Song sparrow singing much less often (but still eats in yard many times/day)

The song sparrow used to sing all day long outside on the young tree.  In recent days, not so much.  Much he and his mate (I assume) still visit many times/day to eat.  Millet is definitely the favourite, which I leave on a plate (and bring in at night), but also they eat from the feeders too.

~1/3 of the time I see the two together, the rest of the time I see just one bird at a time.