This is a summer resident in cat-tail marshes in southern Ontario. In northern Ontario such marshes are widespread and only a few pioneer colonies have been found there.
Males have a habit of making a number of “dummy” nests, one of which may be lined and used by females to raise the family.
This is a small wren, usually confined to cat-tail marshes, with a dark crown and prominent white line over the eye and white streaks on the back (a feature shared with the Sedge Wren, which differs in having a streaked crown, very inconspicuous eye line and much shorter bill).
The song is a jerky “zhuh-wee-wuh-wuh-wuh-wuh…”
Dr. J. Murray Speirs
excellent description – very helpful