Honey Bee Removal In Iowa

Loves Wildlife Control receives many calls every year for problems related to swarming honey bees or honey bees needing to be removed from inside of buildings such as in attics, walls, soffits, chimneys, etc. Loves Wildlife Control does not handle bee problems BUT…. has recently found someone that DOES!!!!

Meet Todd McQueen of Pella, IA. Todd is a member of the Iowa Honey Producers Accociation and maintains a few hundred active hives in the area. He has been doing bee removal for at more than three years now and has handled most situations that bees could inhabit such as brick homes, silos, even removing bees from homes as young as 1 year old. Todd says bees especially love the small opening  above the soffits. Todd’s main work area in Iowa is south of I-80 across state but he will go anywhere if you are willing to pay the extra fee required for outside the area. His fees are subject to mileage and the access to the bees. His services remove the bees and hive only. He says that if the honey is not removed from the building more bees will move in and take over the hive. Todd has a bee vaccum for bee extraction then the crew many times must open up the wall to expose the hive for its removal. Todd and his crew do not repair the buildings after the hive has been removed. The customer must then hire their own carpenter to put the house or building back in order.

Call Todd McQueen at 641-629-0192 for a quote.

Loves Wildlife Control offers the plans to build Barn Owl Nest Boxes just like ours. Our Goal is to get many nestboxes put up in Iowa and to get as many people aware and involved as possible. It is our vision that in 5-10 years sighting a Barn Owl in Iowa will not be a rare thing.

For plans send $5 and a SASE to:

Barn Owl Nest Boxes, Gopher Control or Just Another Gimmick??

I recently read an article in a well respected vineyard and winery publication that featured barn owl nest boxes.  In the article the author speculated that not only will a healthy population of barn owls eliminate a gopher problem but they’ll also greatly reduce the need for pesticide use in the vineyard.  By pesticides, the author was actually inferring rodenticides, not insecticides or fungicides-although it was a pretty broad statement.

I refuted this claim by writing a letter to the editor and got an interesting response from an individual in Pennsylvania who is much more well versed in population dynamics than I am.  This response, combined with the empirical data we’ve collected dealing with growers over the years leads me to ask the question, are barn owl nest boxes really that effective for gopher control or are they just another gimmick.

Rex Marsh asserted years ago that promoting barn owls to control rodents was a mistake. (Sept. 1998 The Probe) In fact, the title of the article was “Promoting Barn Owls to Control Rodents is Deception”.  Rex’s point was that not only will barn owls not control rodents, but the growers belief that they may is detrimental overall to the cause of rodent control because the individual will let the rodent population explode, while vainly hoping for a biological solution, and eventually have to use significantly more rodenticides to bring the problem into balance than if proper measures had just been used initially.

Rex is a pretty well respected guy-I mean he knows more than, well, anyone, in most people’s opinion, when it comes to rodent control.  Few people have made a career of teaching other people how to kill gophers.  Rex has-and is one of the most respected people in the vertebrate control world.

So, there’s a point in the gimmick corner.

The problem as I see it here is that Barn Owls eat gophers.  We all know that-and if you don’t just go check out the base of an owl box in the spring.  You’ll find hundreds of gopher bones-along with other rodent parts-but gopher skulls, legs, ribs-heck you could probably build a gopher skeleton, something every wildlife control professional needs, out of what you find at the base of an owl roosting point or nest box.  So we know they do eat gophers.

The assertion in the article I read a couple months ago was basically what I like to call the “Field of Dreams Theory”.  If you build it, they will come.  So, if theoretically you had an area with a high population density of gophers or other pest rodents and you had barn owls in that part of the country (Barn Owls are in most parts of the country) then the more boxes you built-the more would get used because you are creating good nesting habitat-Barn Owls are cavity nesters-and there is an abundant food source with the aforementioned gopher population-so see, if you build it they will come!

Now we have our field of dream….uh, gophers, and we have a great gopher predator, and what will happen is the barn owls will thrive, to the point that they eat thousands of gophers per year.  So many gophers that there is no way that the hapless little rodents can keep up from a breeding standpoint and you’ve attained control.  Right?? Well, could be.

Let’s look at a couple things.  We know species adapt-so a percentage of these gophers are going to get wise to the “death from above” threat and adapt their habits to be less vulnerable.  We also know that predators will move away from an area that provides a decreasing prey base, due to competition from other predators, territorial disputes and so on.  So we have some changing variables here that are going to affect the outcome in our field.  I think this is the point at which the goal, effectively managing a rodent problem, gets lost sight of in the discussion.  If the owls have reduced the gophers to acceptable levels-then, we have a winner don’t we?  I’m not aware of anything, short of extinction, that controls a single pest species until the end of time, so for a moment in time, the owl nest box deal worked.  So, a point for the owls then.

Ultimately, there are a couple larger questions at work here.  The first is the predator/prey relationship.  So I ask you.  Does a large prey base control/attract the predator population, by supporting a high number of predators?  Or do predators control the prey population by keeping fluctuating numbers of prey at a steady predictable/declining level?

In my conversations with the gentleman in Pennsylvania he brought up his support for the reintroduction of wolves to the eastern seaboard in an effort to help control the white tailed deer population explosion that we all are so familiar with.  I couldn’t help but think of a gentleman by the name of Frank Glaser.  Frank was a government trapper and hunter from the mid 1920’s through the early 50’s in Alaska.  Frank was charged with tracking the migrating caribou populations and recording the effect of wolves on caribou and moose.

In his autobiography, Alaska’s Wolf Man, the Real Life Adventures of Frank Glaser (Jim Reardon) Glaser, who is refreshingly not in any way shape or form, politically correct (it was 1950 after all) blows away any notion that wolves only kill what they need and then only the sick, old or orphaned animals.  In fact, Glaser often shot them out of disgust or more correctly distain, after watching them kill caribou and moose strictly for sport-or for a display of territorial dominance.  Young caribou were routinely killed out of frustration, when the adults were too fast, and then left, untouched, by sulking wolves looking for an apparent “good or worthy kill”.

And the moose-they nearly wiped them out in parts of Alaska.  Wolves won’t take on moose in the summer or fall, they wait until the winter or early spring, when the prime adult males are exhausted from the rut and mating and can’t move around much in the deeper snow.  Then the wolves simply run them down, feed on their hindquarters while their still alive and then leave.  The moose dies in a couple days from the injuries, but the wolves won’t feed on a dead moose or even finish one off and feed on the hundreds of pounds of meat available-they just want a couple prime chunks out of the hindquarters, while it’s still warm…

So it would seem that our hope, that a predator, like a wolf or a barn owl, could be focused on a certain pest species is a little more hope and a little less biologically founded than we might be willing to admit.  Now, for perspective here, no one is worried about a declining gopher population due to “owl abuse”.  So the comparison kind of runs out of steam at this point, but I wasn’t the one who brought it up-the zoological expert from PA. made the comparison, so I’m just passing it along here for thought.

The next, much more difficult thing in my opinion to look at is the subjective nature of the term control.  What is control?  First of all, as wildlife damage professionals we all have an idea of what we think control is-but in most cases it’s the customers idea of control that matters the most.  Problem is few people spend as much time defining control as we do, so we’re all left with this interpretation variance to deal with.

I know in my experience with people with gopher problems, control is seeing dead gophers.  They (the customer) haven’t taken time to quantify the problem, they just see dirt mounds, or holes, or plant damage and want it to stop.  So if I install a Barn Owl nest box and they see owls-well then it must be working.  Notice I didn’t say anything about dead gophers.  If they see owls actually eating a gopher, I should be nominated for some sort of award.  If they see owls eating gophers and fewer mounds (cause I kicked them all down) and no more plant damage, I am some sort of animal control God.

Since I’m a God now, I’m filled with the wisdom and knowledge that I actually may have only started to scratch the surface of their problem.  Or that I could have used a rodenticide or traps and achieved the same results more quickly and consistently at a lower cost.  Or it could be that their problem was never really that large in the first place because I know that one pocket gopher makes several mounds and if you have 3-5 gophers in an area it looks like you have 100.

I guess the bottom line here is that Barn Owl boxes do work for gopher control, for some people, in some situations.  In other areas, it’s a feel good gimmick, because either the owls don’t exist in large enough numbers to offer any measure of control or the problem is simply to vast and varied for one type of control.  At the end of the day, that’s why you need a professional on site, to give you honest and informed feedback about what tools and options are available and how and why they should be used.

I guess the answer here is that before we label something either a sure thing, or a gimmick, we need to spend some time assessing the problem, the options and the goal.  Then we’ll know for sure whether or not what we’re getting ready to use is the best tool for the job. 

Barn Owls Live I saw this on the news this morning thought I would give you all the link to watch the Barn Owls live raising their young. http://www.ustream.tv/theowlbox

Tim Love with mole caught in EZ set

Loves Wildlife Control has hundreds of extremely happy customers. Many had never caught moles before but after buying a trap and taking instructions over the phone, are now catching moles at will. Call 641-891-7194 to order your trap TODAY!!!!

Published February 24th,2010 In the Iowa Farm Bureau Spokesman.

Operation Barn Owl Nest box
By Tim Love of Love’s Wildlife Control

Love’s Wildlife Control is proud to announce the involvement of Farm Bureau into the Operation Barn Owl Nest box project. Marion County Farm Bureau has graciously awarded a $500 community Enhancement Grant to LWC. The grant is good on a first come first served basis for $25 off a purchase of a Barn Owl Nest box or boxes for the first 20 Marion County members who get involved. The boxes are sold and installed by Love’s Wildlife Control. All sales and donations are put directly back into the project. Donations are greatly appreciated. Actual retail costs of these boxes are over $100 dollars each, but are currently being sold and installed by Love’s Wildlife Control locally for $70.

The Creation- My name is Tim Love, owner and operator of Love’s Wildlife Control (LWC). I resolve conflicts between humans and wildlife. I specialize in pocket gopher and mole control. Last spring (09’) while attending the Hawkeye Farm Show in Cedar Falls, a visitor to my booth told me that he used Barn Owls to keep his gophers in check in his hayfields. This conversation led me to begin research on the Barn Owl. I spent a great deal of time on the Internet and the telephone learning as much as I could about these amazing birds. I came to the conclusion that here in Iowa the barn owl has an abundance of prey available but few and dwindling numbers of nesting sites. I believe I am fortunate to operate a business doing what I love to do and feel compelled to give back to Mother Nature. I want to help the Barn Owl. Operation Barn Owl Nest box is a part of my business that I have set aside to operate at cost, to give back to nature.

The Plan- Give the Barn Owls a Home. Barn Owls are an endangered bird in Iowa. Barn Owls are very “wimpy” birds and have a high mortality rate but this high mortality is off-set by being highly prolific. 200 years ago, Iowa had large numbers of old hollow trees in which the barn owl could call home. In time, many of these trees were cleared by humans for development either for residential or agricultural use. As these trees were eliminated the Barn Owl adapted and took advantage of barns for protection, thus the name Barn Owl. Today many of the old barns have been remodeled with steel siding and access has been denied to the Barn Owl. The barns that have not been updated either are destroyed or left to ruin. This basically has left the Barn Owl homeless in Iowa. My plan is to erect as many nest boxes as I possibly can. This is the only logical thing we can do to help the Barn Owl. I believe that once these birds begin to find and use the boxes their natural abilities will bring their population back to acceptable levels in Iowa. This comeback will take years to happen and be slow in the beginning but once we have significant numbers of these birds reproducing, and continue to create homes for them, the population can thrive.

The Benefits- Having Barn Owls living on or near your property is very beneficial because these birds diet consists of nearly 100% rodents. A pair of Barn Owls feeding young, account for literally thousands of rodents consumed a year. The main rodent on their diet is the vole but mice, rats, moles, shrews, and gophers fit the bill as well. Rodents take refuge in terraces, waterways, fencerows and outbuildings. When larger predators such as the badger, fox, coyote, and skunk pursue these rodents in those places, considerable damage is done to your property. Rodenticide spread over the land is costly and unsafe to non targets, humans included. Control has different meanings to different people. I do not want to give the impression that Barn Owls will end all your rodent problems but that Barn Owls do provide a balance and make a considerable dent in the rodent population. Barn Owls in my opinion are a farmers best friend and employee as they work 24/7/365 consuming rodents.

Guarantee- There is no guarantee that you will get a Barn Owl to use the boxes. I can guarantee if there is no nest site available on your property you will not have them reproducing and thriving on your land. In my mind I see zero nest sites now. If we put two boxes in an area and 1 pair raises one brood of 5 young we are now short 4 boxes. You can clearly see the challenges that the Barn Owls face, all revved-up and nowhere to go! Since Barn Owls can have 2 broods a year you can understand why I think it is important to get as many boxes up as possible. Even one box in an area is a good start as more can be added later if a mated pair is known to exist.

Jessica Love after installing Nest box near Beech, IA.

To Date- Currently we have 26 boxes installed and 9 more boxes sold and ready to put up when the weather is fit. We can mount the uprights to an existing fence post but have found that it is best to mount the box on a 16’ 4X4 and set this in the ground. The boxes are made with ½” plywood sun shades built onto them. The box openings always face east to avoid the bad weather. The boxes are constructed of ¾” CDX plywood in such a way that water is shed off; they are screwed and glued together. They are stained gray with a very high quality stain made by “Super Deck” which features Carnauba oil. The upright posts are mounted to the bottom of the box with a steel bracket and are wrapped with a sheet of 24” aluminum flashing to keep climbing predators and unwanted guests out. This is the beginning of this project, so I do not know of any boxes being used but I have spotted 4 barn owls since last fall. Next fall (2010) Marla and I will be checking all the boxes for signs of use.

Pastures, next to row crops, provide plenty of rodents for Barn Owls.

Conclusion- Barn Owls need our help. Seeing a Barn Owl is like a religious experience to me and other bird lovers I have talked too. They are cavity dwellers and operate by cover of darkness so they are seldom seen. Many people I have talked with remember when they were young having a pair of Barn Owls in their barn. The main predators of Barn Owls are the Great Horned Owl and the raccoon. Since most hollow trees and old barns are currently occupied by the Raccoon, safe nest sites are very limited for the Barn Owl. Keeping these boxes out in the grasslands and away from the big woods offers the best protection from the Great Horned Owl and the aluminum flashing on the box post keeps the raccoon at bay. If you are a Marion County member and are interested in purchasing one or more boxes contact Farm Bureau at 641-842-6214. If you are not a Marion County FB member you may contact Love’s Wildlife Control at 641-891-7194.
Acknowledgements-The success of this project would not be possible without these people and I want to thank them for their help so far. First Lloyd Philips of Knoxville, IA has afforded me the use of his woodworking shop to build these boxes. Lloyd’s input of the box design and the hours that he volunteers towards this project, Bruce Ehresman of the IDNR for his past Barn Owl research and input into this project, Marla Mertz the Naturalist for Marion County Conservation Board, for here encouragement and very helpful presentation ideas, John Schuster of “Wild Wing Co.” of CA for his input of the boxes as well as information on the Birds, Paul Vitek of Spahn and Rose Lumber and Jeff Isley of Isley Welding and Repair both of Knoxville for the charitable contributions. Thank you all very much, Tim

Tim Love and Lloyd Phillips with the first box installed in Kay Harsin’s pasture.

For further information on the Barn Owl and the Operation Barn Owl Nest box project visit www.absolutegophercontrol.com and click on the Operation Barn Owl Nest box tab. Here you will find more in-depth details of the project and links to other sites about Barn Owls and information on how to order the video “Backyard Barn Owls” by Bert Kersey. This video is fantastic and worth every penny.

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POST RELEASE SURVIVAL AND MOVEMENTS OF CAPTIVELY
REARED COMMON BARN-OWLS IN IOWA

Bruce L. Ehresman, Douglas A. Reeves, and Kerry P. Schlarbaum

Iowa Department of Natural Resources
Wildlife Research Station
RR #1, Ledges Road
Boone IA 50036
ABSTRACT
From 1983 through 1987, 427 common barn-owls (Tyto alba pratincola) were captively reared and gently released in Iowa. Owls were released from 44 sites in 28 counties where grassland habitat appeared suitable. Numbers of verified barn-owl sightings reported to DNR personnel increased steadily during the project period from 17 in 1983 to 48 in 1986, probably due to greater public awareness about barn-owls brought on by information related to the releases. Numbers of confirmed or suspected nestings of barn-owls in Iowa varied from zero to 5 per year during the study period. No banded (released) individuals were known to contribute to any of the nestings. Thirty-six common barn-owls were equipped with radio transmitters and released during 1985 and 1986. Twenty-four perished before radio contact was lost, two were unmonitored because they escaped the radio harness, and 10 were known alive 30 or more days post-release. It does not appear that wild barn-owls have become significantly more numerous in Iowa because of releases of captively reared owls. Our emphasis now is on placing nest boxes in quality habitat areas where barn-owls are sighted, and increasing awareness of the barn-owl’s value through public education.
INTRODUCTION
The common barn-owl (Tyto alba pratincola) is a widespread resident of the United States. In southern and coastal portions of this country it is still considered common. However, in the Midwest and northern reaches of its range it has become increasingly rare during the last 30 years. In fact the barn-owl is listed as endangered or threatened in at least 7 Midwestern states. In Iowa, it has been listed as endangered since 1977 (14). This means the barn-owl is likely to disappear as a nesting species in the state if it declines further in numbers.
REASONS FOR DECLINE
Decline of the barn-owl can probably be attributed to a combination of factors. These include grassland destruction, loss of nesting and roosting sites, severe winter weather, predation, collision mortality, and possible pesticide effects (5,8,11,12,17). Marked changes in land use patterns have perhaps had particularly devastating effects in Iowa. Crop rotations which included about 25 percent meadow in the 1950’s are now replaced by two-year rotations of corn and soybeans throughout much of the state. As crop fields are enlarged, brushy fencerows, vacant buildings, woodlots and idle areas are eliminated which previously provided barn-owls nest and roost sites as well as foraging areas.
INITIATION OF RESTORATION PROJECT
An extensive literature review and discussions with raptor specialists provided initial support for the proposal of a project to enhance numbers of barn-owls in Iowa by releasing captively produced birds. Field inspections of habitat around known nest sites of native barn-owls, together with information on regional land use patterns further supported the notion that suitable unoccupied habitat existed in Iowa in at least the southern portion of the state. This information, together with the fact that barn-owls breed readily in captivity, gave Iowa Conservation Commission’s Nongame Wildlife personnel cause to begin a captive breeding and restoration program.
BARN-OWL PLACEMENT
Beginning in 1982, 93 barn-owls, both wild and captively produced, were acquired by the Iowa Conservation Commission (now the DNR or Department of Natural Resources) from rehabilitation centers and zoos in Washington, Oregon, California, Arizona, Texas, Louisiana, South Carolina, and Illinois. These were then used for captive breeding at the Boone Wildlife Research Station (WRS) facilities or placed at selected release sites. At the WRS rearing facility, adult owls were paired and placed in individual pens where they nested and reared their own young. More detailed information about housing, diet, etc. is recorded by Ehresman (8).
In order to place and release barn-owls, support and cooperation of landowners throughout Iowa was enlisted to assist with the project. The DNR publicly advertised a need for release sites, and the response was very good. Nearly 200 concerned citizens responded by offering their farmsteads as potential release sites. Landowners were sent a standardized form to complete and return so nongame staff could evaluate their sites. Foremost in the analysis was the amount of grassland in the form of hayfields, idle areas, wet meadows, and pastures that each potential release site contained. Other barn-owl studies indicate that suitable foraging habitat may be the most important factor for barn-owl reproduction (1,4). Also, b providing nest boxes in conjunction with foraging habitat, we hoped to document nesting of released owls. Many of the release sites chosen were later found to be in areas where barn-owls had previously existed.
Once release sites were chosen, the barns, silos, or out-buildings where the owls would be held were prepared. Olefin fiber netting was placed over openings to keep owls in and predators out, and a nest box was placed in the structure. To increase chances of documenting barn-owl nesting post-0release, other nest boxes were placed in the vicinity of the release site in nearby structures. Owl pairs from the Boone facility were usually placed at release sites during January and February. Release site attendants (usually landowners) then cared for the owls until they nested and reared offspring successfully. In many cases additional owlets of similar age from the Boone facility were added to these nests. Once the young owls were capable of sustained flight, the netting was removed from an opening in the building, and all owls (usually 7 or were allowed to come and go at will. All owls released were banded with US F&WS aluminum lock on bands. During 1985, 1986, and 1987, numbered colored plastic leg bands were attached as well. Colors used were red, blue, and yellow respectively. Release site attendants continued to feed the owls after release as long as the owls remained at the site (usually 2 to 4 days).
Besides placing barn-owl pairs at release sites, two other methods of placement were implemented. This included placing pairs from the Boone facility with their 3 to 4 week-old young. The final method involved placing groups of 5 to 7 barn-owls (usually fledglings) that were reared by captive pairs at the Boone facility or received as nestlings from other states. Normally owls placed by one of the latter methods were only held at release sites for 4 to 6 weeks prior to release. Release techniques for all 3 methods were the same.
From 1983 through 1987, 427 barn-owls were released from 44 sites in 28 Iowa counties (Table 1). Overall, 73 adult owls and 354 juveniles were released. Release areas chosen were primarily in the southern counties (Fig. 1), where most of Iowa’s remaining grassland exists. However, several release areas were chosen in northeast Iowa where most of Iowa’s dairy farming occurs, and in the Loess Hills of western Iowa, where there is some remnant native prairie.
After 2 years of releasing barn-owls. It was evident that the birds were not returning to release sites to nest. Aside from a limited number of sightings of barn-owls at or near release sites within 2 year post-release, there was no other evidence to suggest survival or nesting. To remedy this lack of information, barn-owl telemetry studies were implemented in 1985 and 1986 to gather knowledge about survival, movements, and habitat use of captively produced barn-owls released into the wild.
STUDY AREAS
Two different areas were selected for the telemetry studies. In 1985, two release sites were chosen near Chariton, Iowa, in Lucas County (Fig 2). The gently rolling topography in this southern Iowa location included a mixture of pasture, hayfields, idle grassland, row crops, and patchy timber. This area seemed favorable for barn-owl habitation, since barn-owls had been documented in the vicinity prior to owl releases.
The three release sites used in 1986 were further north than the 1985 release sites but still in the southern half of the state. Two sites were located east of Tama in southern Tama County, and the third site was located south of Chelsea in northern Poweshiek County (Fig. 2). The topography and habitat for two of the release sites was similar to those of 1985. The third site was located in the Otter Creek Marsh Wildlife Management Area (WMA). This site was selected because of predominant wet meadow and emergent wetland habitats which have been found in other barn-owl studies (2,4) to be important barn-owl foraging areas. It was also theorized that there would be fewer great horned owls (Bubo virginianus) in this bottomland habitat to prey on the barn-owls.
RADIOING BARN-OWLS
During January 1985, a pair of adult barn-owls was placed in each of 2 barns near Chariton, Iowa (Fig. 2). The owls were provided with a nest box and confined to the barn until they had mated, nested, and reared a brood to fledging. After the juvenile owls were flying well in the barn, backpack-mounted radio transmitters were attached to all of the owls using 1/8 inch diameter elastic shock cord. The transmitters were Telonics RB-5 models and weighed 27 grams. All birds were confined in the barn for 1 week after they were equipped with transmitters to assure that they could fly acceptably and had adjusted to the transmitters, a luxury that many wildlife telemetry studies do not have. One complicating factor was that the adults in the barn near Williamson (northern site) had already re-nested when the first brood was ready to be released. The first brood of young was released without accompanying adults. Later, the adults and the second brood were released. In all, 17 barn-owls were equipped with transmitters and released in 1985.
In 1986 a pair of adult owls was placed at each of 2 locations east of Tama. Each pair produced young, and the releases were handled in the same manner as the 1985 releases. In addition, 3 seven months-old and 2 two year old barn-owls produced at the Boone WRS were placed at a barn in the Otter Creek Marsh WMA, equipped with transmitters, and released. A total of 19 owls was equipped with transmitters and released during 1986. Smaller Telonics MOD-040* transmitter packages, weighing 18 grams, were used during the 1986 field study. They were attached using backpack mounts. In 1985, 5 radioed owls were released on June 26, 7 on July 3, and 5 on August 20. In 1986, 6 radioed owls were released August 19, 8 on August 27, and 5 on September 26.
 
RADIO-TRACKING BARN-OWLS
Equipment used to locate radioed owls included a car-mounted dual yagi antenna connected to a programmable Advanced Telemetry Systems* (ATS) receiver. Most locations were made with this vehicle-tracking system. Single element antennae were used when locating owls at close range (retrieving mortality victims or finding owls on roosts) and from aircraft when owls could not be located from the ground.
Owl locations were determined by triangulation using two or more signal readings taken from different locations. Whenever possible, right-angle comparison readings were made to specify the exact location. Compass bearings of each signal coordinate readings, as determined from the directional antenna readings, were recorded for each session and the points were plotted on a study area map. Locations were then recorded on a data sheet as Universal Transverse Mercator (UTM) coordinates to the nearest 100 meter grid (1 hectare). Using the vehicle-tracking system, radio transmitter signals had a range of 2 to 11 kilometers.
Radio locations of the owls were taken every night as often as possible during 1985, and daytime roosts were documented. In 1986, a main priority was to determine nightly activity patterns of individual owls, so some owls were monitored only every second or third day. As in 1985, locations were made mostly at night, and daytime roosts were noted. Efforts were made to determine the specific location of transmitters whose location had not changed appreciably after a 2 to 3 day period. Mortalities were noted and the probable cause of death was recorded.
BARN-OWL MOVEMENT
Barn-owls varied significantly in their response to release. At the Chariton release site most birds left eh barn during the first or second night. At one of the Tame release sites the birds stayed in or very close to the barn for 30 days. This created some difficulties with monitoring owl dispersal and survival, especially since the signal from some radios began to fade within 30 days, and most of the radios had ceased to function at the end of 45 days. The owls finally did disperse after food was no longer supplied for them in the barn, and they were forced to forage on their own. For most owls, once they had left the immediate release site, a pattern of movement did become apparent. After a short period (generally less than 4 days), they occupied identifiable home ranges that they then used for extended periods (up to 2 ½ months). Measuring to the geometric center of the home range, the mean distance travelled from a release site to a home range was 5.3 km for 7 birds that survived in excess of 30 days. During 1985, the 4 of 5 owls that lived more than 50 days following release then made extensive wide ranging movements during September. Unfortunately, because the smaller transmitters did not function as long during 1986, it could not be determined if the “surviving” owls made similar movements at the same number of days following release.
Several juvenile barn-owls travelled long distances during the study, and the direction of their movements following release appeared to be random (Fig. 3). In 1985, two birds travelled 48 km and 120 km northwest respectively; another flew 64 km northeast, and the fourth bird traveled 32 km in a southeasterly direction. In October 1986, 1 owl flew 40 km northeast before slipping its transmitter. Two owls that did make extensive movements were subsequently recovered. Both were killed in collisions with automobiles, one 48 km from the release site, the other 19 km from the release site after travelling to a distance of 64 km 2 months previously.
Random movements are not unusual for young barn-owls. Steward (17) termed these movements “post-natal wandering.” He noted that dispersal occurred in all directions during the first year out of the nest, and “of the 236 birds for which the places of recovery were determined, 63.7 percent were taken within 50 miles of the hatching places, and 34.3 percent were taken more than 50 miles distant.”
Band returns recorded for barn-owls (wild and captively reared) in Iowa from 1981-87 further support the fact that some barn-owls disperse to great distance (Fig. 4). The best evidence of this is a barn-owl banded as a nestling in southwest Iowa in 1981. In 1982 this owls was found dead 419 km away in extreme southeast Iowa were it had been the parent of 3 nestlings. All 7 owls that dispersed moved in an easterly direction 49 km to 419 km from where they were banded. This is inconsistent with Stewart’s (17) band return data which indicated more random directional movement.
MORTALITY
Twenty-four of 36 (67%) barn-owls perished before radio contact with them was lost. Stewart (17) found that 65.2% of first year birds do not survive. Two of the 36 radioed owls were not monitored because they slipped out of the transmitter harness within 2 days after release. “Surviving” owls are defined as birds that were still alive when radio contact was lost at least 30 days following release. Ten of 36 (28%) fit this category. Causes of mortality were assigned as follows:
1. Avian predation was attributed to barn-owl remains where either:
a. An avian predator was flushed from the carcass;
b. The remains were scattered over an area directly beneath a tree, and whitewash was found at the site, or;
c. The remains were picked clean, and bones and feathers were not chewed.
2. Probable mammalian predation was indicated when remains were found accompanied by scats of mammals, or when bones and feathers had been chewed; the owl had been dead too long to determine the cause of death.
3. Auto collision mortalities were found near roadways, and subsequent investigation indicated that severe trauma attributed to a collision resulted in the death of the bird.
4. Unknown deaths were those which could not reliably be assigned an obvious cause.
Great horned owls preyed on barn-owls. Several other authors have noted this (2,4,11,19), but not as frequently as we experienced. At least 9 of 24 37.5%) barn-owl deaths were attributed to great horned owl predation, and 4 other avian caused deaths may have been great horned owl casualties. Overall, 13 of 24 (54.2%) barn-owl deaths were caused by avian predation. Great horned owls were flushed from barn-owl carcasses, and it appeared that at one release site, the great horned owls became accustomed to catching and killing barn-owls., since they caught at least 4 of the birds within .5 km of the release site. All 4 were fledglings from the second brood radioed at a release site. Two owls were killed by great horned owls after the first release at this site also. It is known that great horned owls kill “wild” barn-owls in Iowa too. In 1985, a fledgling barn-owl was consumed by a great horned owl after it left its barn cupola nest in Clarke County (Beth Brown, pers. comm.). In an owl pellet study done in eastern Washington, it was found that “common barn-owls are the fourth most important prey item, in terms of total prey biomass, in the diet of great horned owls” (11). If fledgling barn-owls are in fact a normal item in the diet of great horned owls, there may be little chance of barn-owls becoming abundant where great horned owls occur in Iowa.
Although the extent of predation by great horned owls was greater than expected, it was not surprising to find that auto collisions accounted for 4 of 24 (16.7%) radioed barn-owl deaths. Past records of barn-owl deaths in Iowa (8), indicate that vehicle collisions do take their toll on barn-owls. Other studies have documented barn-owl collision mortality as well (10,15,16). In California, Schulz (15) indicated collisions with vehicles may be the major mortality factor in that state. During the telemetry study, numerous barn-owls were documented spending time along grassy roadside ditches. These areas are probably preferred hunting areas because adjacent fence posts supply low perches from which to hunt, and the ditches harbor an abundance of rodent prey. At least twice during the field studies a barn-owl was seen flying low across a roadway and was barely missed by a moving vehicle.
Two of 24 (8.3%) barn-owl mortalities were probably mammalian predation victims, and 5 (20.8%) owls were found dead of unknown causes (Table 2). Mammalian predation occasionally is documented on wild barn-owls (2). Of the 5 owls found dead of unknown causes, it is probably that 2 dies of starvation at the release sites.
Mortality was greatest during the first 20 days post-release. Chi-square analysis indicated that this was statistically significant (P < .01) for the two years pooled as well as for both individual years. Upon further investigation it was discovered that, with one exception, all know avian predation occurred during the first 20 days following release. Mortality after 20 days was attributed to probable mammalian predation, unknown causes, or auto collisions. This was interpreted to indicate a learned avoidance response to major predators (particularly) great horned owls) following an initial encounter.
Because of differences in the behavior of owls during the 2 years, and because of differences in the longevity of radio transmitters, it is difficult to make direct comparisons of the mortality information for the two years. One reason the mortality patterns appear different for the two years could be the differences in the weight of the radio transmitters. It is known that transmitter weight can affect avian survival (7.18). However, 5 birds wearing the heavier transmitters did survive for at least 55 days, and this same radio package was used by Ault (1) in a study of wild barn-owls in Oklahoma without negative impact. In Ault’s study, the radioed owls were carrying cotton rats (Sigmodon hispidus) (2nd most important food item) to the nests with no apparent transmitter-related problems. Cotton rats’ weight usually averages 115 grams (3), which was about 25 percent of the weight of many of the owls.
Another different in survival between years can be explained by the fact that 5 of 6 owls at one 1986 release site essentially stayed in the barn or close proximity to it for 30 days following “release,” and as a result were not subjected to the same mortality factors that the other owls were during the same time interval. In fact, 2 of the owls were never located more than 1 km from the barn before radio contact was lost. Barn-owls released at other sites usually moved away from the site within 1 week. Another factor that undoubtedly explains some of the apparent difference in mortality patterns between the 2 years is the longevity of the radio transmitters. Complete information was recorded for the owls during 1985 to beyond 40 days. During 1986, contact was lost with 4 owls during the 21-40 day interval. If those birds could have been followed for a longer period, a different mortality pattern might have been indicated.
Barn-owl mortality causes have also been documented from the 1983-87 barn-owls released in the form of band returns. To date, only 16 of 427 (3.8%) barn-owls released have yielded band returns. Of these 16, 5 died of apparent starvation, 4 were vehicle collision victims, 4 died of unknown causes, and 3 died of “other” causes. Three of the five owls which apparently starved did so because of severe weather conditions. One owl was found dead after it had been raining for 10 of 14 days, and the owl may have been unable to hunt effectively during that period. Two owls were found dead in Wisconsin in January following severe cold coupled with deep snow. Starvation of barn-owls during winter is not uncommon since many barn-owls do not migrate south (8,9,13). Of the 3 owls which died of “other” causes; 1 was bitten by a dog, 1 was killed when a grain auger was activated (the bird was roosting inside), and the third owl died of apparent heat exposure after being chased by other barn-owls in a building during hot weather.
BARN-OWL SIGHTINGS
Although the mortality documented by the telemetry studies paints a grim picture for survival of captively reared barn-owls in Iowa, there is evidence to indicate that barn-owls continue to exist here. Prior to 1983, it was unusual to document more than 4 barn-owl sightings in a year, and from 1950-1979, Dinsmore, et al (6) recorded only 7 nests. During the 5 years of barn-owl releases, 1983-87, a total of 171 barn-owl sightings were verified, 7 barn-owl nests were confirmed, and 7 possible or probable nestings were reported.
We hoped that by placing colored leg bands on released owls, the owls would be more visible and more sightings would result. However, there have been only 3 subsequent sightings of banded birds. These owls were observed alive at distances of 4.0, 5.6, and 11.3 km from the nearest release sites for 3-8 months following release.
Of the 171 verified sightings, (Fig. 5), 80 (46.8%) were of owls seen within 12.8 km of release sites, and 9 of those 80 were owls seen at release sites. One of the 9 owls seen at a release site was known to be a wild owl. The other 8 may have been captively reared birds.
Even though there have not been documented nestings of banded barn-owls, it is probable that some released owls do return to their natal site. Stewart (17) documented 65.7 percent of barn-owls banded at hatching sites were later found within 50 miles of these places. Because of these findings he felt “it is reasonably certain that some birds remain to nest in the general locality of their hatching places.” Bruce Colvin (unpublished) has documented in a New Jersey study area that among 49 adult birds handled in 1987, 5 (10.2%) of those were banded as chicks in the study area. And those 5 were among 870 young banded from 1980-86. Colvin’s 1986 data (unpublished) indicated 16.9 percent of the adult population were banded as nestlings on the study area.
Another factor that may have influenced the large number of reported barn-owl sightings near release sites could be increased public awareness that the DNR was interested in these sightings. Most releases involved newspaper coverage, and in some cases, television coverage. This resulted in a better informed public, particularly in release site areas, who were probably more likely to report barn-owl sightings than in areas where publicity did not occur.
 
BARN-OWL NESTING
Seven barn-owl nests were verified during the study period. Five of them were documented in 4 southern Iowa counties (Fig. 6), and the other 2 were at the same site in northwest Iowa (Sac County) for 2 consecutive years. Five adults were observed well enough at 3 sites to determine they were unbanded; no banded adults were sighted at active nest sites. Even though no banded birds have been seen at nest sites, one of the last locations made on a surviving radioed barn-owl in 1985 was just across the road from a site were barn-owls nested successfully in 1986.
CONCLUSION
Captive bred barn-owls have been documented nesting at release sites in Missouri and Nebraska. The release of over 200 barn-owls in a localized area of Missouri did result in at least 2 active nests involving released birds the following year (Walter Crawford, pers. Comm..). Nebraska Nongame Biologist, John Dinan (pers. Comm..) reported from 1 to 5 pairs of barn-owls nested at or near release sites following the release of over 150 barn-owls in a southeastern Nebraska area. It was unknown if any of the nesting owls in Nebraska were release birds, however.
There have been over 1,000 captive-reared barn-owls released in Iowa, Missouri, and Nebraska in the last 6 years (Crawford, Dinan, pers. comm.). Even with this large number of owls introduced into the wild, there is still not much evidence that these releases have had a significant positive biological impact on the Midwest barn-owl population.
The positive impact that has resulted from the releases (at least in Iowa) has been an increased public awareness of barn-owls. Educating the public about barn-owls is an important part of the Iowa DNR barn-owl restoration program. More people are now reporting barn-owl sightings, because they realize they are seeing something special. The Iowa DNR will no longer be releasing captive-bred barn-owls. Public education emphasis will continue, as will the placement of barn-owl nest boxes in areas where barn-owls are known to occur.
We do not feel that the captive-release program has been a failure. We have learned much about Iowa barn-owls which will be channeled into management of barn-owls to ensure their future in Iowa and the Midwest.
ACKNOWLEDGEMENTS
A special thanks is extended to all the folks who helped with this project. Without the hundreds of hours of volunteer time put in by these cooperators, the success of the restoration effort would not be realized. Thanks also to Rita Knight and Sandy Monen for typing this manuscript and to Mariene Ehresman for her editing efforts.
 

REFERENCES
1. Ault, J. W. III. A quantitative estimate of barn owl nesting habitat quality. M.S. Thesis, Oklahoma State University. 1982.
2. Bunn, D. S., A. B. Warburton and R. D. S. Wilson. The barn owl. Buteo Books, Vermillion, S.D. 264 pp. 1982.
3. Byrd, C. L. The home range, habitat, and prey utilization of barn owl (Tyto alba) in south Texas. M.S. Thesis. Texas A&I University, Kingsville. 88 pp. 1982.
4. Colvin, B. A. Barn owl foraging behavior and secondary poisoning hazard from rodenticide use on farms. Docotoral Diss. Bowling Green State Univ., OH. 326 pp. 1984.
5. ________. Common barn-owl population decline in Ohio and the relationship to agricultural trends. J. Field Ornithol. 56:224-235. 1985
6. Dinsmore, J. J. et al. Iowa birds, Iowa state University Press. Ames, Iowa. 356 pp. 1984.
7. Dunstan, T. C. A harness for radio-tagging raptorial birds. Inl. Bird-Banding News 44 (1): 4-8. 1972 in Schemnitz, S.D. Wildlife management techniques manual, 4th ed. The Wildlife Society, Washington, D.C. 686 pp. 1980.
8. Ehresman, B. L. Common barn-owl restoration in Iowa. Wildlife Rehabilitation. Pro. Nat. Wild. Rehab. Symp. Vol. 3:10-19. 1984.
9. Errington, P. L. Winter killing of barn owls in Wisconsin. Wilson Bull. 43:60. 1931.
10. Glue, D. E. Ringing recovery circumstances of small birds of prey. Bird Study 18:137-146. 1971. In Bunn et al. The barn owl. Buteo Books, Vermillion, S.D. 264 pp. 1982.
11. Knight, R. L. and R. E. Jackson. Food-niche relationships between great horned owls and common barn-owls in eastern Washington. Auk 101:175-179. 1984.
12. Lavcock, G. Dark days for barn-owls. Audubon 87:28-31. 1985.
13. Marti, C. D. and P. W. Wagner. Winter mortality in common barn owls and its effect on population density and reproduction. Condor 87:111-115. 1985.
14. Roosa, D. M. 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. 4:12-25. 1977.
15. Schulz, T. A. Conservation and rehabilitation of the Common barn owl. Wildlife Rehabilitation. Proc. Nat. Wild. Rehab. Symp. Vol. 5:146-166. 1986.
16. Smith, D. G. and C. D. Marti. Distributional status and ecology of barn owls in Utah. Raptor Research 10(2):33-44. 1976.
17. Stewart, P. A. Dispersal, breeding, behavior and longevity of banded barn owls in North America. Auk 69:227-245. 1952.
18. Warner, R. E. and S. L. Etter. Reproduction and survival of radio-marked hen ring-necked pheasants in Illinois.J. Wildl. Manage. 47(2):369-375. 1983.
19. Wayne, A. T. A death trap to the American barn owl (Tyto pratincola). Auk 41(2):342. 1924.

TABLE 1. CAPTIVE-REARED BARN-OWLS
RELEASED 1983-1987
Year Adult Young Total

1983 12 46 58

1984 19 69 88

1985 17 82 99

1986 19 110 129

1987 6 47 53

Total 73 354 427

TABLE 2. CAUSES OF MORTALITY IN RADIOED
CAPTIVE-REARED BARN-OWLS
1985 1985 1986 1986 1985-86 1985-86
Cause

Avian
predation 9 64.3 4 40 13 54.2

Probable mammalian
predation 0 0 2 20 2 8.3

Auto collision 3 21.4 1 10 4 16.7

Unknown 2 14.3 3 30 5 20.8

Totals 14 100 10 100 24 100

Figure 1: Number of captive-reared barn-owls released in each of 28 counties were 427, released at 44 release sites from 1983-87’.

Figure 2: Barn-owl telemetry release sites.

Figure 3: Radioed, captive-reared barn-owl movements during 1985 and 1986 at least 30 days post-release.

Figure 4: Barn-owl movement from band returns from 1982-1987.

Figure 5: Number of verified barn-owl sightings in 50 of 99 counties where 171 were seen from 1983-1987.

Figure 6: 7 confirmed barn-owl nests in 5 counties from 1983-1987.

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.

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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