Northern Cardinal (Cardinalis cardinalis)
I just assumed that this was part of their mating ritual, as I've only seen them do this in the early spring.
Love the pic! It is part of their courtship behavior, even though they're lifelong mates. It's sort of a "tender moment" between the male and female. He'll also feed her during incubation. I've seen it tons of times, but have never been able to get a photo of it. Thanks so much for sharing!