Where to Place An Owl Box

Location is the most significant component for habitation success when considering where to place an owl box. It is difficult to predict with certainty whether a box will attract owls, and the best locations are sometimes determined by trial and error. However, there are fundamental guidelines that can help attract barn owls. Furthermore, once owl boxes are occupied, more can be added.

Barn Owls do not necessarily hunt in close proximity to their nest. Therefore, nest boxes can be placed some distance away from heavily infested areas and strategically placed in overlapping areas. Regardless, placing a perch in an area of high rodent infestation will encourage the owls to hunt in that area. Placing the boxes one hundred yards apart is quite adequate. This should provide sufficient coverage and allow for some territorial behavior by the male. Barn owls are also known to leverage water sources, ponds or streams with pools can be found useful by the owls.

Boxes may be located near tree lines – 100 yards - to provide a nearby perch for young as they venture out of the nest. However, the box should not be too close to dense woods which, in Northern California, are the habitat of the Great Horned Owl and the Red-Tailed Hawk, the Barn Owl’s primary predators. If you have trees on the perimeter of your vineyards, install post boxes on the outside of the foliage drip line.

In vineyards, it is best to place boxes between rows at the end of a row of vines, not in the center of vineyards or at the end of vineyard rows. Place boxes on vineyard lanes taking care that there is open space in a five-foot radius around the post providing the owl with visibility to the immediate hunting ground and for easy access for maintenance.

In vineyards with proximal trees, rodents are often in the uncultivated area between the trees and cultivated crops, and the number of owls that can be supported is determined by that area.

Because the flight path of owls is low, large trucks and trains are the number one killer of Barn Owls, box placement should not be near roads or train tracks that have significant night-time traffic.

Second, do not place boxes on or near utility poles. Barn Owls, along with many other raptors and different species of birds, commonly die from interactions with power lines.

Third, boxes should not be placed close to vehicles and equipment as pellets are highly corrosive to metals.

The question isn’t: Will Barn Owl boxes reduce my rodent problem? It’s really: How many boxes are required to do the job?” While the food supply remains dependable, the owls will return season after season. Extra boxes will allow for the natural fluctuation of both prey and Barn Owls. Barn Owl densities of one pair per acre in non-irrigated fields would be necessary to remove the annual reproductive output of gophers.

It’s recommended that when spacing the boxes around the rodent-infested areas, about four to six will handle 50 light to medium infested acres. Where rodents are not such a serious problem, the same number of boxes will work for 100 acres.

The biggest mistake a grower can make is to not providing enough sites. Those who have multiple nest boxes in place, find that 40 to 70 percent of them are used by the birds, so installing just one box may or may not work. Keeping in mind the success rate of box habitation is about fifty percent, put up two, three, or more boxes to increase your chances of attracting some. From then on, add one or more boxes each year to keep ahead of the population. When 70% of your boxes are populated, you have attracted all the owls your land will support.

The Amador Barn Owl Box is suitable for mounting in trees or structures although pole mounting is becoming the most common. Nest boxes can be attached to a tree, a building such as a barn, or a post away from intense human activity. They should face into an open area away from prevailing winds.

Traditionally, Barn Owls have made their nests in trees or buildings although any structure with a hole will do. However, as trees have given way to cleared land, the pole mount has become more popular.. If trees are selected, note that a clear approach path to the box is needed and, as with any mount, the box must be level to the ground.

As noted earlier, mounting the box on a barn or other building is a possibility, but there is evidence that given a choice owls prefer the sites with the least human activity.

Please see: "Installation Instructions" page

We’ve seen success with no filler, as well as dry natural materials as a floor liner.

Fundamentally, there is no need to put any nest material inside the box. The owls will regurgitate pellets, consisting of undigested bones and fur into the box and the female will create a soft nest for the young by carefully breaking the pellets apart.

However, early on, because owls bring in no nest material, you might add a ¾” layer of wood shavings or dry grasses.

Again, we’ve seen success with both no filler and filler.

A barn owl family will create three inches or more of debris in the box in one season. The box should be cleaned out using a trowel or other cleaning tool once a year during August or September.

NOTE: Cleaning the box can cause exposure to Hantavirus (Hantavirus Pulmonary Syndrome). For protection, rubber gloves and a good dust mask should be used during the process, and every effort should be made to avoid exposure to the dust.

During the cleaning, the box should be inspected for damage, and appropriate repairs are done. A few drops of oil applied to the hinges will prolong their serviceable life. After cleaning, add a layer of fresh wood chips about ¾“ deep to the box.

If an owl is in the box when it is opened, close the box, and try another day.

If a box is occupied a white ring will often appear around the entry hole and scratch marks from the owls exiting and re-entering the box may be visible. Other possible signs of use are pellet debris hanging from the drainage holes and whitewash on and around the box. The sound of hissing is an indication that young owls are in the box—they will vocalize in this manner if they are disturbed. The presence of adult owls in the area around the box may also indicate that the box is inhabited. The adult owls can be heard shrieking over the fields after the sun has gone down and metallic clicking sounds can occasionally be heard when they fly in the vicinity of their nest. Occasionally there will be no signs of occupancy, but the box will indeed be in use.

In Northern and Central California, Barn Owls begin selecting nesting sites in December or January in time for the February to May nesting season. Occasionally new nests may be started as late as March but that’s getting late as peak hatches are in April. By July, most nest boxes have been vacated by the young who have flown to nearby trees or buildings for the final stages of their development. It is best to install the new Barn Owl Box before January, February at the latest.

Please contact us with any questions on this material: info@amadorbarnowlbox.com