Lake & Wetland Management employee, Bill Shea, constructed a Barn Owl nest box and we installed the fruits of his labors in the Lake & Wetland Management Boynton Beach nursery this morning. Bill used scrap plywood and an old length of metal pipe that had been left over from other projects at the nursery to construct the box. We’d seen Barn Owls elsewhere in the Palm Beach County Agricultural Reserve, even as recently as this past Sunday, so we placed the box in a relatively quiet corner of the nursery in the hopes of attracting Barn Owls to bolster the local population for conservation efforts and for low cost, all-natural, environmentally-friendly rodent control.
What Is the Habitat for a Barn Owl?
One of the most widely distributed birds in the world, Barn Owls can be found on all continents with the exception of Antarctica. They are well-suited to a variety of habitats and altitudes, including:
- Agriculture Fields
- Urban Areas
- And of course, Barns
Barn Owls like to nest in open areas, which is why you will see their nest in buildings, hollow trees, and nesting boxes. Like most raptors, Barn Owls are monogamous, and pairs will stay together for several breeding seasons. In Florida, these beautiful birds usually lay their eggs in February. In South Florida, they will often lay a second set of eggs in the late summer or early fall.
Each clutch of eggs ranges from four to six eggs on average. An owl lays her eggs about 2-3 days apart, and they hatch in that order, giving each chick an age difference of a few days. This survival mechanism ensures that some chicks will survive in seasons when food is scarce.
Where to Install an Owl Barn Box
Barn Owls are nearly cosmopolitan in distribution, being found on every continent except Antarctica. They favor grasslands, agricultural areas, and other open habitats punctuated by caves, hollow trees, barns, church steeples and other structures where they can bring up their sizable families.
Purpose of the Barn Owl Box
Another requirement is a steady supply of small rodents and other prey. A Barn Owl can consume up to six rodents in the course of a night’s hunting so, for obvious reasons, they are exceptionally popular with farmers. Hundreds of similar Barn Owl boxes are employed elsewhere in south Florida agricultural areas, especially in sugar cane operations. With any luck, our box will hopefully attract an owl family in the coming months.
Benefits of Using a Barn Owl Box
Barn Owls are great for rodent control, and many Florida orange groves and Florida counties use them for this purpose. We installed ours for just that purpose. The main factor limiting Barn Owls in Florida is the lack of suitable nesting sites. Nest boxes are generally occupied quickly and at close to 100% occupancy. This makes it easy to establish a Barn Owl population for rodent control.
How to Build Your Own Barn Owl Box
As their name implies, Barn Owls like to nest in man-made structures such as silos, sheds, barns, and church steeples. Their nests are very messy places, strewn with remains of the prey they’ve eaten and their excrement pellets. By building and installing a nesting box, you can create a place for Barn Owls on your property and avoid dealing with their mess in your buildings.
You’ll notice that we used scrap plywood and an old metal pipe to create our barn owl nesting box. You can use scrap wood and metal, if you have it, or use the materials listed below. It is important to make the nesting box big enough and install it in an area the Barn Owls will enjoy.
Here’s what you need:
- One 4 feet x 4 feet sheet of 5/8 inch exterior plywood
- One 1 inch x 12-inch pine board, 6 feet long
- One 4 inch x 4-inch pressure-treated post, 16 feet long
- One box of #6 1-5/8 inch galvanized screws
Directions for Construction
First, cut the top, front, and back of the nesting box from your sheet of plywood:
- For the top: one 38 inch x 12-1/2 inch piece
- For the front and back: two 38 inch x 17-1/2 inch pieces
- For the front panel, cut a 5-inch wide x 51/2 inch high entrance hole that is approximately 2″ away from the left-hand side of the panel and about 7″ from the bottom.
Cut the bottom and side panels from the piece of pine board:
- One 11-1/4 inch x 38-inch piece (bottom)
- Two 11-1/4 inch x 16-3/4 inch pieces (sides)
Drill at least ten drainage holes in the bottom piece.
Arrange and screw all plywood and pine-board pieces to form a box. The dimensions should be 38-inch width, 18-inch height, and 12-1/2 inch depth.
Attach the box to the post and install it at the edge of an open area or field. You want the owls to be able to glide freely in and out of the nesting box. Face the box north, to keep out the sunlight. You can also mount the nesting box, minus the post, on barn walls, shed rafters, or in silos if you prefer.
The Barn Owls nest on top of the feathers, prey debris, and pellets, this helps insulate the eggs as they incubate. If the nesting box gets too full, the owls push it out, so you don’t need to worry about cleaning out the boxes.
Barn Owl Nest Box Tips
If you want to build and install a Barn Owl nesting box, here are a few tips for constructing a box that is safe and attractive to owls.
1) Make sure the box is big enough. Barn Owls can produce a lot of chicks, and the entire brood must grow to adult size within the nest box. Fewer birds will survive if your nest box is too small.
2) Make sure the entrance is small enough. The entrance hole should be just big enough for the owls to squeeze through, but not big enough for predators to get inside.
3) Make sure the location of the entrance is high enough. If the entrance is too low, the chicks may fall out as they crowd around the hole.
4) Make sure it is the right color. These boxes get extremely hot, so make sure to paint yours bright white to keep heat absorption to a minimum. Plan to repaint every few years.
5) Make sure you use the right materials. If the plywood you use is too thin, it will rapidly deteriorate in the elements and you may have to replace it sooner.