As requested, here is the bird's back:

I also have many photos nearly identical to Serge's, so I'll post ones that give a different view:


These thrushes gave us a merry chase, spending most of their time underneath the ferns, then coming out to chase each other around our heads, lighting for nearly exactly four tenths of a second less than it took to focus.... but it was fun. We also saw Black-capped Chickadees, a Brown Creeoer, and this, which I took to be a juvenile Sapsucker:

The bird Serge referred to at first was a beautiful, unmistakable male Indigo Bunting that caught the sunlight as he flew in front of the van, and promptly disappeared into the cornfield, leaving me delighted and Serge strangely unfulfilled...