Black Phoebe singing it's heart out

I heard this apparent Black Phoebe (didn't see it close enough to rule out hybrid traits but looked and sounded like a Black Phoebe) singing it's primary song vigorously along the Canon City-CO Riverwalk this morning. I heard then saw an apparent Black Phoebe yesterday about a quarter mile further east adjacent to the Riverwalk so it may have been the same bird as I didn't have time to check the earlier location. It continued singing for several minutes as it flew up unusually high (about 40 or so feet up in a large cottonwood tree) where I got this photo. It is most unusual for this species to perch at canopy level of large trees and though I observe phoebes frequently I rarely get a view from directly below the bird like this. After it flew further off it continued singing it's primary song for a total of more than 5 minutes consecutively, not unusual for Black Phoebes though it did continue rather a long time for winter singing. SeEtta