Not sure if that was a Great Horned Owl you heard last night? Here is an easy way to find out. The Cornell Macauley Library of sounds and videos of birds and other animals is now online and free. http://www.animalbehaviorarchive.org.
The site is not limited to birds. You can listen to about anything you want.
The Cornell Lab of Ornithology operates the incomparable Birds of North America website (http://bna.birds.cornell.edu/bna). It has a comprehensive reference covering the life histories of North America’s breeding birds.