Sparrows, not Bluebirds

Birdhouse with parent bird in attendance.

The baby birds in the bluebird nest box are sparrows. This was decided yesterday, when a sparrow was seen tending to the nest. Parent birds make themselves scarce once they detect humans about, so the photos were taken from the front porch.

Smaller bird atop fence.

Although I tried to capture the strange interaction I had been observing between the parent bird and the smaller bird on the fence, by the time I got close enough to snap a photo the birds detected my presence and separated. What I saw was the larger bird repeatedly alighting atop the smaller bird, and doing what? I could not say.

Parent bird, perched at a distance, with an eye toward the intruding human.

The interaction was not sexual, I am sure, because it was repeated several times as I approached (trying to remain undetected, and failing miserably). It was almost as if the larger bird was encouraging the smaller bird to move, but when I got close, the smaller bird flew off with ease--so I discarded the notion of flying lessons.

A peek inside reveals little, although I do like the Guinea feather toward the back.

Later I approached the nest box and peeked inside. Rather, I allowed the camera lens to peek inside. Although the parent bird had earlier perched at the entrance, I detected no inhabitants. Perhaps the interaction had been that of a parent coach to a fledgling. The last time I had the leisure to sit still and watch flight lessons, I lived in a Northeastern city; at that time I saw fledglings watched by adult birds, but I do not recall such direct contact.

Anyone with greater insight is invited to share some thoughts. I would appreciate the feedback. Thank you!