For recordings of bird songs, call 612-673-7800, and when prompted press the following four-digit numbers:
1228 black-capped chickadee
1229 great-horned owl
1230 red-breasted nuthatch
1231 Northern saw-whet owl
1232 white-breasted nuthatch
Recordings from the Library of Natural Sounds, Cornell Laboratory of Ornithology. Try the lab's website: www.birds.cornell.edu.