Barn owls are an endangered species in the state of Iowa, mainly because of habitat loss, Anna Buckardt, avian ecologist for the Iowa Department of Natural Resources, said.

In an effort to boost populations, the department began a nest box program in 2016 with a goal of establishing 40 active nest sites, distributed among at least 15 counties, within a five-year period.

That would move them up from "endangered" to "threatened."

A similar program with an identical goal was undertaken in 2008 by the Illinois DNR, and it has been successful, Tara Beveroth of the Illinois Natural History Survey, said.

In the more recently undertaken program in Iowa, boxes were placed on state- or county-owned land mainly in the southern half of the state because that area generally has rougher, grassier land and thus is better habitat than the more highly cultivated or developed northern half. The box nearest to the Quad-Cities is in Johnson County, where Iowa City is located, Buckardt said.

Barn owls need at least 200 acres of grassland on which to hunt, and it's better if the land is contiguous rather than on scattered sites. They especially like field edges, fence-rows, and wetland edges where their favored prey, voles and mice, is most available.

They also need nesting sites such as cavities in old silver maples, sycamores and white oak trees and, yes, barns.

Development, changes in cropland, removal of hedgerows and draining of wetlands has destroyed much of the barn owl habitat. And large-scale removal of abandoned farm buildings and adjoining wood lots has diminished nest sites.

Because a barn owls' diet is almost exclusively rodents, rodenticide use on farmsteads can poison them. A final threat is the larger great horned owl, which eats barn owls.

In addition, barn owls don't have a very high over-winter survival rate, typically living only two to four years, Buckardt said. By comparison, the great horned can live 20 years, she said.

• Are you interested in helping? If you are a landowner who is interested in putting up a nest box and would like more information, go to the website iowa dnr.gov/Conservation/Wildlife-Landowner-Assistance/Technical-Assistance/Barn-Owl

You also can help the DNR by reporting barn owl sightings to the Wildlife Diversity Program at 515-432-2823. Please note the day and exact location where the owl was seen.

In Illinois, go to https://www.inhs.illinois.edu/research/moon/