[mou] Song ID help

[Pastor Al Schirmacher]

While walking the back side of Blue Hill Trail in Sherburne NWR (near 
Princeton, MN), heard a completely unfamiliar song.  The song was quite loud 
(stop you in the middle of a trail loud, although 25 yards away), medium 
pitch, five notes followed by a bit of a rolling ending. I would describe it 
as wah-weet-weet-wah-whir, with pronounced emphasis on the two weet-weet 
portions (much lower & somewhat slower than a shorebird's weet-weet).

The songs came in two pairs of two verbalizations each, initially sounding 
very near the ground, then at mid-canopy.  The area is oak savanna, 
relatively open woods & grasslands, with the sound initially occuring 3-5 
feet into the woods.  Twenty minutes of pant-staining search through brush 
yielded nothing.

The loudness & pitch was very close to a Carolina Wren, although I'm only 
familiar with its "churry-churry-churry" call.  I could not make a 
determination from Sibley whether it may have been a CW alternate 
verbalization (which is all I have in the car).

Help!

Al Schirmacher
Princeton, MN
Mille Lacs & Sherburne Counties