Certhia americana (brown creeper)
Here's the song, sung in the Ponderosa Pines near the top of Oak Creek Canyon of Central Arizona, 4/10/99. The song is so high (between 4500 and 8000Hz) that many humans just can't hear it at all!
Douglas Von Gausig (recordist; copyright holder), Naturesongs.com

This work is licensed under a Creative Commons Attribution-Noncommercial-Share Alike 3.0 Unported License.
To cite this page: Myers, P., R. Espinosa, C. S. Parr, T. Jones, G. S. Hammond, and T. A. Dewey. 2013. The Animal Diversity Web (online). Accessed at http://animaldiversity.org.
Disclaimer: The Animal Diversity Web is an educational resource written largely by and for college students. ADW doesn't cover all species in the world, nor does it include all the latest scientific information about organisms we describe. Though we edit our accounts for accuracy, we cannot guarantee all information in those accounts. While ADW staff and contributors provide references to books and websites that we believe are reputable, we cannot necessarily endorse the contents of references beyond our control.
This material is based upon work supported by the National Science Foundation under Grants DUE-0633095 and DRL-0628151.
The ADW Team gratefully acknowledges their support.