Which wren?

I took these photos this morning, in central Kansas in a hedgerow bordering fields/pasture. A major wetlands is a mile or so east of here. I originally assumed 2 different species, since I took the photos in different places along the road, but still within a couple hundred yards of each other. Comparing the birds when I got home, I can see where they might be the same species, but I don't know.

Here is the second bird. It was definitely small enough to be a wren, and that was my fleeting impression when I saw it. Thanks for looking.

I'd say Marsh Wren for the bottom image Rob.I'd guess on the first image that it is an immature Marsh Wren, but I might be wrong on it.

Thanks Mia and Cindy. I haven't seen many Marsh Wrens, hopefully this bodes well for the winter :).