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Creating a Wild Backyard: Barn Owls

The barn owl is one of the most celebrated species in literature, especially in folk tales. Its habit of nesting in the belfries of churches and hunting at night over graveyards has made the barn owl somewhat of a superstitious legend in Europe.

Their ghostly appearance, with a golden-tan back and white underside, and their vocal series of shrieks, snarls, and hisses add to the birds' mystique. Local names for the barn owl include the "ghost owl" and the "monkey-faced owl" - named because of its expressive, heart-shaped face and dark eyes.

Natural History

Barn owls are found throughout Maryland, especially in rural areas where there are grasslands, marshes, hayfields, or abandoned fields. Farmers consider themselves fortunate to have barn owls on their farms to help control the mice and other rodent pests that damage and eat grain and other farm produce. Barn owls nest within easy reach of the fields where they find their favorite food - meadow voles. Nest sites include abandoned buildings, barns, silos, hollow trees, rock walls, and holes in banks and cliffs. Barn owls lay 4-10 eggs directly on the floor of the nest site they have chosen. The eggs, incubated by the female, hatch in about 30 days. The male takes on his role after the chicks are hatched and brings food to them. About 10 weeks later, the chicks are ready to fly. Barn owls can nest all year long, but usually do so between March and September.

Barn Owl Nest Box on Maryland Marsh

Barn Owls on the Decline
All over the world, where barn owls normally live, their populations are declining. In Maryland, biologists are working to determine why this is so and how we can increase barn owl populations.

One of the reasons that there may be fewer barn owls than in days gone by is that there are fewer places for the birds to nest and raise their young. Barn owl boxes, placed in the right setting, can help increase the numbers of barn owls in your area. There are two types of barn owl boxes: the wall-mounted and tray nest boxes.

How to Build a Wall-Mounted or Free-Standing Nest Box

Materials:

1" x 16" x 16' untreated lumber
1 1/2" nails
Non-corrosive hinged cabinet lock
2 strong, non-corrosive door hinges

Construction:

1. Mark and cut the pieces out of the lumber.

2. On the front piece, make a square entrance hole 6" x 6". Make a corresponding hole in the wall of the barn or silo. The entrance hole should be 7" from the bottom of the box.

3. Use nails to assemble the box: front, bottom, back and sides. Use the hinges to attach the top to the box.

4. Use the cabinet lock with a padlock through the loop to close the top down onto the box. This will allow you to open the box when cleaning it and keeping it closed while the birds are nesting, so that they will be protected from predators.

5. Drill several drainage holes in the bottom of the box.

6. Drill small holes in the tops of the sides for ventilation.

7. Place the box on an interior crossbeam flush with a barn wall or directly on the wall itself.

8. If in a barn, secure near the wall where you have cut a 6" x 6" hole.

Cutting & Assembly Illustrations
For Wall-Mounted or Free-Standing Nest Box

How to Build a Tray Nest Box

Materials:

1" x 12" x 9' untreated lumber
1" x 15" x 36" sheet of untreated lumber
1 1/2" nails

Construction:

1. Mark and cut the pieces out of the lumber.

2. Assemble as shown.

3. Drill several drainage holes in the bottom of the tray.

4. Secure the tray near he upper rungs of a silo ladder or on the silo wall. Note: the silo must have a closed top. Barn owls will not use a tray in an open-topped silo.

Tips for Attracting Barn Owls

• Barn owls are not usually urban or suburban birds, mainly because there are few large open fields in these areas. You have a chance of attracting barn owls if you live in a rural area with grass, hay, or abandoned fields nearby or with wet meadows or salt marsh.

• If you have a seldom used or abandoned barn or silo, check for the presence of barn owls by looking for two inch black pellets on the ground inside the building. These are pieces of indigestible fur and bones from the animals eaten by the owls. If you see these you very well may have a resident barn owl that might nest in a barn owl box. Try to place your box near the area where the pellets were found.

• Place your barn owl box 20 to 25 feet off the ground in a covered barn or silo that is not often used.
  

• Clean your owl nest box once a year. Usually, January is the safest month to do this, but barn owls can be nesting at anytime during the year. Pigeons may try to nest in the box so be sure to remove them and their litter, as well as any pellets or other prey remains.

• Do not disturb the owls while they are nesting. Adult owls will sometimes abandon their eggs if disturbed. Be observant of any occupation of your nest box before disturbing it.

• Face a wall-mounted box away from prevailing winds.