We have been getting a lot of owls around here in recent months. The two most common kinds are the Great Horned Owl and the Barred Owl. The Great Horned Owl is a very large owl that makes the sound that most people associate with owls: hoo, hoo, hoo-hoo. The Barred Owl is almost as large and makes a highly unusual sound that can almost sound like a barking dog. It roughly sounds like hoo, hoo, hoo-aw! I tend to hear these owls either right around dusk, or late at night. The most unusual owl I have heard is the Saw-whet owl. It is a very small owl, smaller than a robin, and makes a high pitched tooting noise that sounds like: toot, toot, toot. It really doesn’t sound like an owl at all. All of these owls are hard to spot because their coloring (grayish-brown) blends in so well.
Reference: John Bull and John Farrand, Jr., National Audubon Society Guide to North American Birds, Eastern Region, revised edition (New York: Chanticleer Press, 1994)