Chipping Sparrow

Out at the park near my house recently I saw two new birds.  Both had rusty caps, and one had yellow streaks alternating with maybe white or brown? along the head and neck.  Two yellow streaks, I'm pretty sure of it.  And a streaky breast.

The other had a rusty cap and a black eye line and a non-streaky breast.  This turned out to be the chipping sparrow, confirmed by my handy Sibley app on my phone which played its call, matching what I was hearing.

So I went back with camera in hand a few days ago, and managed to take a few pictures.  It's a little blurry, but definitely a chipping sparrow!

I still don't know what the other bird was, and can't find anything like it in my books.  I haven't seen him or her again.

Here's an old friend at the feeder, caught in the sunlight with her eye ring matching the bay: