Here's two fast relief pills to take online for learning bird vocalizations and, in particular, wood-warbler songs:
1. Go to xeno-canto.org
Type in the name of the nemesis bird that has you flummoxed (It's free, but you need to create an account with your use name and password).
2. To assess warbler species' songs and calls, go to the following web site that's associated with the excellent, incisive book The Warbler Guide (by Scott Whittle and Tom Stephenson):
You may also wish to view:
and click on the "Companion Guide" button on the right side......Comprehensive information (!)
Otherwise, feel free to see my web site's home page and the "Birding Links" tab pulldown menu where a free handout titled "Top 10 Tips To Improving Your Birding By Ear" appears.
Happy birding and warbler hunting to all, Daniel