Thanks to all of you who participated in the inaugural Plume Zoom quiz! I deem you all Darn Cool Birders just for making the effort.
Everyone got the Song Sparrow ID correct, which is awesome. The American Tree Sparrow was a little more tricky. It took me a few seasons before I was able to differentiate it from the Chipping Sparrow that one of you guessed. One way to tell the Tree Sparrow apart from the Chipping Sparrow is that the Tree Sparrow has a bi-colored bill (the top half is grey, the bottom half is yellow). Another characteristic that sets the Tree Sparrow apart from the Chipping Sparrow is breast markings: Tree Sparrow has a spot on its breast (not visible in this photo), whereas the Chipping Sparrow is clear-breasted.
Don't let my information about sparrow markings trick you into thinking that sparrow identification is easy for me. Quite the contrary. Every FeederWatch season is a lesson anew in sparrow ID. Sometimes there are as many as 4 different sparrows on the ground at once, and I'm often looking at them from up above, so seeing breast markings is sometimes a challenge, and keeping them all straight enough to count each species is even more of a challenge. Who has 1 wing bar and who has 2? Who has a spotted AND streaked breast? Who has just the spotted breast? Eye stripes? Eye rings? Pink bill? Yellow bill? AAARGHHH!
The challenge, however, is part of why I enjoy FeederWatching. It helps me to feel more engaged with the birds, and to appreciate them in their uniqueness.
By the way, there's a great guide to tricky sparrows over at the Great Backyard Bird Count site, along with other tricky bird ID guides, and great birding info in general.