Wildlife Research Station near Boone, or for placement at selected release sites, primarily in southern Iowa. We choose release sites from areas volunteered by the public, using evaluation criteria we developed. At each release site, commission personnel enclose a section of a building to contain the owls for gentle release. Barn-owl nest box construction in release site areas is promoted. Nearly 40 boxes were erected in 1983. We place barn-owls as mated pairs, pairs with young, or groups of immature.

In 1983, we banded and released 12 adult and 46 immature barn-owls using gentle release methods. Media coverage of restoration efforts has resulted in strong public support, evidenced by Iowa’s income tax refund Checkoff participation.

Barn-owls released in 1983, and future releases, will augment Iowa’s remaining breeding population, and nest boxes erected will re-create needed nest sites.

The Common Barn-owl, as most birds of prey, has been persecuted since it first came into contact with humans. It has been the victim of random and injudicious shooting, trapping, and poisoning. Most tragically, its habitat, including critical nesting sites, has been destroyed because of human ignorance in the pursuit to “improve” our way of life on this planet. The Iowa Conservation Commission (ICC) has embarked on a restoration program to change this unjustified public attitude and to increase the population of the Common Barn-owl, an Iowa Endangered species (Roosa 1977).

DISTRIBUTION

The Barn-owl family, Tytonidae, has a worldwide distribution. It consists of eleven living species and approximately 35 subspecies. Only one of these subspecies, Tyto alba pratincola, is found throughout North America. Populations in the United States are chiefly coastal, decreasing northwards. The Barn-owl is considered a rare, permanent resident of Iowa. Because it is intolerant of cold climates (Bunn et al. 1982), it rarely breeds in the northern part of the state. Most recent sightings indicate it is most numerous in the grassland areas of the south and west portions of the state.

ECONOMIC VALUE

Before European settlers arrived, Barn-owls nested primarily in the hollow cavities of old sycamores and cottonwoods. With the cutting of these cavity trees, the Barn-owl adapted to the use of man-made structures for nesting. It also switched from eating mice and voles of native grasslands, to feed on the rats and mice that were attracted to stored grain on farmsteads. According to Lewis Walker (1974), a Barn-owl authority, single owls saves the State of California between $20 and $50 annually in its predation on pocket gophers, where pocket gophers and ground squirrels cause an estimated crop loss of 10% each year. Add to this its services in destroying voles and mice (its preferred prey), and these owls certainly do have a positive economic impact.

STATUS

It is unfortunate that a species so beneficial to humans is becoming so rare in the Midwest. Presently, the Barn-owl is listed as Endangered not only in Iowa, but also in Missouri (Wadell and Crawford 1982), Illinois (Becker 1978), and Wisconsin (Petersen 1979), and is considered threatened in Michigan (Taylor 1978).

LIMITING FACTORS

Decline of the Barn-owl can probably be attributed to a combination of factors, some interrelated. Loss of habitat, especially loss of nest sites, may be an especially important factor. Farmers have bulldozed vacant farm buildings and old hollow trees that once provided nest and roost sites, to prepare more land on which to grow cash grain crops. Modern clean-farming practices and the elimination of hay and pasture ground, prevalent on farms as recently as the mid 1960’s, has reduced habitat of the Barn-owl’s small-mammal prey.

Pesticide and rodenticide use undoubtedly have negative effects on the predator Barn-owl. Use of pesticides, particularly the chlorinated hydrocarbons, was probably most detrimental to Barn-owl populations 15 to 20 years ago before stringent regulations banned, or at least regulated their use (Bunn et al. 1982).

In Iowa, there are at least two predators that exploit the Barn-owl. Raccoons inhabiting old farm buildings harass and predate nesting Barn-owls. In the past few decades, raccoon numbers have increased in Iowa (Andrews et al. 1982) and adjoining states such as Wisconsin (Petersen 1979b). Competition with and predation by Great Horned Owls may also be a limiting factor (Wayne 1924).

Certainly collisions with automobiles, trains, power lines, etc., take a toll on Iowa’s Barn-owl population. From 1981 to 1983, 4 of 6 reported Barn-owl mortalities in Iowa were attributed to collisions.

Severe winter weather also affects survival of Barn-owls. Stewart (1952) indicated Barn-owl survival in its northern range was more influenced by snow cover amount than low temperatures. Petersen (1979a) found that snow cover depth of 10 cm or more provided cover for small mammals and protected them from owl predation in southern Wisconsin, which corresponds in latitude to northern  Iowa. Since the Barn-owl maintains the lowest body fat reserves (5.5%) of all owls examined by Piechocki (1960), it seems likely the Barn-owl cannot survive more than 3 to 4 days without feeding (Stewart 1952), especially during periods of sub-zero temperatures. Two of 4 wild Barn-owl mortalities reported in Iowa in 1983 were attributed to starvation during severe winter weather.

RESTORATION

1. States of Development

Since Iowa’s Barn-owl has been decreasing for several decades, and since the Barn-owl breeds readily in captivity, recommendations were made by Iowa’s State Ecologist, Dean Roosa (1977), to embark on a captive breeding and restoration program. Common Barn-owl restoration in Iowa began as an offshoot of the ICC’s raptor rehabilitation project at the Wildlife Research Station (WRS) near Boone. From 1960 top 1980, the facilities were used to hold birds and mammals for the state Wildlife Exhibit. Funding provided by hunting and fishing license fees allowed a wildlife rehabilitation project to begin in the late 1970’s, when Iowa’s first nongame biologist was hired. A reduction in State expenditures forced the closure of the Wildlife Exhibit in 1980.

Raptor rehabilitation at the WRS still continues, but since the fall of 1982, our main emphasis is on captive breeding, rehabilitation, and restoration of the Common Barn-owl. Reasons for restoration include its economic value as a destroyer of grain-eating rodents, its aesthetic value to humans, and publicity for the Nongame Program. Funding is now derived from an Iowa income tax refund Checkoff initiated in tax-year 1982 for Iowa’s Nongame Program.

B.    Source

Since it was virtually impossible to locate native Barn-owls for captive breeding, we had to look to outside sources. We contacted successful breeders mentioned in International Zoo Yearbooks, and publicized our project in several veterinary journals and magazines. Response was good. So far, we have received Barn-owls by air-freight shipment from rehabilitation centers in zoos in Washington, Oregon, California, Louisiana, and South Carolina. We paid air-freight costs, and during 1982-83 we received 71 Barn-owls at an average cost of about $13 per owl. We use these owls either for captive breeding at WRS facilities or for placement at selected release sites.

C.    Housing

Housing facilities at the WRS include a 14’x80’ wooden building divided into 8, 10’x7’8’ (LWH) and 4, 10’x4’x8’ pens, and a 40’x60’ steel shed containing 8, 8’x7’x8’ breeding pens connected to exterior 20’x8’x8’ flight chambers. Pens are wood framed, with walls of corrugated fiberglass panels and olefin netting. Most pens are visually separated by solid partitions to allow breeding Barn-owl pairs privacy. We place nest boxes in each pen, as well as various diameter tree branch perches. Metal flashing or smooth fiberglass skirting, two feet height, placed around the perimeter of each pen retains live mice for the owls to prey upon. Small pea gravel covers floors to facilitate cleaning. We clean pens about every three weeks, except when hens need minimum disturbance during nesting.

D.    Feeding

The diet and health of captive Barn-owls requires continuous attention. We feed routinely six days a week and fast one. Food is placed on wooden pallets, and uneaten food is removed daily. During winter months, heated food trays, modeled after those of Katherine McKeever (1979), keep the owls’ meals from freezing. We disinfect feeding pallets periodically to ensure harmful microorganisms are not transmitted to or between the owls.

Diet consists of a prepared Birds of Prey diet[1], day-old cockerel chicks culled from a local hatchery, and laboratory mice acquired from the National Animal Disease Center and Iowa State Diagnostic Laboratory in Ames. We feed these three different food items on a rotational basis to assure a balanced diet for the owls. Day-old chicks, deficient in calcium, are powdered with bonemeal before begin fed, and other supplemental minerals and vitamins are added to the diet when necessary.

E.    Medical

We treat sick or injured birds according to recommendations made at the Iowa State University’s College of Veterinary Medicine in Ames. They provide treatment and diagnoses at a teaching discount, since we provide some hands-on experience with wildlife species for students training at the clinic. We also isolate new birds brought into the facility to prevent the introduction of pathogenic organisms to or from other birds. Our personnel keep records on each owl’s health and history.

F.     Captive breeding

The ICC hopes to increase wild Barn-owl populations by releasing breeding pairs with young, and fledglings from other rehabilitators, as well as from our captive breeding pairs. All owls received from other sources are at least temporarily held at WRS facilities. Permanent cripples, human imprints, and owls that have been held several years in captivity comprise most of our captive breeders. We pair the owls for breeding according to size, temperament, age, and body condition; and place them together using methods suggested by McKeever (1979). Owls of similar sizes and temperament are our most successful breeders.

G.    Release site suitability

Before Barn-owls can be placed, release sites must be selected. We choose release sites primarily from areas volunteered by the public. After reading about this project in the newspaper, cooperators, who feel they have adequate hack sites and are willing to feed captive Barn-owls, notify Iowa’s nongame biologist. We send volunteers a “Barn-owl Release Site Preliminary Evaluation” form to complete and return. They complete this form with an aerial photograph of the proposed site, obtained from their local ASCS office. We evaluate and rate each returned form and choose release sites from those forms indicating the best habitat for Barn-owls.

Evaluation of the proposed release site includes the area within a one-mile radius of the release site structure (roughly 2,000 acres), based on the owls’ hunting behavior. The release site structure must be undisturbed, and able to be made “owl tight” with a few hours’ work. Criteria for choosing a release site are as follows:

Positive aspects –

(1)   Abundant grassland (pasture, hayfields, waterways, roadsides)

(2)   Timber in large, continuous tracts (if present)

(3)   Several people willing to feed and care for owls

(4)   Other undisturbed nest sites available nearby

Negative aspects –

(1)   Large amounts of cash grain crops

(2)   Resident Great Horned Owls present

(3)   Nearby use of rodenticides

Basically, we are looking for areas with a large proportion of permanent grassland, which have several undisturbed potential nesting sites (Bunn et. Al. 1982), and few Great Horned Owls present. Dense grasses provide good habitat for small mammals which the Barn-owl prefers as prey. Old vacant buildings or large hollow trees provide adequate nest sites. Since Great Horned Owls have been known to prey upon Barn-owls, we prefer to release our owls where such predators are not numerous. Most release sites are in areas where Barn-owls are present, or were present, within the last 5 to 20 years.

H.    Release site preparation

Once a release site with a suitable confinement structure is selected, the site must be prepared for the owls. Ideally, we prefer to allow confined owls an entire building or silo in which to fly about. This is not always possible. Usually, we are at least able to allow the owls the freedom of an entire barn loft. We close all exits, using boards or olefin netting. We then line a 16-inch square nest box, with a six-inch diameter entrance hole, with two inches of wood chips, since Barn-owls are not known to construct nests. Next, we attach this box near the top of each structure in a place that is as nearly predator-proof as possible. In silos, we place the nest box approximately two-thirds of the height above the floor (Marti et al. 1979). We supply large stock tanks to the enclosures containing fledgling owls. Live mice released into these tanks allow young Barn-owls the opportunity to learn to catch their prey before release to the wild.

I.     Placement

Barn-owls released in 1983 were placed as mated pairs, pairs with young, and groups of immature. We supplied cooperators with meat to feed the owls, and they fed the confined owls daily and monitored food consumption. Cooperators continued to feed the owls after their release until the birds were self-sufficient.

In 1983, we place 4 mated pairs (normally second-year owls) at release sites, prior to the main breeding season. In our captive Barn-owls, this has been from January through March. The hen from one pair appeared to be nesting in hay on the barn floor when she was not seen for several weeks. Since the paid did not nest successfully, and because cooperators could not fee the owls through the winter months, the pair was captured and returned to the WRS facilities prior to winter. A second pair remained captive for almost an entire year and just recently began courtship. Two captive pairs did nest after 2 months and 5 months, respectively, and fledged 5 young each. We released one of these pairs with young, but held captive the second pair with young over winter. Since these young fledged in late fall, we felt gentle release in early spring, rather than winter, would increase their survival chances. Normally, when the owlets fledge and catch live mice proficiently from the stock tank, it is time for gentle release. We open the structure so the occupants can hunt natural prey in the area near the release site. By allowing the owls to raise young at a site, we hope a bond will be established, so that either the nesting pair or their young will return to nest again in the future.

A second method of placement, which we feel is successful, is placing pairs with young. This method works well at sites where cooperators do not wish to feed captive owls daily for more than 2 or 3 months. During 1983, 5 Barn-owl pairs were placed with their 176, 3- to 4-week old young, which they hatched at the WRS.

Originally, we intended to allow parent owls freedom to hunt for natural prey outside the structure when the young are about one month old. Theoretically, the presence of the young will draw the adults back to the barn. Jane Ratcliffe (1979, cited by Bunn et al. 1982) of England, experienced good success using this method with Barn-owls. Unfortunately, the first time we tried this strategy, both adults vacated and did not return to feed their young. Our cooperator was then faced with the problem of feeding 5 very hungry owlets. It should be mentioned that we tried this method with a pair of Barn-owls and young that we moved to the site only several weeks before. With the remaining pairs, we used the same release techniques described for mated pairs – waiting until the young fledged before allowing freedom for the entire family unit. In 4 cases, this included foster young.

When the owlets of 4 family units were 6 to 8 weeks old, we added 8 more young of the same age to the broods, 2 owlets to each foster family. Four of these were WRS hatchlings, and 4 were from California. We experienced no problems with fostering young, as long as all young involved were nearly the same age.

Besides the Barn-owl family units, immature Barn-owls were also gently released. We held these owls captive at the release site for only 4 to 5 weeks. They were WRS fledglings and young owls received from California and Louisiana. To discourage inbreeding, we placed Barn-owls of different parentage at release sites of close proximity (40 miles). Volunteers hacked 4 immature owls at each of 4 sites.

In 1983, a total of 12 adult and 46 immature Common Barn-owls were banded with lock-on U.S. Fisheries and Wildlife Service leg bands and gently released. We hope this number of released owls is significant enough to have beneficial effects on the future Iowa wild breeding population. Our goals will be met when we know of at least 5 self-sustaining Barn-owl populations in Iowa habitats.

J.     Follow-up

We feel it is important to monitor the Barn-owls, even after release. Post-release monitoring is presently conducted primarily by volunteer cooperators. We ask these cooperators to keep records of post-release activity, including feeding and artificial nest box use. To ensure released owls of other roost and nest sites, at least one other nest box is erected in a vacant or little-used structure within a one-mile radius of the release site. As many as 10 nest boxes have been constructed and put up by concerned citizens in any one release site area. During 1983, nearly 40 nest boxes were erected in release site vicinities. Because our Nongame staff lacks time and manpower to monitor every nest box placed, we do appreciate the release site cooperators, County Conservation Board members, and other ICC personnel who voluntarily monitor nest box use.

Since loss of suitable nest sites is a factor in the decline of the Common Barn-owl, the ICC is promoting the use of artificial nest structures to increase our wild population. In Utah, 30 nest boxes were used by 24 barn-owl pairs to produce 154 young in 2 years (Marti et ala. 1979). We make available to the public Barn-owl life history brochures which include nest box construction and erection instructions. Many citizens have already used these instructions to build and place nest boxes.

K.    Media coverage

Media coverage at Barn-owl placement sites and about the Barn-owl restoration program has been instrumental in educating the public, as well as generating public support. Major Iowa newspaper and television stations have sent personnel to do stories at release sites with very short notice from us. Local newspaper coverage of releases has also been excellent. A number of radio stations have interviewed ICC personnel about the program. Such coverage has promoted statewide response from citizens who want to become involved with the Barn-owl restoration program. Undoubtedly it has also increased donations to the Nongame Iowa income tax refund Checkoff which funds our program.

FUTURE

Plans for 1984 include placement of 7 Barn-owl breeding pairs in January, several pairs with young in April, and approximately 20 fledglings during summer. Also, in 1984, we hope to place radio transmitters on 3 breeding pairs and 10 fledgling Barn-owls to monitor habitat use, early dispersal movements, and mortality. A graduate student from Iowa State University will be involved full time on this aspect of the program.

CONCLUSION

The success of Iowa’s Common Barn-owl restoration program is greatly dependent on public education and involvement. Much public interest has already been generated, and we need to channel this interest into involvement with building and erecting nest boxes, as well as monitoring these boxes for Barn-owl use.

It is also important that we cooperate with Barn-owl restoration projects in neighboring states such as Missouri and Nebraska. We can learn from each other’s failures and successes, and it is probably only a matter of time before a Barn-owl banded in Iowa shows up in a nest box in Missouri, or vice versa. Cooperation is certainly the key to this program’s success!

ACKNOWLEDGEMENTS

I thank Iowa’s Nongame Biologist, D. A. Newhouse, who initiated the Barn-owl restoration program, and who provided assistance in the final draft of this manuscript. I extend special thanks to my wife, M. Ehresman for being the main editor of this paper as well as providing field assistance and constant moral support. I thank S. Monen for typing this manuscript and for her secretarial work related to the restoration project. I also thank L. Crim and R. Dietz for their field assistance and dedicated care of captive breeding owls. I am grateful to Dallas Center Hy-Line International, the National Animal Disease Center and Iowa State Diagnostic Laboratory, located in Ames, for contributing their excess chicks and mice to supplement our captive owl food source; and I thank R. Lindahl and G. Crim for providing laboratory mice delivery service. I am especially thankful to the following cooperators who provided release sites and/or captive owl care, and whose efforts made Barn-owl releases possible: B. and N. Bakehouse, R. and F. Cooper, C. and K. Froyen, L. and M. Hardin, I. Hardt, C. Hensley and Cass County Conservation Board staff, L. and C. Inman, H. Jensen, L. and N. Link, M. Moe, J. and B. Sabin, E. and M. Schlueter, and B. and J. Wilson. Also, a special thanks goes to R. Minthorn who contributed 10 nest boxes for owls released in Mills County. Finally, I wish to thank the people who have contributed to Iowa’s Nongame income tax refund Checkoff, which funds this project.

LITERATURE CITED

ANDREWS, R. D., J. L. HANSEN, and B. R. OHDE. 1982. Furbearer harvest survey. Iowa Conserv. Comm. Study no. 19.

BECKER, C. 1978. Endangered and threatened wildlife. Ill. Dept. Conserv. 1-4.

BUNN, D. S., A. B. WARBURTON, and R. D. S. WILSON. 1982. The Barn Owl. Vermillion, South Dakota, Buteo Books.

MARTI, C. D., P. W. Wagner, and K. W. DENNE. 1979. Nest boxes for the management of barn owls. Wildl. Soc. Bull. 7(3):145-148.

MC KEEVER, K. 1979. Care and rehabilitation of injured owls. Ontario, Canada, W. F. Rannie.

PETERSEN, L. R. 1979a. Ecology of Great Horned Owls and Red-tailed Hawks in Wisconsin. Wis. Dept. Nat. Resour. Tech. Bull 111:1-95.

_______. 1979b. Status of Barn Owls in Wisconsin. Wis. Dept. Nat. Res. Rep. 1097:1-11.

PIECHOCKI, R. 1960. Uber die winterverluste der schleiereule. (Tyto alba). Vogelwarte 20:274-280.

RATCLIFFE, E. J. 1979. Fly high, run free. London.  Reference not available, cited from Bunn et al. (1982)

ROOSA, D. M. 1977. Endangered Iowa birds (an annotated list of endangered, threatened, extirpated or “status undetermined” birds of Iowa). Iowa Conserv. Comm. Spec. Rep. of Preserves Board, no. 4:1-25.

STEWART, P. A. 1952. Dispersal, breeding behavior, and longevity of banded Barn Owls in North America. Auk 69:227-45.

TAYLOR, S. M. 1978. Michigan’s endangered and threatened species program. Mich. Dept. Nat. Resour. 1-35.

WADDELL, W., and W. C. CRAWFORD, Jr., 1982. Barn Owl recovery program – Missouri and the Midwest. Pp. 74-80 in wildlife rehabilitation (P. Beaver, ed.). Smithtown, New York, Exposition Press, Inc.

WALKER, L. W. 1974. The book of owls. New York, Alfred A. Knopf, Inc.

WAYNE, A. T. 1924. A death trap to the American Barn Owl (Tyto pratincola). Auk 41(2):342.

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[1] (Product of Central Nebraska Packing Company of North Platte. Mention of trade names does not imply endorsement by the ICC.)

Operation Barn Owl Nest Box

_{By “Love’s Wildlife Control”}

Picture 2 Tim Love and Lloyd Phillips with the first Owl Nest Box installed on Kay Harsin’s Farm.

The idea of using Barn Owls to reduce rodent populations is not a new idea, BUT it is new to “Love’s Wildlife Control”. In March of 2009, a visitor to my booth at the “Hawkeye Farm Show” in Cedar Falls, Iowa mentioned he was doing this. Intrigued, I began researching Barn Owls and contacting people who are experts. I am inspired and excited about the possibilities of this project. I am happy to be able to help the Barn-Owl and provide a simple and affordable way to those who are interested in the possibilities of using Barn Owls for natural rodent control. This project is about helping restore Barn Owl numbers in Iowa. Rodent control is merely a by-product from achieving our goal.

Why Barn Owls? Well first, Barn Owls are endangered in Iowa and they need our help. Second, the Barn Owls’ diet consists almost entirely of rodents. The vole is number one on their diet followed closely by shrews, mice, rats and gophers. What this means to you is 24/7 rodent control on your property 365 days a year. Barn Owls are the best employees that the landowner can have as they do not need to be paid and they are on duty every day of the year. They ask for nothing but to be left alone and to be protected from predators and the weather with a suitable nest. Third, this is a natural control measure which means you can avoid using most rodent baits, saving you time and money while protecting the environment. Fourth, keeping rodent numbers in check saves excessive damage to your property.

What do you mean by “control”? When I refer to control I do not mean total elimination of rodents. I do not mean that if you put up these boxes that it will fix a hay field that is infested with gophers. I do mean that having a predator that specializes in rodents (the Barn Owl) is an asset to you and your property. Every rodent that the Barn Owl consumes is one less that affects you. Nature is checks and balances and I believe that the Barn Owl helps to maintain the balance.

Why are Barn Owls struggling? Loss of prey habitat is one problem, but in my line of work I see plenty of prey for the owls. Historically Barn Owls have used old hollow trees to nest in. Clearing land for agriculture eliminated many of these old trees. As their name implies, the Barn Owls seek cavities in old buildings like barns to make nest sites, but today many of the old buildings and barns have been replaced by metal buildings that do not allow the owls access. Predators such as the Great Horned Owl and the raccoon make restoring Barn Owl populations very difficult. Nearly every hollow tree or old barn suitable for Barn Owl nesting in Iowa has a few raccoon living there. With few safe nesting areas and large open fields void of large hollow trees, the few Barn Owls we do have are extremely limited in their reproductive capabilities and greatly exposed to the attacks of the great horned owl.

What do we do? The Barn Owl is a very “wimpy” bird which is proven by its high mortality rate, but Barn Owls off-set this by being very prolific breeders. They are capable of breeding throughout the year and can have two broods a year. Each brood may have four or more young. I feel that since they are so prolific and given that they have enough prey available here in Iowa, the only thing that we can logically do is to re-create the missing nesting areas that provide protection from predators-and leave the rest up to the owls.

How do we get started? A good place to start is by installing free-standing nest boxes at least 10 feet high and located away from the larger timber areas that are known to be hangouts for the Great Horned Owl.  One box for every 20 to 40 acres is a good number to strive for. We must remember that the prolific Barn Owl will produce many young and these young will need a safe place to spend their day and eventually raise young of their own. ““Love’s Wildlife Control”” encourages you to put up two nest-boxes (but is not required) initially as more can easily be added at a later time.

What habitat is best? In Iowa we have great habitat for the Barn Owl: pastures, CRP, alfalfa fields, vineyards, terraces, abandoned farms, feedlots, active farms, fence lines, ditches, waterways, grass headlands, etc. Many of these areas are virtually void of trees suitable for the reproduction of Barn Owls but are full of prey for the Barn Owl. Free-standing nest boxes in these areas offer them great protection and a reliable food supply. Typically, Barn Owls do not hunt in the immediate area of their nests. Spacing nest boxes on opposite sides of the property allows the owl hunting areas to overlap.

How do I know I’ll get Barn Owls? There is no guarantee!!! The one thing I feel certain about is that if you don’t put the boxes up you will NOT have them thriving on your property. The experts have told me that some of their own boxes have been up for ten years and have yet to have an owl live in them. But the possibility is there for them to take up residence because the boxes are up and available. In other words, you can’t win if you don’t play, just like the lotto.

Picture 3 The second box is about 400 yards from the first. This large pasture is surrounded by terraced fields  with lots of rodents for the Barn Owls. This particular pasture has 5 boxes with 2 more  close by. Now we WAIT!!!

Why so many boxes? When researching these amazing birds we notice that when the first brood is about half grown the female will naturally move off and begin laying a second clutch of eggs (if a nest site is available). The male is left to feed the “teenaged” youngsters until they can hunt on their own. This leads me to believe that one or two nest boxes are just not enough.  More boxes can easily be added in the future. Barn Owls are not territorial and it is possible to have many females raising young in a small area, such as within 200 yards of each other. It is also possible for one male to have two females laying eggs; given there is enough nesting areas available.

How many rodents do they eat? The numbers are quite staggering and hard to believe. Just one pair, brooding young, account for literally thousands of rodents from your area annually. Having read many websites the answers vary, but in general, an adult owl will eat one a night. But, when a pair is feeding a family, each owlet needs between three and five apiece. For a brood of four young we can expect every night at least 15 rodents will disappear from your property or 105 a week. If we multiply105 a week by the 10 weeks that it takes for the young to fledge, it is logical that 1,050 rodents will be gone!!!  If we can get this pair to brood another time on your property, we could double this for the year which is 2,100; in this figure, this is only the rodents fed to the young, and not  rodents eaten by the parents or by the first brood that are now hunting on their own.

Will the Barn Owls control pocket gophers? Pocket gophers are rodents and while Barn Owls will prey on them readily, the largest pocket gophers of Iowa are just too big for the Barn Owl to swallow whole. During dispersal, the time that the young pocket gophers are being driven from their mother’s tunnels, Barn Owls can eliminate many as young/small gophers are just the right size for the Barn Owl. To answer the question, YES, they do control pocket gophers because the dispersing young pocket gophers are how pocket gopher problems spread.

Do Barn Owls prey on pheasant, quail, and songbirds? I say NO because first, the Barn Owl only kills what it can swallow whole and because nearly 100% of its diet is small rodents. Second, the Barn Owl is a nocturnal hunter meaning it only hunts at night. Third, the Barn Owl hunts by sound and most birds roost at night and are sleeping quietly.

Where is the Operation Nest Box money going? Donations are greatly appreciated and all money generated from donations and owl nest box sales is invested directly back into this project. I have researched and consulted with many experts on the subject of nest boxes. My goal is to build a nest box that is simple, long lasting, and well suited to the Barn Owl. Box dimensions are set to minimize construction waste, maximize usable owl space, and protect the owls from the weather and predators. Boxes are erected on 16’ 4X4 posts in a fence line or on a terrace. The time and labor installing the nest boxes are volunteered but fuel charges will be applied. You are welcome to call and order a box and then pick it up if interested in doing the installation.

Picture 4 Freestanding boxes include sunshade, 2X6 post with coon guards, and mounting bolts.

Thank you for your interest in the project. The nest boxes are $70 each which includes the 4X4 mounting bracket.  I hope to erect some boxes on your property soon. If you would like to donate to the nest box project feel free to send a check and a note explaining such. If you see a Barn Owl, which is known by its white dish shaped face, please call and let us know. All information is useful and needed for us and them to succeed.

*For more information on the fascinating Barn Owl, please just type in “Barn Owl” into your internet search bar and browse the many links available. Here are three of my favorites.

http://members.tripod.com/~Tommy51/aboutbarnowls.html

http://home.earthlink.net/~wildwingco/id3.html

http://www.iowadnr.gov/wildlife/privatelands/barn_owl.html

I would like to thank all of those currently involved in the planning of this venture. First, I want to thank Lloyd Phillips a retired science teacher from Knoxville who I was a student of and am still today. Without Lloyd’s love of woodworking and his generous donation of the use of his wood shop, this project would not be possible. Lloyd has a long-standing track record of practicing good conservation efforts by creating wildlife habitat. He has purple martin houses, an Osprey nest, wood duck boxes, and song bird houses and feeders. Thanks Lloyd!!!

Second, I want to thank Bruce Ehresman from the Iowa Department of natural Resources. Bruce has been involved in Barn Owl research for many years with the IDNR. He has answered a lot of questions from me and makes himself available should I ever (and I will) have more. Thanks Bruce!

Third, I want to thank John Schuster whom owns “The Wild Wing Company” in California. John has a wonderful website that is very informative. John is a raptor expert and has sold and installed countless owl boxes and raptor perches in California vineyards and alfalfa fields. Thanks John for taking the time to talk and for the information on Barn Owl nest boxes.

Fourth, I want to thank Bert Kersey of Fallbrook, CA. Bert has a video called “Backyard Barn Owls” that is very informative and entertaining. I have never visited with him but appreciate the time and effort that he put into his video. His work has been a great help to the Barn Owl and those interested in maintaining them. To order the video go to http://www.barnowlvideo.com/video.html.

Lastly, I would like to thank YOU. Thank you for your interest and taking the time to learn about the Barn Owl, reporting to us your Barn Owl sightings and/or ordering your own Barn Owl nest-boxes. Without people creating homes for the Barn Owl, restoring their numbers to a stable level would probably never happen.

Best Regards,

Tim Love owner of

“Love’s Wildlife Control”

**”Love’s Wildlife Control” believes in supporting local businesses. All lumber for constructing the Barn Owl Nest-boxes is purchased at Spahn and Rose Lumber, of Knoxville, IA. Phone #641-842-2146

Steel for the brackets is cut, punched and bent by Isley Welding and Repair in Knoxville, IA. Phone #641-842-5525

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