This youngster was sitting with 3 Barn Swallow juveniles alongside the parking lot at High Pines. I noted the color on the throat which I've never seen before - nor is it referenced in the field guides - and thought maybe there had been some gene-mingling going on with a Bank and Barn Swallow! When I checked the Cornell Birds of North America Online I found that in juvenile Bank Swallows the "chin, throat, and side of neck often are slightly washed with pink or buff and sometimes with faint, grayish brown spotting. Some individual variation in extent and color of pale fringes and rufous wash". This coloration appears to be what that comment refers to!
I note in this photo that the "wash" appears to faintly tint the forehead as well - though Cornell doesn't mention that.