"Cheery-Peep"

This morning before work while taking Buster for his bird walk on the Lagoon Trail we heard a distinct bird song we did not recognize. After some time we located the singing bird high on a tree top.  Jeanette wrote down what it sounded like as - - "Cheery-Peep".  We spent the next 20 minutes trying to match the song with a bird.  I took 23 photos in trying to get a definitive view. It was behaving like a flycatcher, but it's song was like no flycatcher we could find on our iPhones. We were stumped until later in the morning at a different location I heard and saw an Olive-sided Flycatcher make a similar strange song following it's traditional song which is usually described as "Hick-Three-Beers". If any of you out there in bird-land have a better understanding, please let me know.  Other wise I have now learned that an Olive-sided Flycatcher has more than the one "Hick-Thee-Beers" song.