Now I am more inclined to think its an immature (less than a summer old) night heron of some sort, most likely a Black-crowned Night-Heron. The "immature" part of the ID would explain the relatively dull coloring, and the fact that I was able to get as close as I did to get these shots.
(Note: the pictures look somewhat more impressive if you open them in Paint. You can see a fair bit of detail at that point).
And here's my attempt at an "artsy fartsy" shot of the scenery around Walden Pond, where the above pictures were also taken.Okay, so maybe "artsy-fartsy" isn't my thing.