New Barn Owl Box Installed in Northern Virginia

Photo: Barn Owl, Michael Phillips/Audubon Photography Awards

Tina Dudley

Barn Owl, Michael Phillips/Audubon Photography Awards

The ASNV Conservation Committee is excited to announce the successful installation of a new barn owl nesting box in an unused silo in a park near Leesburg. This project was implemented by our friend and raptor advisor, Liz Dennison, in partnership with NOVA Parks.

Liz Dennison, president of Secret Garden Birds & Bees, a nonprofit, also worked with the Conservation Committee to help us install two Kestrel nesting boxes at the Lorton Landfill in 2022.

The effort to find a suitable location to install the barn owl box began at the end of last year. We investigated a few siloes close to the Lorton Landfill, but each silo proved to be problematic for different reasons. Several were completely inaccessible, welded shut in fact. Another was accessible but, due to poor drainage, had several inches of water in the bottom. This was a problem because when young barn owls fledge, they often fall from their nest as part of the process of learning to fly. We did not want to risk the fledglings drowning accidentally.

We found the perfect silo by posting a question to Reddit’s NOVA community - asking if anyone happened to know about a silo that might be suitable. One commenter replied that it was a strangely specific question to post. Luckily, one reader in the thread happened to be an employee of NOVA Parks, who contacted us with a lead on a good location.

This park, which we are not identifying to prevent harassment to any future nesting owls, is the perfect site. It has ample grassland nearby to provide a bounty of mice and voles. Barn owls have in fact been spotted in and near that park by NOVA Parks staff. The silo also is in a part of the park that is closed to the public.

Although Barn Owls prefer to nest in barns, they will use a silo because the silo helps protect the owls from the elements. Liz shared a memory of the first time she and Dave installed a barn owl box in a silo on her own property. “I did not have high expectations because I did not think we were in good barn owl territory. But I was wrong. Just a few weeks after installing the box, I stuck my cell phone through one of the silo doors and snapped a picture of the box. And there was a beautiful barn owl face looking down at me! The owls are still here and still using the box to raise their young.”

Nest box in the silo, Liz Dennison

It was Liz’s brave friend Dave Cazenas who actually climbed high up into the silo to install the box. He also brought his drone and was able to capture this great image of the silo and the surrounding habitat.

The chosen silo, Dave Cazenas

Liz explains why this location is ideal: “This silo in the park is perfect. The silo, despite missing a roof, is in good structural condition, which made installation safe. The surrounding area is perfect for hunting mice and voles. It’s quiet and away from people. And young barn owls will have plenty of sheltered places to roost as they master their flying and hunting skills. Without disturbing them, we will check for signs of the owls – owl pellets (bits of indigestible bone and fur regurgitated by the owls) and molted feathers.”

She also asks for public cooperation: “If anyone recognizes this place from the photos, please keep your distance from the silo and other structures. We want the owls to feel safe exploring the site and choosing it for their nest. It could take some time – or it could take just a few weeks. But I’m confident that a pair of barn owls will eventually make it their home.”

Many thanks to Liz and Dave, and to Emily Johnson from NOVA Parks, who suggested this location and coordinated with our volunteers who installed the nest box.

We hope to have good news of a nesting pair to report back soon!

If you know of a silo that might be suitable for another nesting box, you can contact us at info@audubonva.org with your suggestion.

We would not be able to do projects like this without the help of our donors. Thank you for your support. To contribute, you can make a donation online at https://www.audubonva.org/donate.

Yellow Eyes in Moonless Skies: Researching the population status of the enigmatic Northern Saw-whet Owl

Photo: Northern Saw-whet Owl, Gary Zeng/Audubon Photography Awards

Deidra Bryant

There’s something truly delightful about autumn nights. The crispness of the air, the sound of the trees rustling in the wind, and catching a glimpse of fluttering owls from deep within the woods. Northern Saw-whet Owl migration kicks off in late October which means another season of observing these elusive raptors!

The Northern Saw-whet Owl (Aegolius acadicus) is tiny, with adults averaging 8 inches long and weighing 2.8 ounces. That’s lighter than most smartphones! They can be found in the coniferous and sometimes mixed or deciduous forests of North America. However, they are very difficult to find due to their diminutive size and ability to camouflage into their environment. During my first year of graduate school I had the opportunity to observe these tiny hunters on clear nights atop South Mountain at Kings Gap Education Center in Carlisle, Pennsylvania.

Each autumn, these owls migrate southward from Canada, while licensed banders and dedicated volunteers capture, band, and safely release them back into the wild. This large-scale project in PA dates back to 1997 and is coordinated by natural historian Scott Weidensaul. Project Owlnet tries to learn when saw-whet owls migrate, map their movements, and contribute to an informal data network consisting of information from at least 120 stations across the continent.

Saw-whet owls are lured into mist nets with recordings of the males’ breeding call while scientists await their arrival nearby, taking turns checking the nets every 40 minutes. Once caught, a volunteer or two will carefully remove the owl from the net and put it into a cotton drawstring bag to calm and protect it en route to a room with a licensed bander. Upon arrival, birds are weighed and everything is measured to age and sex them. This includes their wingspan (females tend to weigh more and have a longer wingspan than males), the size of their beaks, and the amount of fat they have on their bodies.

A black light is another valuable tool which is used to observe color patterns in the feathers and estimate the age of each individual. On most owls, the undersides of the remiges (flight feathers) will glow a brilliant neon magenta in the presence of ultraviolet light. This is due to porphyrins – a type of pigment that many orders of bird species use to pigment their egg shells as well as their plumage. Sunlight exposure causes porphyrins to break down. As a result, older feathers will fluoresce less brightly, showing new growth.

After measurements are documented, the birds are then banded with unique numbers on their legs and released back into the wild. Each owl differs in temperament, which adds to the whole experience. Some will puff out their feathers and clack their beaks in a menacing manner, while others will show a curiosity towards the scientists. I highly recommend anyone who’s interested in bird banding to volunteer!