But in the spring there is a window, right now, when we central Texans sometimes get to hear winter birds like Spotted Towhees singing. The birds start to exhibit some breeding-related behaviors (like singing) before they leave for their northern breeding grounds.
Here's the Spotted Towhee I got to hear singing:
You can listen to it's song isolated from others here:
And here's the recording I made with my iPhone of the bird this morning. (It's mixed with several other bird songs and calls.)