question about songbirds after dark (1 Viewer)

I live in portland oregon and this is my first post here... hello to all.
I hear a bird in the early morning hours spring through fall. They tend to be solitary and have a song that comes in a pattern of threes. They seem to sing only at night, just after sunset and again just before sunrise, however last night they started up at about 3 am. Can anyone tell me what breed of bird it is that I hear at night and why it is that they prefer the dark. When I think of nocturnal birds, I tend to think of owls alone. It has a beautiful call.

My hunch is that this songster is the common and unappreciated robin. Where I live, the notes are usually in groups of five, not three, but I'm sure it varies, it doesn't sound like a fixed phrase. The robins are the last ones to stop singing at night and the first ones to sing in the morning, where I live, and they seem to like to do their main loud singing when the other birds are quiet, which fits the behavior you describe (ie., you only hear them doing that song in the late dusk and early dawn). And it also fits that they are solitary when they sing (though if you live where there are a lot of robin territories you can hear various ones singing from different spots). Robins actually are great singers and can be amazing singers during courting season. But they are so common, who gives them a second glance?

(Robins don't sing during the dark of night, though, only late dusk and early dawn, and I have never heard them as early as 3 am, so if your bird is really singing at night, he may be some other bird, no idea what. Mockingbirds are famous for night singing, but we don't have them here.)