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Endangered barn owls thriving in one Iowa woodlot

Join Iowa DNR Biologist Bruce Ehresman as he describes a night among barn owls, great horned owls and raccoons – all in one special north Iowa woodlot.

By Bruce Ehresman, Iowa DNR Wildlife Diversity Bird Biologist
Photo by Tom Litchfield, DNR Biologist

Barn owls, an endangered species in Iowa, have a nighttime snack in this special north Iowa woodlot | Iowa DNRWhen my wife Marlene and I arrived at this north Iowa acreage and stepped out of the car (about 8:15 p.m.), we immediately heard the squawk of a black-crowned night-heron and a rasping screech – the food-begging call of a barn owl. This heron is a rare nester in Iowa these days, and the landowner – not aware of its rarity – matter-of-factly mentioned, “yes, they nest here.”

The landowner, Bob Muller, lives on this northern Franklin County acreage near Sheffield with 8 acres of old trees, mostly silver maple and box elder. Then there’s the house and a couple of old farm buildings, all completely surrounded by cornfields. Several years ago Bob reported to Mark Leoschke, DNR Botanist, that he had barn owls nesting on his property. At that time, Bob thought that barn owls were very common since they had been nesting on his property, several times, since 2006. But they’re actually an endangered species in Iowa.

A few years ago, when I talked to Bob on the phone, I became immediately intrigued with the uniqueness of this barn owl nesting site, especially because it’s several counties north of where this species is usually found. I then spent a few hours one evening walking around Bob’s woodlot, studying what factors are in place to attract the barn owls to keep returning to that site. While there is a significant amount of bur oak savanna (ideal Barn Owl habitat) two miles to the south of Bob’s acreage, the primary nearby foraging habitat that might contain voles, barn owls' favorite prey, seems to be grass waterways.

When I visited Bob the first time, I was amazed at his intelligence and knowledge (he knows the scientific name and medicinal properties of nearly every plant on his place), he knows much about every wild animal species that exist there, and he seems to have a near photographic memory of whatever he sees, based on his extremely detailed descriptions that he continually provided us. When Bob was younger, he helped his dad on the farm. Now he refers to himself as a horticulturist. He tends the woodland and adds native plants to it. His reverence toward the land and nature is contagious.

Now, back in the woodlot again, Bob took us to the area with hollow silver maple trees where he was pretty certain the barn owls had nested. We could hear four, eventually five, barn owl youngsters food-begging. I also made out the tinkling call (usually associated with pair-bonding) of what I believe was the adult male – it could be that the female was already sitting on a second clutch of eggs in a nearby tree cavity.

While we were standing there listening, I heard the purring sounds of baby raccoons and then witnessed a mama raccoon and her cubs coming out of a tree cavity. This was very close to where Bob thought that the barn owls had nested. Because raccoons are known to eat barn owls, this co-existence seems an extreme anomaly!

As it grew darker, we moved back toward Bob’s house and near a few isolated large trees, into which Bob assured us that the barn owls would fly. The owl young indeed did move toward these trees, screeching as they went.

Many years ago, when Marlene and our boys and I lived on an acreage north of Boone, we had barn owls nesting in our barn. When the young fledged, they would routinely start food-begging toward dusk. Then, when the male flew out of the barn and headed out to hunt, we would witness the youngsters flying after him, screaming as they flew. Now, 25 years later, we were provided another opportunity to again witness this wonderful event - at Bob’s home. We watched a barn owl fly south over the cornfield with one of the youngsters in close pursuit, screaming as it flew. That sight made my heart happy!

While we were standing in the yard listening and watching, completely surrounded by the five food-begging barn owl young moving among the trees, Bob mentioned that a few nights ago he had witnessed two fledgling great horned owl youngsters, perched on the shed – next to which we were now standing. Shortly thereafter, we heard a harsh and somewhat agitated call, coming from the woods, 40 or 50 yards to the north of us. Marlene asked, “what is that sound?” I answered, “I think it is coming from a great horned owl.” Marlene played her Audubon bird app, and the call indeed was an agitated alarm call from an adult great horned owl. So – again, we documented another well know barn owl predator, the great horned owl, raising a family of young in the same woodlot where barn owls were apparently fledging successfully.

From everything I had learned through our research and the research of others, this is not supposed to happen! Yet it is happening, apparently year-after-year, at this very special place with this very special man, who, with genuine love in his heart, reverently tends this woodlot and all its inhabitants. As a scientist, I can interpret the fact that barn owls are nesting successfully amongst their two main predators, great horned owl and raccoon, as an exception to the rule. As a fellow human being, I interpret what is happening at Bob’s woodlot as a bit of Nature’s magic, or more preferably a very good example of the effects of love of wildness and repeated acts of kindness toward the earth and all of our fellow inhabitants.

 

 

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