Box Eight Down!

It's been a long summer here in the Piedmont, and to our knowledge, we have yet to attract any owls to our nest boxes. That's OK, because odds are long for getting owls the first season. We knew this would be a long term process.

We suffered a minor setback when box number 8, at Anilorac Farm, went down. I drove by one day and the box appeared to be missing!! After a little investigation, it turned out that the box and pole had merely been knocked over.

The owner of Anilorac suspects the box may have been blown over by a strong wind. When I inspected the site, however, it looked like someone may have lowered the pole and box to the ground. There was no damage to the box.

Local farmers lease the land, so it's possible the box was lowered for some reason unbeknownst to us. In any case, we will re-examine our pole mount system to see if we can't improve on it in cases of wind. We may have to use guy wires to secure boxes located in vulnerable areas. 

When I returned the box to the upright position, I tested the wobble of the tire and pole, and the system seemed pretty secure. The box itself looked a bit pitiful in its dirty state, but the molded plastic has proven itself to be a resilient material.

Boxes 9-12 should be up soon, so stay tuned.

Creating Our Pole Mount System

Barn Owl nest boxes need to be ten feet or more off the ground. When installing a box in an open field, this fact can present some logistical problems. Most poles at the hardware store are exactly ten feet long, or at longer lengths that require costly cutting. Poles placed in the ground need a hole of two feet or more, making a ten foot pole potentially unviable. Installing poles on site could take a couple of hours or more.
One of our volunteer carpenters, Robin, suggested using 1 1/2 inch diameter gas pipe mounted in a concrete-filled tire as a nest box support. A standard ten foot section of pipe from Lowes would then stand exactly ten feet tall. We decided to try that system at Mason Farm, and it worked perfectly. The piping was solid, and there was little sway due to the weight of the concrete.  So we decided that we would use this system for all 25 of our nest boxes.
One downside to using this system is that it takes time to set ten feet of pipe in concrete. The pipe-in-tire setup is also extremely heavy, and must be maneuvered carefully for transport. There are also unforseen consequences of using old tires. Worn steel belted radials, for instance, have a tendency to slice a finger open if given the opportunity (a fact that I learned first hand).
The upsides to using this setup, though, far outweigh the downsides. The tire setup is mobile, allowing nest boxes to be moved when necessary, as for a prescribed burn. The system can also be assembled at a neutral site, which means a faster installation once in the field. The boxes can be brought down easily for cleaning. And in the case of a hurricane, which is not an uncommon event in this part of the country, the boxes can be brought down entirely to escape the wind.
On our first two "pole workdays," we set aside two to three hours, with two to four volunteers present. Per Robin's original instructions, we first lay a piece of plywood on flat ground. We then lay one or two tires down, with tar paper placed at the bottom of the holes to prevent wet concrete from leaking out. We then hammered short lengths of 2X4 into the ground around the tires.

Next we used wood screws to place buttresses at an angle, to help stabilize the pipe. Two buttresses per tire allows a pole or pipe to be fully supported at a right angle. 

A 1 1/2 inch diameter pipe was then secured to the buttresses using clamps. Pipe can be very heavy and cumbersome, but is very solid once fixed in place. One inch pipe is also OK to use, but be sure to get the proper sized flange for attachment to the nest box.

Next we mixed the concrete: two 80lb bags per tire. That seemed like a lot of concrete, but the weight of the tire is what gives the pole its stability.

Packing the concrete into the tire is fairly rewarding. Once filled, the concrete is evened out and smoothed. 

We managed to finish two poles this weekend in two hours, with four people. With some practice, we should be able to finish in half the time. If you have some carpentery or handyman skills, and would like to help us mix concrete and set the poles, please let us know.

After 24 hours, the mounts are be ready to go. We will be using these poles to install boxes 5 and 6 this weekend!!

Our Nest Boxes

As chair of the New Hope Audubon conservation committee, I set out to find the most suitable nest box for our Barn Owl Initiative. After several weeks of research, I came upon the work of Mark Browning, a researcher and animal trainer for the Pittsburgh Zoo. Not only had Mark designed the perfect nest box for our purposes, he had years of experience with Barn Owl restoration projects.

Mark Browning studied Barn Owls for many years in his home state of Pennsylvania, and was unimpressed with traditional designs for nest boxes. The boxes were typically made of wood, and were subject to rot. They were often not deep enough to prevent predation. A hungry Great Horned Owl, the top predator of Barn Owls, could snatch an owlet from a box that wasn't properly made. What Mark came up with is the plastic molded box pictured below:

A molded plastic box has many advantages. Because it is lightweight, it can easily be installed on a small diameter pole. It is also more durable, able to withstand many years of punishment from the wind, rain, and sun. It can also be easily placed in an agricultural field, where Barn Owls are more likely to be drawn to the large, conspicuous nest hole.

The boxes are not inexpensive. They run about $169, plus the cost for the pole and other elements. New Hope Audubon uses a sturdy, wide diameter pole system that brings the total cost to about $250 per box. The costs, however, are alleviated by the fact that these boxes do not need to be replaced every few years.

Mark Browning's nest boxes have been used successfully in such diverse settings as the Florida Everglades and California wine country. Mark has shown that use of plastic molded nest boxes dramatically increases Barn Owl populations in California vinyards, where they eat copious amounts of pocket gophers. Because pocket gophers can do inestimable damage to grape vines, vinyard owners are praising the economic value of having Barn Owls on their property. Integrated Pest Management systems such as these have also been successful at reducting rodent populations in Florida sugar cane fields.

For more information on these Barn Owl boxes, and Mark Browning's work, visit www.barnowlbox.com. More information on using Barn Owls for pest management can be found at this link. We hope to have Mark come down and give us a guest lecture on his work in 2014.