From the Homeport site above to which Beer referred:"...the Swainson's Warbler is in fact not uncommon in the proper habitat. Typically it is found in bottomland thickets, especially with greenbrier (Smilax) and grape vine undergrowth or canebrakes; a good place to find it is in the Pearl River Wildlife Managment Area along old U.S. 11 in the Honey Island swamp. Its song, with apologies, is a "whee, whee, whee, church is free...", quite similar to that of the Louisiana Waterthrush, which breeds in rather similar habitat, but has a very different ending. The song is loud and sweet and carries well, but it also seems to be ventriloquial. "

No connection to the Northern Cardinal, but another example of carefully observed examples of a similar effect as that about which you are wondering.

I do know how to spell and when to use "whether" as opposed to "weather" or "wether", despite evidence to the contrary at 11:52. :)

m