Today, while retrieving groceries from the car, I heard an unfamiliar bird song--melodious, but not a wren. Given the density of foliage on the holly next to the driveway, I didn't see the singer, but on a return trip, I sighted the likely noisemaker, a smallish brownish bird scratching in the mulch under the holly. We generally have a slew of sparrows, but this wasn't one I knew: not a house sparrow (those usually hang out in droves and fight each other for feeder access); not a chipping sparrow (too big); not a white-crowned (no white crown); not a song sparrow (no breast striping).
This visitor's identifying feature was a white breast with a single dark spot, much smaller than the spot on a male house sparrow, so I knew that this was a new bird for me. I didn't get as good a look as I would have liked (and of course the bird was long gone by the time I could get the camera from the house), but a perusal of the Peterson Field Guide suggested that our ground-feeding avian was an American tree sparrow, an identification confirmed by a recording of its song on the Cornell Laboratory of Ornithology website. Spizella arborea is a new bird for me. If I kept a life list, I could have added to it today.
The Peterson lists the tree sparrow as "fairly common," while the IUCN lists it as a "species of least concern." Somehow, I had managed not to notice the common bird for more than fifty years.
I need to get out more.