Watched an American Tree Sparrow (ATSP) singing this morning while walking on a path through the Bell Trace senior living community on east 10th Street in Bloomington.
I'm familiar with ATSP foraging calls when they are in winter flocks. When you get a flock of 100+ birds doing these calls all at once, it sounds like a breeze blowing through delicate glass wind chimes.
I don't think I've ever heard an ATSP in song before. They breed in Alaska and northern Canada, so I imagine they do most of their singing WAY up north. I wouldn't have been able to pin down what it was if I hadn't seen it singing. It was perched in a small tree, maybe ten feet up.
I'm not claiming it's unusual to hear an ATSP sing in southern Indiana. I don't know if it is, or if it is not. But personally it was a cool experience!