Birds That Whistle in the Night

Have you ever heard birds whistling in the night?  Often, when Marash Girl is in the kitchen preparing dinner, after dark, (and specifically last night,) she hears a bird whistling.  [Marash Boy heard it last night, although he had never heard it before, as he is rarely in the kitchen while Marash Girl is preparing dinner.]  The whistle is almost as clear as that of a cardinal, but not the same in tune or lilt.  Searching the internet for an answer to this puzzle, Marash Girl found nothing.  There were a few queries by others who had heard similar whistles, and the only answers?  Tree frogs.  Marash Girl knows tree frogs and hears those as well, but this whistle is that of a bird.  She listened to every bird call that was offered on the internet, and none matched the whistling that she hears. Has you heard a bird that whistles in the night?

It is now 9:28 AM and I hear the same bird whistling in the light, not as insistently, but still whistling.  What bird is it?