The US Fish and Wildlife Service has identified the Burrowing Owl as a candidate species and in several states they are considered a species of concern. They are endangered in Canada.
I think the 2 most interesting Burrowing Owl factoids are that they live in underground burrows (hence the namesake) and to ward off danger the chicks make a sound identical to that of a rattlesnake. There is a fantastic video of Bob Fox, co-founder of Wild At Heart, on the AZ Game and Fish Dept.'s website that demonstrates the chicks convincing performance.
Wild At Heart is a non-profit dedicated to the conservation and preservation of Arizona's native birds of prey. Through The Burrowing Owl Project, this organization is helping relocate owls that are in danger of losing their natural habitat due to suburban development.