Cliff Swallow.
A fledgling.
Adult feeding fledgling. At some point, many in the colony leave the nesting site and hold a Jamboree. Hundreds of birds can be present and they seem to be schooling the young. I’ve seen Red-Winged Blackbirds and Grackles do this as well, in one case all mixed together. This shot was taken July 12.
The Cliff Swallow mud nest has a single entrance. The Barn Swallow nest is a shallow mud bowel. 
Under any bridge can be found Cliff Swallow nesting colonies. A few Barn Swallows may be there as well. (For some reason I have neglected to get a Barn Swallow picture.)