Thanks to lots of comments from birders across the land, I can now say that the bird pictured is an immature Clay-colored Sparrow, Spizella pallida. To be honest, we had originally landed on Grasshopper Sparrow when running it through the Robert's key but many of the characteristics are iffy at best (e.g. broad and pointed tail feathers vs. narrow and pointed tail feathers. How broad is broad?) I also have to say that Mark had suggested Clay-colored originally until we started questioning that ID.
Other suggestions from comments included Lincoln's, and Vesper. Special thanks go to Bruce Fall and Allen Chartier for their insights. Birders are such a great group of people. So, one more learning experience in the archives. Next banding session will probably teach us something else, and isn't that the way it should be?
I'm working on tomorrow's post which will be about putting radio transmitters on Purple Martins last Sunday. It was pretty cool!