Readers Digest Book of North American Birds; ISBN 0895773511; 1990. A Fufous-sided Towhee: Pipilo erythrophthalmus: "Scratching about with one foot at a time, like barnyard poultry, rufous-sided towhees gather their food from the very bosom of the earth. It is little wonder, then, that these active birds used to be called ground robins, especially since their well-hidden nests of stems and leaves are nestled so close to the ground. Today they are named towhees because that is the sound most people hear in their song. But they were once known as chewinks, from the call they make when alarmed. In some parts of the West that call is phonetically transcribed as shrenk, while in others it sounds more like the meowing of catbirds. In sections of the Southeast they unquestionably call Louise! And although their song is translated into English in most parts of the country as "chip towhee" or "drink your tea," the birds seem to drawl it in the South, and are apt to sing chip chup chup zeeeeeee, or just a buzzy zeeeeee, in the West. Their visual field marks too are almost as varied as their vocal ones. Rusous-sided towhees in Florida have white eyes instead of red ones, and those in the West have two white wing bars plus numerous white spots on their wings and backs. But no matter where they live, all rufous-sided towhees come flying in low to the ground with the side patches in their tails looking like white chiffon streamers trailing dramatically behind them."

Try looking up the sound of a titmouse and a Carolina wren. They have various songs, and be sure to listen to them all. (All about birds has good audio stuff). I don't think you'd find either of those birds at your feeder, but they might be close by.

Have you actually seen the figure of some kind of bird in your tree? If not, I'd go with the frog/toad idea too. We have lots of them around here and they typically start up when it's about to get dark. Ours give just one "quaaaaack" at a time.

Wow! What a great find! Such a sweet little bird. Good job on that ID...Warblers can be tricky. We have many birds that stop by our feeders during migration, both spring & fall. It's a fun time of year for birders. The link you posted was from Cornell. Do you participate in their Project Feeder Watch? I signed up three years ago and have learned a great deal. It has really helped me to focus on what birds are in my yard. I enjoy finding new birds and can work for hours and days on making sure of my final ID. It's fun to look at the data from around my own area as well as state and nation wide. I've enjoyed it. sooey