Thanks for the responses. I have been listening to Wood Thrush recordings online and didn't find any with the repeated two notes followed by trill. But I think the wood thrush identification must be right. I guess individual wood thrush can have quite different songs?
We moved into a new home in Connecticut last fall that has a stream and woods behind. This summer I have regularly heard a new bird I don't recognize. I haven't been able to see it. The song is flute like with trills, somewhat similar to some thrushes, but it doesn't seem to be any thrush I can find recordings of. Attached is an audio recording. Let me know if any of you recognize it. Thanks, Greg Unknown Bird Song.wav