House and Carolina Wrens are fairly common but you rarely see more than a pair at any particular location. We've had House Wrens nest in a box in our back yard, and we've seen Carolina Wrens in our yard and around the area. In my experience, it's a toss-up as to which is the most common in New Jersey. Of the less common wrens, one Winter Wren showed up in the front yard back in 2013 and I've encountered Marsh Wrens only at Forsythe.