Our yard is host to a kind of bird I haven't seen before this year and one that's been frustratingly difficult to identify. Needless to say, I haven't got any photos -- I only wish I had. I hope it's something common enough to the area that a more experienced birder will be able to guess it easily.

It's a small bird, about twice the size of a bushtit (or comparable to a sparrow) and the pair of them hang out near an unidentified pine tree where chickadees nest every year. In the evening they sing back and forth long, elaborate songlike calls which I thought at first were a robin, but they're longer and more musical.

The only visual impression I've been able to get is a light color, maybe gray but more likely tan or buff. I don't see any barring or other pattern on them. They fly with a dipping pattern like sparrows do. They aren't house sparrows, chickadees, robins, waxwings or goldfinches. Maybe some kind of vireo? We live in N. Tacoma, so fairly urban backyard habitat.