The justification for spending your Saturday building a backyard owl house may be obvious. It’s an environmentally virtuous thing to do. The owls’ haunting trill livens up the neighborhood nightlife.

And baby screech owls may have the highest cuteness quotient of any living thing.

But if you need a less cuddly reason, Fred Gehlbach can supply it.

With a little help from humans, the Eastern screech owl adapts well to suburban environments.

“They eat rats and mice,” the Baylor University ornithologist said. “They’re really good at killing a big old brown rat. Owls get them by stealth, grab them and break their neck. They’ll tear it up on the ground and fly to the nest with the pieces.”

Gehlbach, whom Audubon Magazine once called the “world’s leading authority on Eastern screech owl behavior,” knows owl boxes.

He has placed 20 of them around his Woodway neighborhood and has studied how the construction and placement of owl boxes contributes to their nesting success.

The Eastern screech owl, native through much of the United States and Canada, typically nests in a cavity of a tree starting in March. It’s about 10 inches tall and makes a low whistle, rather than the loud hoot made by the much larger great horned owl.

The female incubates the eggs inside and the male roosts nearby and hunts for food. Their food consists of rodents, insects and sometimes other birds such as blue jays and cedar waxwings. But they tend to leave smaller songbirds alone.

With a little help from humans, they adapt well to suburban environments, Gehlbach has found.

You can get the long version on ideal habitat in Gehlbach’s book, “The Eastern Screech Owl, Life History, Ecology and Behavior in the Suburbs and Countryside.” But here are the highlights:

* Make sure your neighborhood can support an owl colony. A suburban neighborhood with lots of tree cover and perhaps a wooded creek should work fine. Woodway and the Cameron Park area offer good habitat, but older, more urbanized neighborhoods with mature trees may support screech owls.

* Hang up your box by February to prepare for nesting season, which begins in mid-March. The nesting period lasts two months. If squirrels get into the box before mid-March, prop the lid open for a day or two and they’ll scram.

Owl houses can both raise your yard's cuteness quotient and help keep it free of pests.
Rod Aydelotte/Tribune-Herald

* Make the interior floor at least 7 inches on each side. A smaller floor crowds the nestlings and causes them to fledge prematurely, Gehlbach has found.

* Don’t use treated lumber, and leave the inside floor and walls unpainted. Baby owls will peck at the sides and you don’t want to poison them.

* Fasten to a sturdy tree, in deep shade no lower than 10 feet off the ground. The box may face any direction but north. Make sure there’s an open space in front of the box so the birds can fly out.

* If you buy an owl box, avoid those with front or side openings, which could cause the chicks to fall out when you open it.

* After the owls are well into nesting season you can look inside and even pick up the owlets. But only do this during the day when the owls are away hunting.

Gehlbach takes chicks from his boxes and studies them, even sometimes passes them around to groups of visiting schoolchildren. Contrary to popular belief, owls won’t abandon their chicks if they’ve been handled by humans, he said.

Gehlbach sometimes even picks up nesting adult owls.

“Most of them trust me,” he said. “I can put my hand in the box, tip it upside down and put it back inside.”

Which brings Gehlbach to his last piece of advice for would-be owl landlords — Tread lightly.

Don’t look them directly in the eye and don’t make sudden moves. In time, he says, your owls will begin to recognize you as a friend.

jbsmith@wacotrib.com

757-5752

Scott Fagner/Tribune-Herald graphic

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