Tree Swallows, and other swallows

Many many swallows are out and about on the creek. 30-50 would be my guess. Most of them have blue backs, and white bellies and chins, thus I believe them to be tree swallows, but I did spy one that was brown, but don't have many descriptive photos of it I don't know what kind that one is. Remember you can click on my photos to enlarge them.