My brain said I blew the ID and it certainly must have been a first spring Chipping Sparrow that had not molted yet, right? Never mind that all Chipping Sparrows looks the same in the spring after molting on the wintering grounds. And, this bird looked nothing like a Chipping Sparrow. It had a pink bill, white eye ring, pinkish-brown crown, auriculars, and upper breast, and gray underparts. It looked more stout that a Chipping Sparrow and lacked the slim forked-tail of that species.
Fortunately, I had a video camera in my car to capture the bird singing. Unfortunately, the bird was uncooperative and spent most of the next 20 minutes at tree-top level singing. Since I had my obstinate puggle (pug-beagle mix) in tow, I decided to give up, since Buster's leash was getting tangled in plants and shrubs as I tried to watch and film the bird. We were in the car leaving when I spotted Deb Cooney, a fellow birder. I stopped and told Deb about the bird and asked her to confirm the ID for me. So within minutes of deciding to leave, I was listening to the bird again with Deb. The bird finally came to the ground and we had excellent, but brief, view of the bird in the open. There was no doubt the bird was a Field Sparrow. Nothing at all suggested Chipping Sparrow. Deb confirmed the Field Sparrow ID.
You can hear the bird singing in the video but you can't make an identification by sight. I am confident the bird identified as a Field Sparrow was singing a Chipping Sparrow song. Also, the chip notes of the bird sound more like Chipping Sparrow than Field Sparrow.
A few screen captures provide hints of a Field Sparrow identification. The still captures show buffy/gray underpartsalong with a fairly pale face. The bird lacks the rufous crown and the black and white facial markings of a Chipping Sparrow. Oh, I wish I had better video equipment.
Why is a Field Sparrow singing a Chipping Sparrow song? The likelihood that the bird is a hybrid would seem low since no Chipping Sparrow characteristics were observed. Did this Field Sparrow learn a Chipping Sparrow song? Well, ornithologists tell us oscines (most songbirds) learn their songs while suboscines (flycatchers in the US and other species in Central and South America) have songs that are innate. Somehow, this Field Sparrow learned the song (and, I believe, chip notes) of a Chipping Sparrow rather than its own species. There is at least one other instance where a Field Sparrow was observed singing a Chipping Sparrow song. It is when L.L. Short had such an encounter on 30 June 1965 in Yanktown, South Dakota. Both Chipping and Field Sparrows nest in the same patch of open woods (Walnut Plantation) at Fort Harrison. I will keep my eye on this bird to see if it pairs up with a female. And, if so, a female of which species?
Have fun on the birding trail!