This morning while birding at North Shields Ponds, I found this small Spizella sized (think Brewer's or Clay-colored) sparrow. It was pretty twitchy and jumpy, but I was able to get a few photos of it from about 100m away. Bright eye ring, single white wing bar, rufous crown, etc. felt right to me for Field Sparrow. I'm attaching a couple cropped photos of it here. Bird was along the Poudre River just south of the larger reservoir (
https://goo.gl/maps/cvNc4odm4XXSiCYT8), but moved toward the northwest along the willows and cottonwoods that line the trail here.
Otherwise, there were several Orange-crowned Warblers, Yellow-rumps were everywhere, and a Savannah Sparrow sand for me from a large willow.