What a difference a day makes for a sparrow

Yesterday, I mentioned that the local song sparrows were singing full volume. It was bright and sunny and felt more like an August day than late September. Today, warm but overcast with a cool front moving in. Today's sparrows were whisper singing. I did some playback (I wonder what my neighbors think) and I kicked up one sparrow that was curious (rose out of the shrubs) but did not act aggressively (didn't move towards me). Is testosterone that responsive to environmental conditions?