I've been watching the falcons for two years and have only ever seen them deliver/eat various birds. This morning, however, at roughly 9:00AST it seemed Trey delivered a rodent to the nest. Do peregrines occasionally substitute rodents when a bird might not be readily available?
As an aside, there seemed to be a funny exchange between Princess and Trey. She seemed to look at him with some puzzlement when he arrived, he fretted about for a moment, and then Princess appeared to shoo him away before tearing into the little critter.