I don't know much about birds, but one camped outside my bedroom window about a week ago, and every day since it has sung its early morning song.
It surprised me today. Last night the ice lacquered my car before the changeover to snow, and I couldn't chip the windshield free without the heater softening the ice up, and I couldn't get to the heater without pulling down on the door handle with my body weight until the door cracked open. This morning, jets fly by and snow plows rattle with the muffled acoustics of a respectable snowfall. This seems no place for a bird, yet there it chirped.
Sometimes the specific form it will take is less important than knowing that spring still is scheduled.